BSCS Science Tracks:
Connecting Science & Literacy
Second edition, © 2006 by BSCS
Investigating Plants
Unit Overview
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Module Overview
Introduction to Investigating
Plants
Plants are a part of children’s everyday lives.
They eat fruit and vegetables, write on paper,
and wear clothes that are made from plants.
Sometimes we tend to take plants for granted
and forget that, as the basis of the food chain,
plants are of primary importance to all life on
Earth. A major goal of this module for students
is to develop an awareness that plants are
living organisms that have specific biological
requirements that must be met if plants are
to grow and survive. Another goal for students
is to develop an understanding that plant
structures have specific functions that help the
plant survive.
What do children of this age believe about
plants? Researchers have investigated students’
thinking regarding plants. The results are
enlightening and should encourage you to ask
questions of your students throughout this
module.
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Module Overview
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The Concept of Plant
Stead (Bell) established, from interviews
with twenty-nine children aged 9–15, that
they had a much narrower meaning of the
word “plant” than that of the biologist. Only
four children used generalized criteria such
as “grows in the ground,” “has leaves,”
“has roots,” “is green,” to categorize all the
instances of plants. Bell found children, from
all age groups, who considered that a tree
is not a plant, although they said “it was a
plant when it was little.” Over half did not
consider a seed to be a plant. It appears
that many pupils view weeds, vegetables
and seeds not as sub-sets of the set “plants”
but as comparable sets.—Driver, Squires,
Rushworth, & Wood-Robinson, 1994, p. 23
Before teaching the lessons in this module,
you might want to find out what the students
in your classroom believe about plants. Do
they understand that trees, vegetables, seeds,
and weeds are all plants? Knowing what the
students believe before beginning the module
will help you select questioning strