CHAPTER-5
ELEMENTARY STUDENTS’ CONCEPTIONS
ABOUT ENERGY
5.1
Introduction
5.2
Scientific Evolution of the Concept: Energy
5.3
Pedagogical Perspective of the Concept: Energy
5.4
Development of the Concept maps: Energy
5.4.1 The Intended Concept Map: Indian Source
5.4.2 The Intended Concept Map: International Source
5.4.3 The Derived Concept Map: Energy and Energy Resources
5.5
Students’ Conceptions of Energy: Primary Source
5.5.1 General Analysis of Students’ Conceptions about Energy
5.5.2
Comprehensive Analysis of Students’ Conceptions
Energy
about
5.5.2.1 Students’ Conceptions about Sources of Energy
5.5.2.2 Energy-Meaning, Forms of Energy, Transformation of
Energy
5.5.3 Discussion
5.6
Conclusion
CHAPTER-5
ELEMENTARY STUDENTS’ CONCEPTIONS ABOUT
ENERGY
5.1. Introduction
‘Energy’ concept is a cornerstone in science education which explains many
other phenomena such as work, force, motion, photosynthesis, chemical
reactions, chemical bonding etc (Watts, 1983). Energy concept is considered to
be important because it contributes to fundamental process which allows
predicting and interpreting the behaviours of a wide variety of physical systems
and/or other areas of science. Moreover, the understanding of energy supply
and use within a sustainable development approach (socio-cultural character of
energy) is of equal importance now-a-days. Teachers, leaders, industry and the
public agree that school teaching should equip students with the knowledge,
skills and abilities needed to live in a world faced with rising energy demands
and shrinking energy resources.
The concept of energy is widespread in all sciences and is interpreted in
multitude ways. In the context of chemistry, energy is an attribute of a
substance as a consequence of its atomic, molecular or aggregate structure.
Since a chemical transformation is accompanied by a change in one or more of
these kinds of structure, it is invariably accompanied by an increase or
decrease of energy of the substances involved. Some energy is transferred
between the surroundings and the reactants of the reaction in the form of heat
or light; thus the products of a reaction may have more or less energy than the
reactants.
In biology, energy is an attribute of all biological systems from the biosphere to
the smallest living organism. Within an organism it is responsible for growth and
development of a biological cell or organelle of a biological organism. Energy is
thus often said to be stored by cells in the structures of a biological organism,
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such as molecules of substances such as carbohydrates, lipids, and proteins,
which release energy when reacted with oxygen in respiration.
In school science curriculum, energy is a compulsory topic at secondary level,
but is simplified in primary science curriculum. There seems to be lack of clarity
regarding the developmental appropriateness of the concept, as well as
correctness of possible simplifications (Trumper, 1990). In most cases energy
is associated with sources or from the perspective of objects like battery & fuels
rather than light and heat (Duit, 1984). There appears to be a tendency to
strongly link energy as a property of living organisms commonly associated with
motion or physical work (Solomon, 1992).
The concept of energy is not immutable, as the history of physics show that
ideas about energy are still developing and cropping up in new contexts. Hence
many of the earlier ideas are now considered as fallacies by physicists. Some
physicists have pointed out that we do not know what energy is. If there is no
clear idea of what energy is, teaching the concept must be a problem. There
has been much research on the subject energy: either on students’
misunderstandings (Watts 1983, Duit 1986, Nicholls and Ogborn 1993, and
many others) or on teaching methods in order to avoid misconceptions
(Solomon 1983, Trumper 1990, 1997). Explanations of energy in school
textbooks have been criticised (Sexl 1981, Duit 1981, Duit 1987, Cotignola et
al, 2002 and Doménech et al, 2007).
Duit (1987), for instance, pointed out some inconveniences of the concept of
energy as something quasi material, defended by some physicists. According
to Beynon (1990), there is so much confusion with energy “because it is not
treated as an abstract physical quantity but something real, just like a piece of
cheese”. Empirical educational research shows alternative ideas such as
‘Energy is fuel’ or ‘Energy is stored within objects’ (Nicholls and Ogborn 1993).
There is, however, a reason for that concept of energy. The most common
presentation of energy in contemporary textbooks states: energy cannot be
destroyed nor created but only transformed. If energy can be transformed, then
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forms of energy must exist. Connected with transformation appears the
indestructibility of energy, which reinforces the idea of its reality. Thus, it is
understandable that some textbooks present energy as something quasi
material, as Duit stressed, and students think of it as something real.
The concept of energy took a long time to historically unfold, and is still being
unravelled with advent of modern research at the level of sub-atom or the
universe. The following section traces the evolution of the concept of energy
historically from the time of Aristotle in the 4th century BC to the present.
5.2. Scientific Evolution of the Concept: Energy
The word energy derives from Greek energeia which appears in the work of
Aristotle in 4th Century BCE. The concept of energy emerged out of the idea of
Vis viva (living force), which Leibniz defined as the product of the mass of an
object and its velocity squared and he believed that total Vis viva was
conserved. Gottfried Wilhelm Leibniz 1646-1716) convinced himself that the
true measure of the efficacy of a force is the product of the mass and the
square of the velocity, which he termed the Vis viva or living force, as
contrasted to the “Vis Mortua” or dead force of statics.
To account for slowing due to friction, Leibniz claimed that heat consisted of the
random motion of constituent parts of matter. Isaac Newton too shared this
view, but this was generally accepted more than a century later.
In 1802 during his lectures to the Royal Society, Thomas Young was the first to
use the term ‘energy’ in its modern sense, instead Vis viva. Thomas Young
(1807) defined energy “the product of the mass of a body into the square of its
velocity may be properly termed its energy”.
Gustave – Gaspard Coriolis described kinetic energy in 1829 in its modern
sense and in 1853; William Renkine coined the term “potential energy”.
It was argued for some years whether energy was a substance (the caloric) or
merely the physical quantity.
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The concept of energy and indeed all science is here investigated from the
roots of the concept which is the notion of invariance or constancy in the midst
of change.
A closer approach to the energy construct as we employ it today is found in the
famous treatise by Lagrange, Mecanique Analytique, (1788) he refers to the
conservation of Vis viva. D’ Alembert 1743) can be considered to settle the
momentum vs. Vis viva controversy. The fact remains that D’ Alembert did set
forth the general argument that modern physics has found satisfactory.
Before 1842, Robert Mayer had been to Java as a doctor on board. During an
operation of the lungs he observed that the venous blood appeared lighter in
colour in the hot climate of Java compared to the cold areas of Europe. He
suggested that to attain this, ‘something’ will have to be spent. He connected
this idea to the idea of force cause. In 1842 Mayer put forward 2 questions,
what forces are and how they are related to each other. Mayer defended that
forces are causes as per prevailing idea in science at that time. For Mayer,
force disappears to make the effect. For example, weight was the cause of
falling in mechanics. According to Mayer, the cause of falling is not only weight,
but also the height of the body. By falling, the height decreases and the velocity
of falling increase. The meaning of force cause as given by Mayer is that the
‘force of falling’ diminishes and in its place another force ‘motion’ arises.
Joule (1843-1850) established the connection with the science of that time
through the concept of heat. There are two main thesis concerning the nature
of heat. According to Rumford (1798) and Davy (1799), heat was motion.
According to Carnot 1824) or William Thomson (1849), heat was a substance.
Some authors had posed the question, ‘what is heat?’ in connection with their
experimental works during the first part of the nineteenth century. Joule’s
research concerns these questions: heat is either a substance or motion. If heat
is a substance, its quantity cannot change. If this is not the case, then heat
cannot be a substance. If it cannot be a substance, it can only be motion,
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according to the science of that time. Joule’s experimental work aimed to show
that heat is not a substance. If it is motion then the question arose of how much
motion of mechanical character there must be in order to obtain a unit of heat.
This became then the main objective of his experimental work: the
determination of the mechanical equivalent of heat. He devised experimental
set ups.
Colding (1843-1856) aimed to prove his idea ‘forces of nature are
imperishable’. Observation shows that forces disappear. Colding had put
forward the thesis that they are not destroyed but transformed. The elements of
this transformation are observable, such as motion and heat. If what is given at
first, for instance motion is capable of being represented quantitatively by q, the
effect, for instance heat, must be equal to q. His experimental work
corroborates his idea in the following way: the more force that is produced, the
more that appears the force added does not disappear but becomes heat.
Helmholtz (1847) wrote a treatise on conservation of energy written in the
context of his medical studies. He discovered the principle of conservation of
energy while studying muscle metabolism. He tried to demonstrate that no
energy is lost in muscle movement, and there were no vital forces necessary
to move a muscle. Drawing on the earlier work of Carnot and Joule he
postulated a relationship between mechanics heat, light, electricity and
magnetism by treating them all as manifestations of a single force (energy in
modern times).
The term ‘energy’ meant activity and had been used with this meaning in the
18th century and in the first part of the 19th century. In1851, William
Thomson, later on Lord Kelvin, used the word to refer to the mechanical
activity of a body, i.e., its capacity of doing work. The division into two sets –
static and dynamical – of the stores of activity available led to the distinction
between potential and kinetic energy. Attempts made in order to adapt the
concept to phenomena led to the concept of energy as a substance. Energy
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was considered a substance towards the end of 19th century. This was the
reason for criticism and for some of the difficulties with the understanding of
energy. The variety of theses concerning the nature of heat, falling of bodies,
energy and the fact that these theses were used to explain phenomena
highlight an important characteristic of science: scientific theories include an
interpretation of phenomena. Present theses concerning heat, which is a form
of energy or transference of energy, force, which is the cause of acceleration
or a thing of thought and energy, which exists or is an abstracted concept,
help students to understand that such problems are not only from the past
and foster their thinking about science.
James P. Joule (1818-1889) determined energy equivalence of heat, and work
equivalence of electric energy (1 cal=4.184 J).
Max Planck (1858-1947) explained the energy aspect of light.
Albert Einstein developed the special theory of relativity and gave the energy
equivalence of mass, E = m c2 (rest mass of electron = 511 keV).
The recent statement about energy includes the following (Sefton. lan, 2000).
-
Energy is an attribute of a system which may consist of one or more objects.
-
Whenever the energy of a system increases (or decreases - there is a
corresponding decrease (or increase) outside the system, thus holding the
idea of conservation of energy as weak version.
-
There are only 2 basic kinds of energy, K.E and P.E
-
KE is associated with motion
-
PE is associated with interactions between objects
-
Electro-magnetic PE can be described as being stored in and transmitted by
electric and magnetic field.
Energy: The Subject Matter
Energy is in everything – it is often described as the ability to do work. Almost
all food energy comes originally from sunlight. The chemical elements that
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make up the molecules of living things pass through food webs and are
combined and recombined. At each link some energy is stored, but much is lost
along the way in the form of heat into the environment.
Some examples of energy use
-
When we eat food, our body uses (chemical) energy embodied in the food
to move around.
-
Most of the electricity produced in the world comes from the chemical
energy released in the burning of coal, oil or gas.
Science classifies energy into 2 categories.
Kinetic Energy
Potential Energy
Electrical energy- the movement of electrical
charges
Gravitational Energy
Radiant energy- electro-magnetic energy that
moves in waves. Visible light, X-ray and radio
waves
Elastic Energy
Sound energy
Chemical energy
Motion/kinetic energy
Nuclear energy
By nuclear fission and fusion
In physics, energy is an indirectly observed quantity that is often understood as
the ability of a physical system to do work on other physical systems. Since
work is defined as force acting through distance (a length of space) energy is
always equivalent to the ability to exert pulls or pushes against the basic forces
of nature along a path of a certain length.
The total energy contained in an object is identified with its mass and energy
cannot be created or destroyed. When matter (ordinary material particles) is
changed into energy such as energy of motion or into radiation), the mass of
the system does not change through the transformation process. However,
there may be mechanistic limits as to how much of the mater in an object may
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be changed into other types of energy and thus into work, on other systems.
Energy, like mass, is a scalar physical quantity, in the international system of
units (SI) energy is measured in joules, but in many fields other units, such as
kilowatt hours and kilocalories are customary. All of these units translate to
units of work, which is always defined in terms of forces and the distances that
the forces act through.
A system can transfer energy to another system by simply transferring matter to
it (since matter is equivalent to energy, in accordance with its mass). However,
when energy is transferred by means other than matter-transfer, the transfer
produces changes in the second system, as a result of work done on it. This
work manifests itself as the effect of forces applied through distances within the
target system. For example, a system can emit energy to another by
transferring (radiating) electromagnetic energy, but this creates forces upon the
particles that absorb the radiation. Similarly, a system may transfer energy to
another by physically impacting it, but in that case the energy of motion in an
object called kinetic energy, results in forces acting over distances (new
energy) to appear in another object that is stuck. Transfer of thermal energy by
heat occurs by both of these mechanisms; heat can be transferred by
electromagnetic radiation or by physical contact in which direct particle-particle
impacts transfer kinetic energy.
Any form of energy may be transformed into another form. For example all
types of potential energy are converted into kinetic energy when the objects are
given freedom to move to different position (as for example, when an object
falls off a support). When energy is in a form other than thermal energy, it is
theoretically possible to transform it with very high efficiency to any other type
of energy, including electricity or production of new particles of matter. (Exactly
100% efficiency is impossible only because of friction and similar loses). By
contrast, there are strict limits to how efficiently thermal energy can be
converted into other forms of energy, as described by Carnot’s theorem and the
second law of thermodynamics.
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Energy Concepts
1829 French Physicist Gustavo Coriolis
introduce the term ‘kinetic energy’
1843 James Joule’s experiments show
how heat, work and power are related
1847 Joule and German physicist Hermann von
Helmholez and Julius Meyer independently state the
law of conservation of energy
1853 Scottish scientist William
Rankine devises the concept of
potential energy
1881 The World’s first
electricity generating power
station opens in Surrey, UK.
1884 Irish Engineer Charles
Parsons invents the Steam
Turbine
1905 German physicist Albert
Einstein suggests that matter is a
form of energy, and vice versa
1980s Declining fossil fuel
reserves and pollution
bring calls for machines and
industries to be more
energy efficient
Fig. 5.1: Timeline – Energy
From the timeline of energy (Figure 5.1), it is evident that individual scientists
had understood and coined kinetic energy in the year 1829 and potential
energy in 1853. There was confusion as to whether energy was a substance or
merely the physical quantity.
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The experiments of Joule, Helmholtz and Mayer independently put all the
confusion regarding the physical nature of energy to rest. If energy was not a
substance then it could only be motion according to the science of that time.
Joule’s experimental work proved that a certain amount of motion is required to
obtain a unit of heat 1Cal = 4.184 Joules.
Scientific theories attempt to interpret phenomena. It is also evident that
theoretical aspect of energy was in scientific discussions for some time and
then experimentation proved the theoretical premise followed by mathematical
formula such as the formula propounded by Einstein. The relation between
heat, work, and energy, power and motion got established one by one.
Historically energy was thought as force till the time of Mayer and as a
substance till the end of 19th century. The simultaneous but independent work
of Joule, Mayer and Helmholtz established the law of conservation of energy.
Hence other forms of energy light, electricity, sound etc. were discovered.
Einstein suggested then that matter is energy and vice versa. Discovery of
many theories (aspects) of energy opened up other the technological
contributions like power stations, turbines and even nuclear energy.
From the study of the evolution of energy, the implications for school science is
that it is difficult to understand energy as a physical quantity till they understand
the effect of energy. They would probably understand phenomena related to
energy first, then understand the meaning of energy as the ability to do work
and then forms of energy. Conceptualizing conservation of energy and
transformation would be possible once students are ready to go beyond
observation of phenomena to explanation of phenomena (possibly by
theoretical aspects). The attention of students needs to be drawn to conceptual
explanation behind physical phenomena like water wheel, wind mill etc. The
discoverers of energy did not find anything that is indestructible, transformable,
but rather that the concept of energy underwent a change of meaning from
substance to a quantity.
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5.3. Pedagogical Perspective of the Concept: Energy
Energy is chosen as a focus of interest of most science curricula since it
provides key to our understanding of the ways things happen in physical,
biological and technological world. Moreover energy issues have personal,
social and environmental implications for students creating their interest in
learning. Understanding these implications is necessary for students to make
informed decisions concerning current situation. Sources of energy and energy
transformations are inter-related concepts and curriculum places emphasis on
the development of knowledge and attitudes in these areas. Energy as a
concept is problematic, not easily understood. Nobel laureate physicist Richard
Feynman during a 1961 lecture for undergraduate students at the California
Institute of Technology said this about the concept of energy: “There is a fact,
or if you wish, a law, governing all natural phenomena that are known to date.
There is no known exception to this law—it is exact so far as we know. The law
is called the conservation of energy. It states that there is a certain quantity,
which we call energy that does not change in manifold changes which nature
undergoes. That is a most abstract idea, because it is a mathematical principle;
it says that there is a numerical quantity which does not change when
something happens. It is not a description of a mechanism, or anything
concrete; it is just a strange fact that we can calculate some number and when
we finish watching nature go through her tricks and calculate the number again,
it is the same.”(Feynman Lectures) Earlier, researchers like Stead (1980),
Solomon (1980), Duit (1981), and Watts (1983) have been interested to
investigate into the frameworks of students’ and adults’ conceptions about
energy. The seven frameworks that were found useful as means of analysing
and describing the complex responses students provide as they discuss the
concept of energy are:
Human-centred models: Energy is associated with human beings;
Depository model: Some objects have energy and expend it;
Ingredient model: Energy is a dormant ingredient within objects, released by
trigger;
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Activity model: Energy as an obvious activity model;
Product model: Energy is a by-product of a situation;
Functional model: Energy as a general kind of fuel with making life comfortable;
Flow transfer model: Energy as type of fluid transferred in certain processes.
Later researchers using quantitative data also fell back on these frameworks.
Later researchers like Coehlo (2009), Lijnse(1990), María I. Cotignola (2002), et
al have attempted to find whether difficulties in learning energy concepts are
linked to the historical development of this field and also whether using
historical ideas in pedagogy helped in removing these difficulties.
Research shows that concepts based on singular ideas such as identifying an
energy source is easily understood by primary students. When students have
ideas about energy sources and transformation processes, they can learn
energy conservation by recognizing a system with various components. This
means that the learning progression/evolution of energy can be facilitated when
students can generate and connect ideas of sources of energy forms of energy
and transformation of energy. A highly integrated concept like energy
conservation may be difficult at the elementary level.
Researchers have investigated into students’ conceptions of energy using
techniques and tools according to various perspectives. From all the available
research in the area of elementary students’ understanding of energy concepts,
one can conclude that researchers have investigated on the sub-concepts of
fuels, renewable sources of energy, energy in living systems, forms of energy,
transformation and conservation of energy. Concepts about fuels of younger
students’ of class 3rd have been researched (Urevbu, 1984).Forms of energy
may be conceptualised in specific contexts by students of class 6th (Tsangliotis,
2005). Duit (1984) has studied the understanding of students of class 7th to 10th
about transformation of energy as well as conservation of energy. None of the
researchers have attempted to find the conceptualisation about conservation of
energy in elementary students except Duit (1984). The table below summarises
the sub-concepts chosen by investigators in research literature.
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Table 5.1: Investigators Studying Conceptions of Elementary Students about
various Energy Concepts
Sub-concepts of
Energy
Investigators
Class
III
Sources of EnergyFuels
Urevbu (1984)
Sources of EnergyPollution
Boylan (2008)
Sources of EnergyRenewable
Boylan (2008)
Sources of EnergyNon-renewable
Boylan (2008)
Energy in Living
Systems
Nicholls & Ogborn (1993)
Trumper (1993)
Sun as Ultimate
Source of Energy
Tsangliotis (2005):
transformation in specific
contexts of toys and
science fair, solar energy
and mechanical energy only
Energy and Work
Duit (1984)
IV
V
VI
VII
VIII
Tsangliotis (2005)
Forms of Energy
Duit (1984)
Transformation of
Energy
Tsangliotis (2005)
Duit (1984)
Different investigators have different opinion about inclusion of energy concepts
in primary or elementary curriculum.
According to Watt (1983) if youngsters are to be encouraged to undergo
conceptual change towards the scientific view of energy, then both the content
and practice of science education must change. Pupils' ideas must be valued
and built on. He recommends that both student and teacher need to find out
and to know both their own - and each others’ - meanings for energy.
Warren (1986) indicate that energy concepts should be taught only to students
of higher classes, who have developed a high level of abstract reasoning while
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Solomon (1986) claimed that teaching energy, should be started as early as
possible (as early as 3rd or 4th grade) to be encouraged to follow paths of
abstract conceptualization.
Duit, (1989) admits that the abstract nature of the energy concept makes it
difficult to understand. Furthermore, in the primary school education, some
aspects of teaching of ‘energy’ concept are controversial. For example, there
are such questions as “in which class?” and “at which level?” On the other
hand, in view of Driver and Warrington (1985) instruction of energy and related
concepts is difficult for primary school students, but yet those concepts should
be taught. Trumper (1993) argues for early teaching of the concept ‘energy’ to
lead eventually to necessary abstractions.
The typical teaching sequence for the energy concept has been determined
primarily through expert consensus by Liu and McKeough, (2005) based on the
data on TIMSS. This sequence is: (1) energy source, (2) work, (3) energy
transfer, and (4) energy conservation. It is expected that students will acquire
the concept of energy conservation during the high school years (American
Association for the Advancement of Science, 2001), and by the 8th or 9th
grade, students are expected to understand the concept of energy transfer and
the notion of energy as the ability to do work.
Dawson-Tunik (2005) is of the opinion that many ninth graders achieve neither
an understanding of energy as the ability to do work nor an understanding of
energy transfer at the conceptual level.
Hirca N. et al. (2008) found that many eighth graders cannot apply their
theoretical knowledge of types of energy to their daily life experiences, about
the same percentage of them is able to link type of energy plant absorbed with
photosynthesis. They concluded that the students had some difficulty not only
in understanding and correctly using of the concept of energy and the related
concepts, but also making a relationship between theoretical knowledge and
practical one.
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Summarising, the development of understanding energy involves understanding
many aspects of energy such as energy source, transfer, transformation, and
conservation. To be scientifically complete and sophisticated, understanding
should be based on energy as a conserved quantity. Students' overall
understanding can progress toward energy conservation by identifying energy
sources in a system and connecting various forms of energy and energy transfer
processes to changes occurring in the system. In addition, students should be
able to recognize and use energy concepts across mechanical, biological,
chemical, thermodynamic, and technological applications.
5.4. Development of the Concept Maps: Energy
Concept maps were developed to fulfil the following objectives: a) To
understand what the intended curriculum includes in the area of energy in
Indian context and b) To identify what constitutes ‘standard’/expected
knowledge in the area from available curricular resources and c) to derive a
concept map from the maps mentioned above to form a basis for developing
questionnaire.
Concept maps can be defined as visual representations that are added to
instructional material to communicate the logical structure of the instructional
material. The concept map serves as a device to illustrate the hierarchical
conceptual and propositional nature of knowledge. The concepts are arranged
in a hierarchy with a super ordinate concept at the top. The concepts are linked
by lines labelled with connecting words that form the proposition uniting the
concepts. Concept mapping requires the mapper to prioritise and make
judicious use of selected concepts when mapping. It involves identification
concepts in study materials and their organisation from the most to least
general, more specific concepts.
Concept maps are flexible tools that can be used in a variety of educational
settings (Stewart, Van-Kirk and Rowell, 1979).They have been used as a tool
for assessing meaningful learning(Novak,1979) as well as in curriculum
planning, instruction and evaluation( Stewart et al,1979).Concept maps are
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useful in science curriculum planning for separating significant from trivial
content (Starr and Krajcik, 1990) and focussing the attention of curriculum
designers on teaching concepts and distinguishing intended curriculum from
instructional techniques (Stewart et al,1979). Science education reforms have
developed concept maps to decide which concepts are the most important to
learn and use what are important concepts that contribute the big picture or
pervasive principles at the core of scientific disciplines. Science educators
extract, select and prioritize concepts from information-dense materials
(Jonassen, Biessner and Yacci, 1993). Science curriculum reforms in USA and
Australia are such cases and are being presented in the following paragraphs.
AAAS Project 2061 and the National Science Teachers Association published
two volumes of Atlas of Science Literacy. The two volumes include nearly 100
maps which chart all the learning goals specified in Bench marks essential for
every student to learn. The maps given in the Atlas of Scientific Literacy
illustrates the relationships between individual learning goals and shows the
growth of understanding of ideas. Connecting arrows indicate the connections
between ideas which are based on the logic of the subject matter (or on
cognitive research about how students learn).The maps are available at
http://www.project2061.org//tools//benchol/bolframe.html
The Department of Education and Early Childhood Development (DEECD),
State Government of Victoria, Australia has developed the science continuum
P-10 for effective science teaching. The Science Continuum P-10 identifies
focus ideas at each level of essential learning standards for science.
Connections between concepts and pathways of student’s concepts are
mapped in science concept development maps. The concept developmental
pathways are the ones students may take when developing scientific
understandings. They demonstrate the relationship between concepts, how
concepts contribute to a range of scientific fields and how concepts of
increasing complexity are developed from more simple understandings. The
concept maps are available at www.education.vic.gov.au/studentlearning/
teaching resources/science.
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The development of concept maps of Energy was taken up by analysing (a) the
Environmental Science Text books (class 3rd to 5th) and Science Textbooks of
NCERT (class 6th to 8th) and (b) International standards in science and other
curricular material available through web resources.
5.4.1. The Intended Concept Map: Indian Source
The intended curriculum or the prescribed curriculum designed by Educational
authorities in a country and is intended for the instructional guidance. In our
country NCERT is an apex body under the Ministry of Human Resource
Development (MHRD) which is responsible for preparing curriculum guidelines
for the entire country. It also develops and publishes text books based on the
guidelines prescribed in the National Curriculum Framework. Since education is
in the concurrent list, most of the states, develop their own curriculum based on
the national curriculum framework. Some of the states adopt the NCERT
textbooks translating it in regional languages (e.g. as in case of Delhi State)
and other states adopt them to suit their local contexts. With an experience in
the field, the researcher has found that private publisher or publishers of the
state board mostly develop text books in the same lines as the NCERT
textbooks and hence NCERT textbooks were selected as symbolic source of
intended curriculum in the Indian context The syllabus guidelines for
elementary classes for environmental studies (from class 3rd to class 5th) and
science (from class 6th to 8th) were looked into. At the primary level, science is
part of environmental studies and not as a separate subject. At the upper
primary level science is taught as a compulsory subject. The textbooks from
class 3rd to 8th and syllabus guidelines of elementary classes were analysed to
derive a concept map. The syllabus guidelines and textbooks are available at
www.ncert.nic.in. After Starr and Krajcik (1990), significant content was
separated from trivial content to focus the attention on teaching concepts and
distinguishing intended curriculum from instructional techniques (Stewart et al,
1979) to draw the concept map.
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The outline of the concepts and sub concepts of energy has been drawn in the
coming sections. To understand the placement and depth of the concepts in
each grade, the researcher (The energy concept has few strands at the
elementary level) identified the following:
•
Sources of energy : fuels, fossil fuels
•
Fuels & environmental consequences
•
Renewable sources of energy
•
Non-renewable sources of energy
•
Energy in the living system
•
Forms of energy
•
Transformation of energy
Each strand was traced in the context of all chapters presented in the textbooks
of Class III to VIII to trace the strands related to energy concept.
Energy as a scientific concept has not been introduced nor defined in the
present science content at the elementary school level (according to NCF
2005). Energy concept is used in several contexts such as energy to work,
energy from food, solar energy, and various forms of energy and sources of
energy in science text books. The context is mostly sources of energy at
elementary level. Sources of energy are placed under the theme of materials;
Forms of energy like heat, sound, light, electricity etc. have been included
without referring to these as forms of energy. Observable phenomena related to
heat, sound, light and electricity are only part of elementary science content.
Energy as a term has been used in science text books at elementary level to
refer to energy from food or energy from sun.
The sub-concepts which can be traced in elementary science curriculum in the
Indian context are related to:
•
Fuels, Class 3rd, Chapter-10, Fossil fuels-Class 5th Chapter-5
•
Renewable sources of energy, Class 3rd, Chapter-10
150
Fuel efficiency is calorific
value of a fuel
Increasing fuel consumption has environmental
consequence like global warming, acid rain
Global warming and acid rains are liked to
combustion of fuels
Uses of different
constituents of petroleum
By burning fuels, CO2 heat and light is produced
How coal beds were
formed? Coal as fossil fuel
We must try to reduce the amount of fuels to
conserve resources/reduce pollution
Energy from sunlight is
available indefinitely it is and
can be used to run some
device
How petroleum was formed
Some resources like fossil fuels are
not renewable or renew very slowly. It
will become difficult to obtain
Fuels used by vehicles like bus, bullock cart,
cycle, metro, truck, car etc. petrol. Diesel,
gas, electricity and animals
Fuels used at home cow dung cake,
kerosene, wood, gas, electricity and solar
energy.
SOURCES OF ENERGY
134
ENVIRONMENTAL CONSEQUENCES
OF ENERGY USE
Fig. 5.2: The Intended Concept Map on Energy – Indian Source (Developed by the Researcher)
151
•
Non-renewable sources of energy, Class 5th Chapter 12
•
Sun as the ultimate source of energy Class 5th Chapter 12
•
Different sources of energy and their environmental consequences Class
7th, Chapter-6 and Chapter 10-class 3rd
•
Different forms energy: light, sound, electricity, heat (Class 4th) Class 6th,
7th, and 8th.
Inter-linked concepts like work and energy, meaning of energy, forms of
energy, transformation of energy, conservation of energy usually part of
elementary school science are not part of the present science content. In the
present text books, the strand in concept energy is mainly energy resources.
Concept statements related to energy at elementary level sourced from
intended curriculum are (E.V.S Text Books, class 3rd to 5th; Syllabus for
Classes at elementary level, Vol-I, 2006, N.C.E.R.T and Science text books,
class 6th to 8th):
•
Fuels like cow dung cake, kerosene, wood, gas, electricity and solar energy
are used for cooking.
•
Fuels like petrol, diesel, gas, electricity etc. are used by vehicles/ means of
transport.
•
Some resources like fossil fuels are not renewable or renew very slowly. It
will become difficult to obtain if we use them excessively.
•
We must try to reduce the amount of fuels to conserve resources. That will
reduce pollution also.
•
Primary energy from sunlight is available indefinitely. It is and it can be used
to run some devices.
•
Petroleum, natural gas and coal beds were formed from organisms and
forests buried under the sea or soil millions of year ago which were
transformed by high temperature and high pressure under the layers of
sand and clay deposits (Partly in primary).
152
•
A number of useful products for industry and domestic purpose are
processed from petroleum and coal (fossil fuels)
•
By burning fuels, CO2, heat and light are produced.
•
Fuel efficiency is the calorific value of a fuel.
•
Increasing fuel consumption has environmental consequences like green
house effect, global warming and acid rain.
There are chapters on heat and temperature, sound, light and electricity in the
upper primary classes. These chapters are based on observable phenomena
related to the above topics, intended to be transacted through related activities
in the students’ context. There is no attempt to link heat, light, sound and
electricity with the strand of energy. The topics force, work and energy are
introduced at secondary levels in detail.
The concept map developed by the researcher to show the main concepts and
sub-concepts of Energy included at the elementary level is shown in figure 5.2.
5.4.2. The Intended Concept Map: International Source
There are several concept maps available in text books and websites (for example
http://schools.longman.co.uk/exploringsciencehowscienceworks/members/pdfs/sta
rters_plenaries_qca/7I.pdf) which show a hierarchical representation of the
concepts of energy along with connecting ideas. The researcher has developed
a concept map with connecting ideas from energy sources, sun as the ultimate
source of energy, energy in the living world, meaning of energy and
transformation of energy. It has more concepts compared to the concept map
developed from NCERT text books. Energy sources and energy forms and
transformations are the two major strands within energy depicted in the intended
concept maps from international sources. There are two maps available on
transformation of energy and sources of energy on the website of AAAS Project
2061 and the National Science Teachers Association (USA) and in their atlas of
Science Literacy as well as DEECD, State Government of Victoria, Australia.
153
Fig. 5.3: Concept Map – International Source
154
SUNLIGHT IS THE ULTIMATE SOURCE OF
ENERGY OF MOST OF THE ENERGY WE USE.
THE ENERGY IN FOSSIL FUELS COMES FROM
ENERGY CAPTURED FROM SUN LIGHT LONG
AGO
SOME
RESOURCES
ARE
NOT
RENEWABLE
OR
RENEW
VERY
SLOWLY. FUELS ACCUMULATED IN
THE EARTH WILL BECOME DIFFICULT
TO OBTAIN
HOW COAL BEDS AND PETROLEUM
POLLS WERE FORMED
ELECTRICAL
ENERGY
CAN
GENERATED FROM NUMBER
ENERGY RESOURCES
ENERGY FROM SUN (WIND AND WATER) IS
AVALABLE INDEFINETELY. SYSTEMS ARE
REQUIRED
TO
COLLECT
AND
CONCENTRATE THE ENERGY
ENERGY RESOURCES ARE
MORE USEFUL IF THEY
ARE CONCENTRATED AND
EASY TO TRANSPORT
WHEN SELECTING FUELS IT IS
IMPORTANT TO CONSIDER RELATIVE
ADVANTAGES AND DISADVANTAGES
BE
OF
PEOPLE HAVE INVENTED NEW WAYS OF
DELIBERATEDLY BRING OUT ENERGY
TRANSFORMATION USEFULL TO THEM
INDUSTRY, TRANSPORTATION, URBAN
DEVELOPMENT,
AGRICULTURE
AND
OTHER HUMAN ACTIVITIES ARE TIED TO
AMOUNT AND KIND OF ENERGY AVAILBLE
DIFFERENT WAYS OF OBTAINING
TRANSFORMING
AND
IDSTRIBUTING ENERGY HAVE
DIFFERENT
ENVIRONMENTAL
CONSEQUENCE
BY BURNING FUELS, PEOPLE ARE
RELEASING LARGE AMOUNT OF CO 2
INTO ATMOSPHERE. CHEMICAL
ENERGY IS TRANSFORMED INTO
HEAT ENERGY
ENERGY IS REQUIRED
FOR
TECHNOLOGICAL
PROCESSES
SUCH AS TAKING PART MOVING
AROUND AND COMMUNICATING
WHEN 2 OBJECTS ARE RUBBED AGAINST
EACH OTHER, THEY GET WARMER
SUNLIGHT IS USED TO RUN SOME
DEVICES
TRANSFORMATION OF ENERGY
WITHIN A SYSTEM USUALLY
RESULT IN ENERGY ESCAPING
INTO ENVIRONMENT
SOME PEOPLE TRY TO REDUCE THE
AMOUNT OF FUELS THEY USE IN ORDER
TO
CONSERVE
RESOURCES/REDUCE
POLLUTION
MOVING AIR (WIND) AND MOVING
WATER CAN BE USED TO RUN
MACHINES
PEOPLE BURN FUELS SUCH AS WOOD, OIL, COAL OR
NATURAL GAS OR USE ELECTRICITY TO COOK THEIR
FOOD
THE SUN WARMS THE LAND, AIR
AND WATER
Fig. 5.4: Concept Map on Sources of Energy – International Source (Developed
after AAAS-Atlas of Literacy, 1999)
155
5.4.3. The Derived Concept Map: Energy and Energy Resources
A concept map is developed merging the two- ‘sources of energy’ and ‘energy’
strands together from international sources and balancing it with the NCERT
map. An in-depth comparison of concepts, concept statements from the strands
of energy concepts were done from syllabus documents, text books, concept
maps, science education standards based on NCERT syllabus guidelines and
textbooks of elementary classes and the concept maps from the international
context show the following:
In the Indian context, a lot of importance has been placed on the contextual
knowledge on energy sources and the environmental consequences of different
sources of energy in all the elementary classes. The consequences of using
fossil fuels like acid rain etc and the need to conserve non-renewable s at the
primary level point to the science society dimension in the curriculum.
At the upper primary level, phenomena related to different forms of energy like
light, sound, heat, electricity, magnetism are dealt in-depth without linking the
phenomena to energy. The content has been organized to emphasis on the
process skills of observation, manipulation of equipments, tabulation and
drawing inference to enable students to learn ‘how to learn’ for themselves
beyond school.
At the primary level, students’ attention has been drawn to different renewable
sources of energy that are used in their own context ranging from cow-dung
cakes to fossil fuels and a comparison has been drawn with sun and wind as
renewable source of energy. The advantages and disadvantages of renewable
and non-renewable sources of energy have been dealt with in the immediate
context of the child like drying things in the sun etc. The need to conserve
fossil, fuels has been dealt while presenting about oil wells and how petroleum
was formed and the rising prices of petroleum products (under the theme of
travel). As idealized by the policy of constructivism, it is expected that children
learn more about the topics from teachers and elders by scaffolding.
156
Transformation of energy takes place between
one form to another form of energy
Kinetic
energy
Potential
energy
Chemical
energy
Electrical
energy
Light
energy
Heat/Thermal
energy
Sound
energy
There are forms of
energy
Is the ability to do
work
Biochemical
energy in plants
Meaning
Most sources
are derived
from sun
Biochemical energy
in animals
Energy
Can be derived
from
Sources of
energy
Sunlight is the ultimate
sources of energy
Example
Renewable
sources
Non-Renewable
sources
Nuclear energy
Geo-thermal energy
Hydro-electric energy
Solar energy
Bio-mass energy
Wind energy
Petrol
Diesel
L.P.G.
C.N.G.
Energy in fossil fuels
comes from sun
Most sources except
biomass has less
environmental
consequences
Fossil
fuels
Fig. 5.5: Derived Concept Map – Energy (Developed by the Researcher)
157
The derived concept maps from the international context shows that the
concept of energy starting from the phenomena of heat has been dealt till
transformation of energy at the elementary level. The concepts and sub
concepts are scientifically stated. With standards movement in countries like
USA, UK, Australia, New Zealand, there is focus on scientific literacy (Duit,
2007) of students. Science curriculum are presenting hierarchical progressions
in a topic which follow are another as children learn about and investigate in a
broad span of 6-8 years (Ducshl et al 2007). The energy concept also has been
presented starting from sources of energy & forms of energy in the child’s
context to the various forms of energy which people use and the transformation
of energy from one form to another in different systems. The AAAS, 2061
science literacy maps present two maps on energy: one on transformation of
energy and one on energy sources. The researcher has derived a map based
on all these maps and developed a map which takes care of centrality of the
concept of energy and also the conceptual resource in terms of curricular input
to Indian elementary students.
The concept statements related to energy and sources of energy in the derived
concept map developed by the researcher for elementary classes are as
follows:
•
People burn fuels such as wood, oil, coal or natural gas or electricity to cook
their food.
•
When fuels such as wood, oil or coal are burnt large amount of CO2 is
released into the atmosphere.
•
Some fuels release less CO2 (for example natural gas) compared to wood,
oil and coal.
•
Oils and coals are fossil fuels which were formed thousands of years ago
because of decomposition reactions of submerged plants and animals.
•
Fossil fuels are taken from oil wells or coal mines with difficult extraction
procedures.
158
•
Once taken out, fossil fuels are not formed again and the reserves will get
exhausted. Hence they are called non-renewable or exhaustible energy
sources.
•
People are harnessing alternate sources of energy like solar energy, wind
energy, geo-thermal thermal energy, energy from bio-mass consisting of
plant products, bagasse and garbage. These are renewable sources of
energy.
•
Sun is the ultimate source of energy. Most of the energy we use food,
biomass, energy is fossil fuels, wind energy come from energy captured
from sunlight.
•
Energy is the ability to work. Energy is required for cooking, moving around,
and other technological processes.
•
Energy appears in different forms.
-
Motion energy is associated with the speed of an objection.
-
Thermal energy is associated with the temperature of an object.
-
Chemical energy is associated with composition of a substance.
-
Electrical energy is associated with electric current in a circuit.
-
Light energy and sound energy are two other forms of energy we are
familiar with.
•
Different forms of energy can be transformed from one form to another.
•
When you switch on a tube light, electrical energy is transformed to light
energy.
•
When you run around chemical (bio-chemical) energy of the food is
transformed to (mechanical) kinetic energy of motion.
•
Chemical energy of the fuels is transformed to kinetic energy of vehicles.
•
Light energy of sun is transformed into food during photosynthesis lay
plants.
159
5.5. Students’ Conceptions of Energy: Primary Source
In the first section, scientific perspective has been explored via the path treaded
by scientific community for over two hundred years during which the content
area of energy was unraveled. This exercise helped the researcher to know the
‘big’ ideas and the strands within the content area of energy. It is imperative to
know the conceptual resources present with the students for whom the big
ideas are meant. Pedagogical perspective of energy concepts was built by
reviewing the research literature about students’ understanding of energy
concepts. The existing intended curricula in the Indian and international context
were analysed to comprehend the coverage and depth of the ideas about
energy meant for elementary students. From this understanding, a derived
concept map on energy was developed on the basis of which questionnaires
would be developed. The purpose of this part of the study is:
-
to identify the conceptual ideas of students in energy from class 4th to 8th
-
to explore whether there is progression from contextual knowledge to more
scientific understanding
-
to explore the trajectory of students from phenomenal knowledge to
conceptual understanding.
Tool Development
The outlines of the energy concepts were divided into 6 sub-concepts such as
understanding of fuels, renewable and non-renewable sources of energy,
sources of energy and pollution/ environmental consequences and energy in
living systems, meaning of energy and energy transformations. Several
questions were framed on each sub concept keeping mind the concept behind
it and the learning performance in terms of identifying examples, differences,
definitions, meaning or finding relation etc. For example: which of the following
is different compared to the other three: diesel, coal, wind and petrol. Relevant
research studies were scanned to search for appropriate assessment items that
could reflect students’ thinking. These items were then converted into multiple
choice type items by introducing suitable distracters on the basis of learner’s
160
responses during interaction with them. The questions thus formulated were
ratified through expert opinion and placed in a questionnaire. These questions
were piloted in a school with around 40 students in each class from class 4th to
8th. The responses on this set of questions were analyzed. The discrepancies
in language were removed. Minor modifications were made on the basis of
whether or not the content of the modules was comprehended by the students.
Sample
The sample for collecting date from primary source constitutes approx 200
students across each class from Class IVth to Class VIIIth from 5 schools of
Delhi, 2 of which were Kendriya Vidyalayas and 3 were Public Schools of Delhi.
The purpose of choosing the Kendriya Vidyalayas was that they represent the
government set up with students from diverse socio-economic and linguistic
backgrounds. The 3 Public Schools cater to a similar clientele and also have
similar infrastructural and instructional facilities and all five schools were
affiliated to the CBSE & hence have similar curricular exposure.
Tool
The questionnaire on energy has 2/3 questions each on the concepts of related
to their understanding of fuels, renewable and non-renewable sources of
energy, sources of energy and pollution/ environmental consequences and
energy in living systems, meaning of energy and energy transformations . While
younger students were asked more about sources of energy and energy in
everyday context, older elementary students were probed with questions on
sources of energy along with questions about energy transformations. There
are overall 13 questions in the questionnaire on energy for the students of three
stages (Appendix-A, B and C). Questions were placed within two strands: (i)
sources of energy and (ii) energy: meaning, forms and transformations.
Analysis Design
The responses of students were analysed to see a general picture of
elementary learners’ conceptions about energy and difference among stages
from mean, standard deviation, and applying one way ANOVA with 3 groups
161
(stage 1, 2 and 3) and chi-square test of significance. Difference within the
stage that is between classes 4th and 5th and between 6th and 7th were also
tested for significance by chi-square test for all questions and also between
stages for select questions which were asked across stages. Percentage of
responses, difficulty value of questions (hence concepts) were analysed to see
if learners’ conceptions progress within the strands. Wherever students of
different stages were presented with the same question, data was presented
through graphs and difference was tested for significance by chi-square test
and difference if any is indicated in the following section where individual
concepts are dealt.
5.5.1. General Analysis of Students’ Conceptions about Energy
The central tendency through mean and distribution of scores (standard
deviation, and range of scores) were analysed to find the general
understanding of students in energy. The central tendency of a distribution is an
estimate of the centre of a distribution of values. The mean or average is the
most commonly used method of describing central tendency. To compute the
mean all the values were added up and divided by the number of students.
The mean of the students’ understanding in the questionnaire on energy and
standard deviation across the three stages is as follows:
Table 5.2: Mean and S.D. across Stages
Energy
Stage-1
(N=401)
Stage-2
(N=360)
Stage-3
(N=196)
Mean
47.33
60.88
60.01
Standard Deviation
16.02
19.95
14.96
The overall impression showed that there is trend with a dip at the end of the
progressive line. Stage3 and stage 2 have similar understanding of the energy
concepts asked and stage 2 and 3 have better understanding than
stage1(Table 5.2).The pilot study had not accounted for such trend which
appeared in the main study.
162
One-way ANOVA was used with the three groups of students, stage 1, stage 2
and stage 3 to investigate statistical differences among them. The statistical
results were interpreted only if the data met a basic assumption for the use of
ANOVA, i.e. the variances of three groups were similar (homogeneity of
variance). As shown in Appendix E, the quantitative data results indicate there
are
statistically significant differences
among three
groups
on
their
performances in the energy, F (2,954) = 44.07, p < 0.05. The stage 3 (N = 196,
Mean = 60.01, S.D = 16.68) and stage 2 (N = 360, Mean = 60.88, S.D = 28.2)
outperformed the stage 1 (N = 401, Mean = 47.34, S.D = 16.03). There is a
significant difference between the stage 2 and stage 1 on their performance
and between stage 3 and stage 1. But there is no significant difference in the
performance of stage 2 and 3. The two groups, stage 2 and 3 are
homogeneous.
The data indicate that as students progress through the science curriculum
from primary to middle level, there is a progression in their knowledge about
energy.Stage1, 2 and 3 had studied more about energy sources than about
energy. Cognitive maturity of stage 2 and 3 appears to shift their understanding
about energy towards progression. A bigger sample with a full range of
questions on energy may help to make more definitive conclusions.
Since the purpose of present research is to find the concepts which are
conceptualized by learners easily or with difficulty, a simple difficulty value was
computed. The concepts with 0 to 0.40 Difficulty values (D.V.) were considered
difficult, concepts with 0.41 to 0.60 D.V. were considered as having average
difficulty, and concepts tested with 0.61 D.V. to less than 1 were considered
easy. The questions asked were not instruction/curriculum based; hence a
large value (of 0 to 0.4 or 0.61 to 1) was allocated not to lose any valuable data.
From the table 5.3, it can be inferred that younger students of stage 1 found
more concepts difficult compared to students of stage 3.
163
Students of all the 3 stages found sources of energy, fuels & thermal
energy concepts easy. Form of energy related to students’ experience were
conceptualized by students of all 3 stages & were of average difficulty for all.
Concepts related to meaning of energy, form of energy, transformation of
energy & nuclear source of energy were found difficult by all.
Table 5.3: The Difficulty Continuum of Energy Concepts across Stage 1, 2 & 3
D.V.
Easy
(0.61 to
< 1)
concepts
Stage 1
- Fossil fuel
- Thermal energy
- Identifying renewable
among nonrenewable source of
energy
- Heat changes water to
vapour
- C.N.G. less polluting
is
- Source of energy for
man source of
energy for tiger
Average
0.60 –0.41
Stage 2
- Source of energy for man
Stage 3
- Form of energy is
human body
- Form of energy change
when bell rings
- Source of energy for
predator
- Heat changes water to
vapour
- Light energy is captured by
plants in photosynthesis
- Identifying renewable
source among nonrenewable
- Meaning of fuel
- Electricity as a form
of energy
- Moving objects have kinetic
energy
- Transformation of
energy in a solar cell
- Moving objects have
energy
- Source of energy heats
both solar cooker & gas
store
- Reactions converting
organic material into
petroleum
- Transformation in motor
cycle engine
- CNG as producing less
CO2.
- Maximum Energy is used in
heating a room
- Problems with burning
of coal
- Solar energy stored in
Biomass
Difficult
0.44-0.0
- Meaning of
renewable energy
source
- Form of energy in human
body chemical. energy
- Energy not derived from
sun
- Meaning of energy
- Source of energy in
a solar cooker
- Transformation of energy a
flashlight
- Uranium as source of
energy
- Form of energy in
electric cell of a
battery
- Energy level after
exercise
- Meaning of Energy
164
- Transformation of
energy in flashlight
From this study of elementary students’ conception about energy and energy
sources, it was found that students of stage 1 find 7 concepts out of 12
concepts, difficult (item difficulty / percentage responses show it). Two of these
concepts are related to forms of energy, one is related to renewable source of
energy and one is related to identifying the source of energy in a solar cooker.
Their exposure to the topic in curriculum seems to have marginal effect on
them. They also found the conceptualisation of energy levels in our body in
relation to exercise and the definition of energy to be difficult. However,
students of class 5th identify forms of energy better than class 4 students.
Students of stage 1 could conceptualise about sources of energy better than
about forms of energy or meaning of energy etc.
Students of stage 2 found four concepts difficult (below 40% correct response).
These students find concepts related to sources of energy, forms of energy and
meaning of energy difficult. Sources of energy is conceptualised easily by older
students. Their conceptualisation about sources and forms of energy is better
than the students of stage1. Transformation of energy from one form to another
is not understood by most of the stage2 students. Most students of this stage
had conceptualised about sources of energy and thermal (heat) energy well.
The students of stage3 have conceptualised most concepts related to energy
inquired of them. They had difficulty in conceptualising 3 concepts. These are
related to the transformation of energy in a flashlight, 2 questions related to
nuclear energy. Conceptualisation of it will require understanding of forms of
energy in various contexts and the transformation of energy from one form to
another. However, around 19% of students intuitively understood the concept
of transformation. They could have used their conceptual understanding about
conventional sources and answer about nuclear energy. But the students were
awed by a new term Uranium/ nuclear energy introduced. Concepts on forms
of energy and sources of energy were easily understood by most of the class
eighth students.
The possibility of progression of elementary learners within sub-concepts is
analysed and interpreted in the following section.
165
5.5.2. Comprehensive Analysis of Students’ Conceptions about Energy
The development of energy understanding involves understanding many
aspects of energy such as energy source, forms of energy, transfer,
transformation & conservation (Lee and Liu, 2009). In this research, it would be
investigated if the energy concept sequence is supported by student responses
to items addressing energy placed within two strands: (i) sources of energy and
(ii) energy: meaning, forms and transformations.
Distracter analysis was done to find percentage of responses of each concept
asked. Students’ responses were analysed to find whether they corresponded
to scientific conceptions or alternate conceptions.
Scientific Conception – The term ‘scientific conceptions’ refers to those ideas
about a particular concept or subject that are presently shared by the scientist
community. The use of the term ‘scientific conception’ instead of the ‘correct’
conception is depictive of the dynamic nature of science and allows scope for
the possibility of revision of scientific knowledge which is how the disciplinary
knowledge develops.
Alternative Conception – The term ‘alternative conceptions’ in this study refers
to all ‘ideas which differ significantly from the accepted scientific view (Gilbert,
1983) of this day. In the present study the term ‘alternative conceptions’ may
include within its purview:
-
Pre-conceptions that have survived formal instruction
-
Hybrid conception resulting from the interplay between formal and pre
conceptions. These may not be entirely incorrect ideas but may incorporate
some correct ideas as well.
-
Limited conceptions.
Distracter analysis was done to find percentage of responses for each concept
asked. Chi-square test of significance for all questions on energy between
166
classes 4th and 5th reveals that all 12 questions except 3 questions showed no
significant differences. Those 3 questions have been indicated for the
difference in the following section. The chi-square test shows that classes 4th
and 5th are more homogeneous and it is logical to include them in one stage,
i.e. stage 1.
Chi-square test of significance for all questions on energy between classes 6th
and 7th reveals that all 11 questions except 1 question showed no significant
differences. That 1 question has been indicated for the difference in the
following section. The chi-square test shows that classes 6th and 7th are more
homogeneous and it is logical to include them in one stage, i. e stage 2.
On the basis of responses, students’ conception about energy was summarised
as follows.
5.5.2.1. Students’ Conceptions about Sources of Energy
There are 7 questions on sources of energy in the questionnaire meant for
students of stage1 and 3 questions in the questionnaire for students of stage2
and there are 5 questions in the questionnaire meant for students of stage3 on
the same topic (Appendix A, B and C). The questions were related to their
understanding of fuels, fossil fuel, renewable and non-renewable sources of
energy, sources of energy and pollution/ environmental consequences and
energy in living systems and sun as the ultimate source of energy. Tables 5.4
to 5.8 present elementary students’ conceptions about energy sources.
Table 5.4: Students’ Conceptions about Fuels
Stage 1
Concept
Identification of fossil
fuel
Class IV & V
Age 9 to 10, N=401
Scientific Concept
Alternative Concepts
Coal is a fossil fuel 68%
167
Wood is a fossil fuel 11%
Chicken is a fossil fuel 12%
Wind is a fossil fuel 7%
Table 5.5: Students’ Conceptions about Fuels
Stage 3
Concept
Substance producing a lot of heat
on burning is called ___________
___________reactions transform
organic material into petroleum
Class VIII
Age 13, N=196
Scientific Concept
Alternative Concepts
Substance producing a lot
of heat on burning is called
Fuel 67%
Substance producing a lot of
heat on burning is called
Bio-gas 19%
Substance producing a lot of
heat on burning is called
Oxidizing agent 8.7%
Substance producing a lot of
heat on burning is called
Bio-mass 2.6%
Decomposition 67%
Elevated temperature 14%
Solar energy 8%
Hydroelectric energy 6%
Students of stage 1 (ages 9 to 10) were asked to identify fossil fuel among four
things of which 3 were sources of energy and one was chicken (Table 5.4).
Around 68% of stage 1 student understood coal as a fossil fuel. While 55% of
the class 4th students identify coal as fossil fuel, 81% of class 5th students
identified correctly. Wood as a fuel was understood by 11% of the students.
The rest 19% were not able to recognize the term ‘fuel’ that marked chicken
and wind as fossil fuel. The concept of fossil fuel is introduced in class 5th.
While an overall 68% of stage 1 students have been able to identify coal as
fossil fuel which is an important non-renewable source 19% do not understand
the meaning of fuel.
Students of class 8th were required to identify fuel as the substance which
gives a lot of heat on burning for which around 67% of students identify
correctly (Table 5.5). It is a part of content of their science text book. Around
19% of students thought bio-gas was the substance which gives out heat. Their
conception is specific and focus not generic.
Students of 8th class were required to identify the process which transforms
organic material into petroleum (Table 5.5). Almost 67% identify the process
scientifically as decomposition, 14.3% also thinks that the transformation is
168
due to elevated temperatures. This topic is part of textbook content of class
8th. Table 5.5 shows percentages of students’ responses to these 2
questions.
Gillian Nicholls and Jon Ogborn (1993) investigated into basic dimensions of
thinking which may underlie British children's conceptions of energy, and
attempted to detect changes in the dimensions, as a result of teaching. One main
dimension which emerged was the source — user distinction, with natural
phenomena and fuels seen as sources, and living things and energy‐using
devices seen as users. A second, more complex dimension was interpreted as a
distinction between acting alone versus being used to act. Natural phenomena
and living things are seen as the first, and fuels and energy‐using devices as the
second. The second distinction seems to be eroded by teaching but the first is
maintained.
Table 5.6: Students’ Conceptions about Renewable Source of Energy
Stage 1
Concept
___________ is a
renewable energy
source
Class IV & V
Age 9 to 10, N=401
Scientific Concept
Alternative Concepts
Wind 37.5%*
Petrol 9.5%
Diesel 12.9%
C.N.G. 34.8%
* Significant difference detected: Chi-square statistic=16.47, df =4, p<0.05.
Students of stage 1 were asked to pick a renewable energy source among 4
sources (Table 5.6). They were required to know the meaning of renewable
source to pick the correct option of wind energy from three other non-renewable
sources of energy. About 31% of class 4th and 45% of class 5th recognized
wind energy as renewable energy resource. A large percentage of students of
both classes thought that CNG is a renewable energy source.
169
Table 5.7(i): Students’ Conceptions about Source of Energy and Environmental
Consequences
Stage 1
Concept
Pick renewable
energy source
from other 3
non-renewable
energy source
Stage 3
Class IV & V
Age 9 to 10,
N=401
Class VIII
Age 13,
N=196
Scientific
Concept
Alternative
Concepts
Scientific
Concept
Alternative
Concepts
Wind 74%*
Diesel 9.7%
Petrol 3.7%
Coal 8.4%
Wind 90%
Diesel 3.6%
Petrol 2 %
Coal 4.6%
* Significant difference detected: Chi-square statistic=22.88, df =4, p<0.05.
100
90
90
80
82
Percentage
70
60
66
50
40
30
20
10
0
Class 4th
Class 5th
Class 8th
Fig. 5.6: Identification of Renewable Sources
Students were required to identify a renewable energy source from three nonrenewable sources as an odd one out question. Around 66% of the class 4th
and 82% of class 5th (and hence 74% of Stage 1) students identify that wind is
a different source of energy from 3 other non renewable sources. The increase
for class 5th is 16%, 82% of class 5th students identify correctly. On being
asked the same question, about 90% of Class 8th students easily identify
170
renewable source of energy -wind amongst 3 other non-renewable sources
(Table 5.7 and Figure 5.6).
Table 5.7(ii): Students’ Conceptions about Source of Energy and Environmental
Consequences
Stage 1
Concept
Source of energy causes
less air pollution
Class IV & V
Age 9 to 10, N=401
Scientific Concept
Alternative Concepts
C.N.G. 59
Petrol 16%
Coal 12%
Kerosene 12%
Students of stage 1 were asked to identify a source of energy which is less
polluting among coal, CNG, petrol and kerosene. Table 5.7 (ii) about 59% of
stage1 students identify CNG as a source of energy which is less polluting.
About 40% of stage 1 does not understand the relation between source of
energy and pollution; they pick petrol, kerosene and coal as less polluting
source.
Table 5.7(iii): Students’ Conceptions about Source of Energy and Environmental
Consequences
Stage 3
Concept
Class VIII
Age 13, N=196
Scientific Concept
Alternative Concepts
___________ are the
problems associated
with burning of coal
All of these 54.6%
CO2 emission
17.3%
Ash 14.8%
Acid rain 9.2%
___________ fuel
produces least CO2
per unit of energy
Natural Gas 61.2%
All these produce
some amount of
CO2 15.3%
Coal 5.1%
Oil 11.2%
___________ source
of energy does not
produce CO2
Uranium 17%
Natural Gas
54.6%
Coal 14.8%
Oil 9.2%
For a question on fuel and pollution, students of stage 3 are required to identify
the problems associated with burning of coal, almost 55% identify all the
171
problems together associated with burning of coal as acid rain, CO2 emission
and ash, rest 45% identify the problems but individually.
Almost 61% students of this stage identify that natural gas produces least
amount of CO 2 per unit of energy among coal and oil, hence same 39% of
class 8th students do not understand the relation between source of energy
and pollution.
To the question which energy source does not produce CO2, only 17% of stage
3 understood Uranium as the source and 55% picked natural gas as the
choice. Students misinterpret the advantages of natural gas. Most students do
not have the concept of nuclear energy. Refer to table 5.7(iii).
Table 5.8: Students’ Conceptions about Source of Energy
Stage 1
Concept
___________
gives energy/
heat in a solar
cooker
Class
IV & V
Age 9 to 10,
N=401
Scientific
Concept
Alternative
Concepts
Radiation
from sun
36.7%
Mirror 31.2%
Surrounding air
14.3%
Vessels 15.2%
Stage 2
Concept
___________
heats both
solar cooker
and gas stove
Class
VI & VII
Age 11 to 12,
N=360
Scientific
Concept
Alternative
Concepts
Source of
energy
heats both
44.4%
Sun heats 10%
Gas heats 24.6%
A chemical heats
16%
From the photographic image of a solar cooker, students of stage1 had to
identify its source of energy, the image being provided in case students have
no awareness about a solar cooker. Around 32% of class 4th and 41% of class
5th students identify solar radiation as the correct source. A higher percentage
of class 4th students think mirror in the cooker is source of energy. In 5th also
about 27% thinks it is the mirror. From the high percentage of responses to all
distracters it seems that a high percentage of students are not able to identify
the source of energy for a solar cooker (Table 5.8).
Tsangliotis N.L. (2005) of University of Crete, Greece inquired into 6th grade
primary school children’s conceptions about aspects of solar energy and their
change before and after teaching interventions of 10 teaching hours including
172
activities and practical investigations and preparing for a science fair on solar
energy. The main focus was to provide insights into a particular teaching and
learning environment. Students’ drawings and interviews were used to
understand aspects of conceptual change about solar energy with 11-12 year
old children in a primary science classroom in Greece. While students had
concepts about properties of solar energy like sun heats up things, gives light
and after the intervention they had ‘multiple varied conceptions’ about leakage
or waste of heat, and energy transformations involving solar energy. Their pre
and post conceptions seemed context dependent.
Students of stage 2 had to identify that a source of energy heats a solar cooker
and a gas stove as a common explanation (table 5.8). Around (44.4% of stage2
students) 38% of class 6th and 51% of class 7th understood the source of
energy correctly. About 24.6% thinks that gas heats a solar cooker as well as
gas stove. Papadouris et al (2008) explored the ways students aged 11-14
accounted for changes in physical systems involving energy and the extent to
which students drew on energy model as a common framework through
interviews and written questionnaire administered to 240 students from primary
and middle classes. They found that 38% of primary and 61.5 % of middle
students drew on the energy model to explain change in two different instances
like in the working of wind mill and electric fan and hence their responses were
conceptually oriented. Around 26% of primary and 21% of middle students also
gave conceptually orients responses but were drawing on other concepts of
physics like force or electricity. Around 29% of primary and 21% of middle level
students had a phenomenologically (at the level of observation) oriented
response. These later group attributed the cause for change towards certain
objects like electric wire or some processes of the system instead of a concept.
The researchers found that physics instruction and maturation had no bearing
on the students’ coherence of the energy model.
In tables, 5.2 to 5.7(iii) items require elicitation of single ideas and thus at lower
levels of knowledge integration. They are easier to solve than other questions
which require connections among multiple ideas. Only 2 items had less pass
173
percentage than 40.More than 60%. Students of stage-1 do not know the meaning
of renewable sources of energy, though they are able to pick non-renewable
source of energy among renewable sources. Renewable and non-renewable
sources of energy are part of instruction in class 3rd and class 5th as per the
syllabus guidelines (NCF 2005). For concept related to energy sources, scientific
understanding of students ranged from a mere 17% to 90%. Students of (Class
8th) stage 3 were not able to integrate their understanding about organic or
hydrocarbon fuels which produce CO2 in varying amount. Uranium, a nuclear
energy source does not produce any CO2 & students could not conceptualise this.
In table 5.8, responses of students of stage 1 & 2 are depicted. Both the
questions (Table 5.8) required conceptually oriented explanation of the energy
model and not elicitation of single idea from energy concepts. About 37% of
students had the conceptual understanding of identifying the source of heat in a
solar cooker. More than 60% of the stage-1 students are not able to identify the
source of heat in a solar cooker. The solar energy as an alternative to
conventional sources of energy is part of instruction in class 5th.
Discussion: The concept related to sources of energy are related to the context
of students’ experience and easily understood compared to the forms of energy
or transfer of energy. The science instruction does not prepare most of the
students to see beyond phenomena and understand the conceptual explanation
of the phenomena. This is corroborated by Papadouris’ et-al (2008) study.
Table 5.9(i): Students’ Conceptions about Energy in Living Systems
Stage 1
Stage 2
Class
IV & V
Age 9 to 10, N=401
Class
VI & VII
Age 11 to 12, N=360
Scientific
Concept
Alternative
Concepts
Scientific
Concept
Alternative
Concepts
________ is a
source of energy
for man
Food 75%
Water 19.1%
Car 2%
T.V. 1.5%
Food 70%
Water 18%
Car 6.2%
T.V. 4%
________ is the
most appropriate
source of energy
for tiger
Herbivore
animal
75%
Sun 2.1%
Heat 2.8%
Grass 6%
All of the above 13.2
Herbivore
animals 72%
Sun 4%
Heat 1.6%
Grass 5.6%
All of the above 15%
Concept
174
90
80
70
77
73
71
69
60
50
40
30
20
21.5
17
10
18
18
Class 6th
Class 7th
0
Class 4th
Class 5th
Source of energy for man-food
Source of energy is water
Fig. 5.7: Source of Food
Students of classes Stage 1 and Stage 2 were put the same question in which
they were required to identify source of energy among other things including
water and food table 5.9 (i). About 77% of class 4th and 73% of class 5th
understand that food is source of energy for man (Figure 5.7). Around 69% of
class 6th and 71% of class 7th identify food as source of energy for man, but
18% also think that water is a source of energy. There is no change in
percentage of response in students about food being source of energy for us
from class 4th to 7th. Their misconception about water also remains from
class 4th to 7th.
Around 17% students of class 4th, 22% of class 5th, and 18% each of class
6th and 7th think water is a source of energy. This relates to the previous
section on Food and Nutrition where in the classification task, about 45%
stage 1 students conceptualised
of
water to be food. Above 70% students of
stage 2 consider water to be food because water is necessary for plants and
animals. Text books present water as a component of food while some
nutrition specialists consider that organic substances only can be food.
Research on Nutrition by Project 2061(American Association for Advancement
175
of Science, AAAS, 1993) report that lower elementary school children may
believe that food and water have equivalent nutritional consequences.
About 72% - 77% of students of class 4th and 5th understand that food is a
primary source of energy for a tiger. About 13% -14% also understand about
the indirect source of energy like the sun, grass etc. In stage1 and 2 students
are attempting to conceptually explain energy source of predators other than
their food (.i.e. herbivore). They have begun to conceptualize the need and
dependence of predators (secondary consumers) on sun and grass apart from
their food i.e. primary consumers (deer in the response)
90
80
70
60
50
40
77
72
72
72
30
20
10
14
13
13.4
17
Class 4th
Class 5th
Class 6th
Class 7th
0
Energy for Predators food
Energy for Predators through food chain
Fig. 5.8: Energy for Predators
About 72% of students of stage 2 understand that food is a primary source of
energy for a carnivorous animal like tiger. But 14% to 17% also understands
the indirect source of energy like the sun, grasses etc. 14% of stage 1 students
also understand about the indirect source of energy. Students are starting to
understand the link between grass, deer and tiger through the food chain. In
their informal discussions, students mentioned about other sources of energy
needed apart from food.
176
Humans and other animals obtain their energy from plants. These plants and
their products are called ‘nutrition’ which are ‘energy store’. Hirca N., Calik M.
and Akdeniz F. (2008) investigated 171 grade 8 students’ (from 9 schools of
Turkey) understanding of ‘energy’ concept. They found that a significant
proportion of the students (58%) did not comprehend that humans and animals,
which burn food by using oxygen, get the energy in the nutrition by respiration.
Nearly four fifths of them did not understand the energy relationship among the
sun and plants and animals.
Colin Boylan (2008) conducted a research on 132 elementary students (mainly
class 3rd to 6th) of Australia regarding their understanding of energy and climate
change concepts. About 34% elementary students had the understanding that
eating food gives us energy, and 38% of them thought sleeping gives us energy
and 28% thought that the energy in our bodies comes from drinking water.
In the present study, around 19% elementary students have the concept that
water is a source of energy for man. So relatively less % age of students in our
context have the alternative concept.
Table 5.9(ii): Students’ Conceptions about Energy in Living Systems
Stage 2
Concept
Form of energy
produced in
human body
is ________
Stage 3
Class VI & VII
Age 11 to 12, N=360
Class VIII
Age 13, N=196
Scientific
Concept
Alternative
Concepts
Scientific
Concept
Alternative
Concepts
Chemical
Energy 37.4%
Pressure 32.6%
Friction 23.2%
Light Energy 4%
Heat Energy
63.3%
Force 21%
Pressure 9.2%
Light Energy 3.1%
Around 37.4% of stage 2 (42% of 7th class students and 33% of 6th class)
students identify the forms of energy produced in human body as chemical
energy (Table 5.9 (ii)). Maximum students of class 6th choose pressure as a
form of energy and students of 7th class choose friction and pressure both as
forms of energy. Students confuse between force, pressure and work.
177
About 63.3% of students of class 8th identify heat energy as the form of energy
produced in human body. This is 30% higher than the response of class 6th
and 20% higher than that of 7th class students. Still 21% of class 8th students
confuse force with energy and have the concept that force is the form of energy
produced in human body.
Upper primary students have not been formally introduced to forms of energy,
but 38% approx. of stage 2 and 63% of stage 3 understand the forms of energy
produced in human body. Learners typically start with the ideas of energy
related to personal experiences of human activities (Solomon, 1982).
About 21% of stage 3 students confused force with energy. Young students as
well as adults like the pre-service teachers have been known to have this
intuitive views about energy (Trumper, 1995) Trumper found that pre-service
teachers continued to confuse the concepts of energy and force even after
instruction for 4 years.
Historical evolution of energy reveals that the discoverers like Mayers, Joule
Colding and Helmholtz did not speak of energy but rather of force. The term
energy was introduced by William Thomson in 1851. Coelho (2009) suggests
that the historical approach to force and energy and the reflection on
experimental activities performed by scientists and their theories provide a
variety of examples which can be used by teachers to highlight science as a
human enterprise.
Table 5.9(iii): Students’ Conceptions about Energy in Living Systems
Stage 1
Concept
When you exercise well,
your energy levels_______
after exercise
Class IV & V
Age 9 to 10, N=401
Scientific Concept
Alternative Concepts
Become low 34.5%
Increases 47%
Do not Know 16.3%
178
To the questions whether our energy levels are increased or decreased after
exercise, 34.5% of stage 1 students think that energy will be depleted which is
scientifically acceptable (Table 5.9(iii)). A higher percentage of 47% think
energy is increased after exercise. They themselves feel tired after physical
work, but here they relate to building up of stamina (or strength over a period of
time) with the increasing energy level. A recent study by Mann and Treagust
(2010) with students of 8-12 years in Australia through an open-ended
questionnaire also have pointed out that there is limited understanding of
energy use, energy conversions and energy transfers in the body.
Understanding about role of respiration in conversion of food into useable
energy increases from age 8 to age 12 in a progressive way.
Judith Barak, Malka Gorodetsky and David Chipman (1997), of Israel in their
study on misconceptions regarding energy in biological systems and a
vitalistic notion of biology in 76 high school seniors (17years). They were
assessed with regard to: their conception of biological phenomena (scientific
vs. vitalistic), their understanding of the concept of energy in a biological
context, and the correlation between the two conceptions. The results pointed
to a strong correspondence between the ability to understand energy in
biological phenomena and adherence to scientifically oriented conception of
biology. They suggest that the conception of energy influences the conception
of biology, although an effect in the opposite direction cannot be ruled out.
The language we use in everyday context may be very different from the
context in which a term or concept has scientific meaning. Hence everyday
language becomes source of alternative concepts built by learners. ‘Building
up of energy’ is one such idiom used in common parlance which made 47% of
students of stage-1 have an idea that after exercise our energy levels
increase.
179
Table 5.10: Sun as the Ultimate Source of Energy
Stage 3
Class VIII
Age 13, N=196
Scientific Concept
Alternative Concepts
Solar energy stored in
wood grains & sugar is
called __________
Bio-mass 51.5%
Natural gas 30.1%
Fossil fuels 14.8%
Thermal energy 2%
The energy not derived
from sun is __________
Nuclear 21.4%
Wind energy 40.8%
Fossil fuels 19.4%
Bio-mass 15.8%
Concept
Class 8th students were asked to identify the type of energy stored in wood,
grain, sugar and municipal waste as energy from bio-mass (Table5.10). About
52% students understand energy from biomass and 30% do not know the
origin of natural gas, because they think that energy stored in wood etc is
natural gas.
The students of class 8th were asked to identify a source of energy which is not
derived from sun (Table 5.10). They were to identify among nuclear energy,
energy from bio-mass, wind energy and fossil fuels. The energy which is not
derived from the sun is not recognized by students of class 8th. Almost 41%
think wind energy is not derived from sun, but wind is always generated
because of sun. The correct answer is nuclear energy which was the second
choice of students.
5.5.2.2. Students’ Conceptions about Energy-Meaning, Forms of Energy,
Transformation of Energy
Four questions were asked to students of class stage1; 6 questions were put to
students of stage 2 and 7 questions were asked to students of stage 3. Fewer
questions were asked to younger students because of abstract nature of the
concepts; their conceptions about energy transformations were not tested.
Students of stage 2 and 3 were asked about meaning and transformation of
energy.
180
Table 5.11(i): Students’ Conceptions about Forms of Energy
Stage 1
Concept
Class IV & V
Age 9 to 10, N=401
Scientific Concept
Alternative Concepts
Electrical 42%
Force 22.4%
Pressure 19%
Friction 15%
__________is a form of
energy
Around 42% of stage1 students (31% of class 4th and 53% class 5th) identify
electricity as a form of energy. But the students are divided between equally
seemingly correct options like force, pressure and friction.
Table 5.11(ii): Students’ Conceptions about Forms of Energy
Stage 1
Concept
_________is the form of
energy used in batteries
of battery operated toys
Class IV & V
Age 9 to 10, N=401
Scientific Concept
Alternative Concepts
Chemical energy 35%
Renewable energy 24%
Solar energy 22%
Heat energy 17.5%
Only 33% to 37% students of class 4th and 5th identify the form of energy used
in battery operated toys as chemical energy. About 26% of class 4th and 22%
of class 5th think that the form of energy in an electric cell is heat energy.
Table 5.11(iii): Students’ Conceptions about Forms of Energy
Stage 1
Concept
Do moving
objects
have
energy?
Class
IV & V
Age 9 to 10,
N=401
Scientific
Concept
Alternative
Concepts
Yes 56%*
No 23%
Don’t know 17.8%
Stage 2
Concept
A moving
object has
_______
Class
VI & VII
Age 11 to 12,
N=360
Scientific
Concept
Alternative
Concept
Kinetic
energy
45.4%
Solar energy 26.4%
Renewable energy 19%
Light energy 4%
* Significant difference detected: Chi-square statistic=12.11, df =3, p<0.05.
181
Around 56% of stage-1 (51% students of class 4th and 62% of 5th) understand
that moving objects have energy (kinetic energy) (Table 5.11(iii)). A high
percentage 20-26% also thought that there is no energy in the moving objects.
Though students have not learnt about forms of energy, 45.4% of stage 2 (37%
of class 6th and 54% Class 7th) students identify kinetic energy as the form of
energy that all moving objects have. There is a jump of 17% in the response of
class 7th from class 6th. Dawson-Tunik (2004) followed Fischer’s categories of
cognitive levels in her sample of 171 class 9th students and identified 3 levels:
representational systems level, single abstractions level, abstract mappings
(AM). At the abstract mappings level, kinetic and potential energy are finally
understood as different energy states.
Kinetic energy is related to energy in moving objects and is easily observed
compared to potential energy. Historically too kinetic energy was discovered
earlier than potential energy. Students seem to understand kinetic & potential
energy in a similar sequence.
Table 5.11(iv): Students’ Conceptions about Forms of Energy
Stage 2
Concept
___________ energy of sun is
captured to prepare food for plants
Class VI & VII
Age 11 to 12, N=360
Scientific Concept
Alternative Concepts
Light energy 62%
Heat Energy 22.3%
Electrical energy 2.8%
All of these 10%
The form of energy of sunlight captured in photosynthesis-light or heat-were the
two main responses expected of students of class 6th and 7th (Table 5.11(iv)).
About 62% of stage 2 students respond correctly as light energy. The concept
of photosynthesis is taught in class 7th in detail, still more numbers of students
(24% of class 7th) are confused and select heat energy, 21% of students of
class 6th select heat energy. So a large number of students think that heat
energy of sun is utilised by plants during photosynthesis.
182
Hirca N., Calik M. and Akdeniz F. (2008) investigated 171 grade 8 students’ (from
9 schools of Turkey) understanding of ‘energy’ concept. About 60% percentage of
them is able to link type of energy plant absorbed with photosynthesis. Three fifths
of them could not apply their theoretical knowledge of types of energy to their
daily life experiences. The students thought that the plants obtained energy they
required to synthesis nutrition from salts and minerals (5%), carbon dioxide (8%),
and the mixture of water and carbon dioxide (22%). The plants convert sun light
energy into chemical energy (chemical bond energy) as nutrition. 38% of the
students failed to answer the related question. These results are in a harmony
with that of Anderson, Bach and Zetterqvist (1998).
Table 5.11(v): Students’ Conceptions about Forms of Energy
Stage 2
Concept
___________form
of energy change
water from liquid
to gas as it boils
Stage 3
Class VI & VII
Age 11 to 12, N=360
Class VIII
Age 13, N=196
Scientific
Concept
Alternative
Concepts
Scientific
Concept
Alternative
Concepts
Heat energy
87%
Mechanical 7.8%
Light 2%
Heat energy
99%
Mechanical-0.51
Light -0.23
120
100
80
99
80
84
Class 6th
Class 7th
60
40
20
0
Energy-Heat
Fig. 5.9: Forms of Energy
183
Class 8th
Majority (80-94%) of class 6th and 7th students identify the form of energy (i.e.
heat energy) which changes water from liquid to gas on boiling (Table 5.11(v)).
Students of class 8th easily identify heat energy as the form of energy in the
same question as 99% responded correctly (Figure 5.9).
Table 5.11(vi): Students’ Conceptions about Forms of Energy
Stage 3
Concept
___________energy is produced
when the bell rings
Class VIII
Age 13, N=196
Scientific Concept
Alternative Concepts
Sound energy 71%
Magnetic 18.4%
Electrical 9.7%
About 71% of students have the concept that the form of energy produced
while a bell rings is sound energy, but 18%think it is magnetic energy (Table
5.11(vi)). Students of class 8 th have exposure to the topic ‘Sound’ in class 8th.
Colin Boylan (2008) conducted a research on 132 elementary students (mainly
class 3rd to 6th) of Australia regarding their understanding of energy and
climate change concepts. Mostly elementary students identified all forms of
energy such as the light energy, kinetic energy, sound energy, thermal energy
& solar energy.
Table 5.11(vii): Students’ Conceptions about Forms of Energy
Stage 2
Concept
In__________example
energy is used the
most
Class-VI & VII
Age 11 to 12, N=360
Scientific Concept
Alternative Concepts
Heating a room by
room heater 64%
Filling water from tap 18.5%
Drinking a glass of water 16%
Watching a cricket match in the ground 10.7%
Maximum students of class 6th and 7th i.e 64% respond that room heater
consumes more energy compared to other situations like filling water in a
bucket or watching a match etc (Table 5.11(vii)). Around 18.5% students think
that filling water in a bucket from running tap consumes the most energy. These
184
students think of energy used by them for performing the tasks given. They
would use more energy for filling water than most other tasks.
Table 5.12: Students Conception about the Meaning of Energy
Stage 1
Concept
The best
definition of
energy is
__________
Stage 2
Class
IV & V
Age 9 to 10, N=401
Class
VI & VII
Age 11 to 12, N=360
Scientific
Concept
Alternative
Concepts
Scientific
Concept
Alternative
Concepts
The ability
to work
40%
The power of force 31.5%
Something you need to
live 24.4%
The ability
to work
39.5%
The power of force 41%
Something you need to
live 19%
A question was put to find what students of stage 1 and 2 would define energy
as (Table 5.12). They had to identify the definition of energy among other
options like the power of force or something you need to live etc.
Around 40% each from stage 1 and 2 identify definition of energy as ability to
work.
About 31.5% of stage 1 equates energy with force. Maximum students of stage
2 at 41% selected the power of force as definition of energy. This has been
earlier found by Watts and Gilbert (1986) that students use energy
synonymously with force or power.
About 24% of stage 1 and 19% of stage 2 students also think that energy is
something you need to live.
Many researchers (Viennot, 1979; Watts & Gilbert, 1983; Duit, 1984) have
noted that students fail to differentiate between energy and other physical
terms, mainly the concept of force.
As discussed earlier in this chapter, this reflects the confusion between energy
and force which scientists had during historical evolution of energy.
185
Table 5.13 (i): Students’ Conception about Transformation of Energy
Stage 2
Concept
__________energy in petrol
is transformed to movement
in a motorcycle engine
Class VI & VII
Age 11 to 12, N=360
Scientific Concept
Alternative Concepts
Chemical energy 48.8%
Sound 20%
Magnetic 14.5%
Electrical 15.5%
In response to a question pertaining to transformation of energy, maximum
students identified the form of energy in petrol as chemical energy which
changes to mechanical energy (Table 5.13(i)). About 49% of stage 2 (43% of
class 6th students and 55% of class 7th) students identified the transformation
scientifically. Rest of the students who were confused regarding transformation
of energy opted randomly.
Table 5.13(ii): Students’ Conception about Transformation of Energy
Stage 3
Concept
A solar cell converts
__________
Class-VIII
Age 13, N=196
Scientific Concept
Alternative Concepts
Solar energy to electrical 60%
Solar energy to light 19%
Heat energy to electrical 10.7%
Heat energy to lightening 9.7%
Almost 60% of students of class 8th correctly identify the transformation of
energy in a solar cell from solar energy into electrical energy (Table 5.13(ii)).
Table 5.13(iii): Students’ Conception about Transformation of Energy
Stage 2
Concept
Transformation
of energy in a
flashlight
(torch)
Stage 3
Class VI & VII
Age 11 to 12, N=360
Class VIII
Age 13, N=196
Scientific
Concept
Alternative
Concepts
Scientific
Concept
Alternative
Concepts
Chemical to
electrical and
to light 19%
Electrical to light to
heat 53%
Heat to light 22.4%
Chemical to
electrical and
to light 24.3%
Electrical to light to
heat 48.6%
Heat to light 25%
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Students of classes stage 2 and 3 were asked about energy transformations
taking place in a flash light and they do not know about the energy changes.
Maximum students opted for electrical to light to heat not knowing the chemical
energy in a battery. Class 8th students also could not identify the
transformation with certainty (Table 5.13(iii)).
Dawson-Tunik (2005) found that many ninth graders achieve neither an
understanding of energy as the ability to do work nor an understanding of
energy transfer.
5.5.3. Discussion
The following table gives the overall summary of the analysis from the primary
source.
Table 5.14: Scientific and Alternative Concepts across Stages
Stage 1
Source of Energy
Forms of Energy
Stage 2
Sources of Energy
Scientific Concept
Alternative Concepts
Coal is a fossil fuel
Wood is a fossil fuel
Wind is renewable energy source
CNG is a renewable energy
source
CNG causes less air pollution
Petrol cause less air pollution
Radiation from Sun gives heat in the
solar cooker
Food is source of energy
Mirror gives heat in a solar
cooker
Form of energy produced in the
human body is the pressure
Form of energy produced in the
human body is the Chemical
energy
When you exercise well your energy
levels become low after exercise
When you exercise well your
energy levels become increase
after exercise
Force is a form of energy
Electricity is a form of energy
Water is a source of energy in
man
chemical energy is the form of energy
used in battery of batteries operated
toys
Moving objects have energy
Renewable energy is the form of
energy used in the battery
operated toys
Best definition of energy is ability to
work
Scientific Concept
Best definition is the power of
force
Alternative Concepts
A source of energy heats both solar
cooker and gas stove
Gas heats both solar cooker
and gas stoves
Food is source of energy
Water is a source of energy in
man
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Moving objects do not have
energy
Form of energy produced in the
human body is the Heat energy
Form of energy produced in the
human body is the force
Moving objects have kinetic energy
Moving object have solar energy
light energy of sun is captured to
prepare food for plants
Heat energy of sun is captured
to prepare food for plants
Heat energy changes water from lipid
to gas as it boils
Forms of Energy
Stage 3
Source of Energy
In heating a room by room heater
energy is used the most
In filling water from tap energy
used the most
Best definition of energy is ability to
work
Best definition is the power of
force.
Chemical energy in petrol is
transformed into movement in a
motorcycle
Sound energy in petrol is
transformed into movement in a
motorcycle
Transformation of flash light is
chemical to electrical and to light
Electrical to light and to heat
Scientific Concept
Alternative Concepts
Substances producing a lot of heat
on burning is called fuel
Substances producing a lot of
heat on burning is called biogas
Decomposition reaction transform
organic material to petroleum
Elevated temperature
transforms organic material to
petroleum
CO2 Emission, ash and acid rain are
problems associated with burning of
coal
CO2 emission is the problem
associated with burning of coal
Natural gas produces least CO2 per
unit of energy
Coal, Oil and natural gas
produce the same amount of
carbon dioxide.
Uranium does not produce carbon
dioxide
Natural gas does not produce
CO2
Form of energy produced in Human
body is heat energy
Form of energy produced in
Human body is force
Solar energy stored in wood and
grains are known as biomass
Solar energy stored in wood and
grains are known as natural gas
Energy not derived from sun is
nuclear energy
Energy not derived from sun is
wind energy
Heat energy changes water from
liquid to gas as it boils
Forms of Energy
Should energy is produced when the
bell rings
magnetic energy is produced
when the bell rings
A solar cell converts solar energy to
electrical
A solar cell converts solar energy
to light
Transformation of energy in a flash
light is chemical to electrical to light
Transformation of energy in a
flash electrical to light to heat
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From the primary data, one may generalise that students of higher class i e
older students understand concepts of energy better than junior students, but
students’ understanding of energy concepts did not improve in class 8th despite
their exposure to energy-related concepts like heat and temperature,
combustion, electricity, fuels etc. Students may require direct instruction in the
topic energy rather than covertly placed energy topics.
Understanding about energy concepts can be generalised only about the items
asked. Different patterns may emerge if other sub-concepts of energy are
included in the items. The generalisations about findings in this study are
limited, since sample came from five schools that served diverse school
populations in terms of language, socio-economic status and achievement.
Tracing the trajectory of evolution of science concepts among elementary
students is challenging. Fundamental ideas tend to be abstract and
parsimonious, their appropriateness and usefulness cannot be appreciated by
students without the conceptual resources or epistemological commitment of
the practising scientific community. Owing to developmental and experiential
constraints of students, some of the energy concepts may be difficult for
students to understand.Evolution of energy concepts among elementary
students does not happen linearly. Students are found to progress towards
more scientific understanding. The concepts found difficult by primary students
were found easy by middle level students. By the time students complete
elementary stage, they conceptualise most concepts except the concepts
related to transformation of energy easily. Students conceptualise the concepts
related to their social context easily while find the scientific concepts difficult.
They find phenomenal concepts easy to understand than concepts which need
conceptual explanations. Items requiring elicitation of single ideas is found easy
by the elementary students and items requiring connections among multiple
ideas is found difficult .
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5.6. Conclusion
Students have similar confusion regarding energy concepts as was held by
scientists in history. Students equate energy with force. Kinetic energy is
understood easily by students compared to potential energy. Various forms of
energy were understood earlier by the scientific community compared to the
transformation or conservation of energy. Elementary students seem to have
similar understanding about energy concepts.
The various alternative concepts found in elementary students are similar to
those held by elementary students as reported widely by researchers. However
interviews about tasks/activities elicit different responses which are categorized
later into variety of ideas held about nature of energy. The fixed response
questions elicit different responses. Even then, many of the alternative
conceptions in energy hold true across countries and even age.
Due to abstract nature of the energy, the questionnaires developed to probe
into students understanding of related concepts could focus on limited but
important concepts in each topic. However, analysis of elementary students’
understanding opened a window into the world of their understanding of these
concepts. Their responses show that
though progression of many important
concepts occur across elementary classes, many important concepts intended
at a class
are not grasped by them and they have certain alternate
conceptions.
The
recommendations
in
terms
of
improved
deliberate
pedagogical interventions to support conceptual understanding of students
have been made by researchers. However, the curriculum developers as well
as textbook authors need to take these into account while organising and
sequencing curriculum across elementary classes
The purpose of this part of the study has been to trace the evolution of
concepts of energy by elementary students. The analysis of responses in this
part may not provide an exhaustive understanding but provides a cue for
placement of concepts to attain progression.
190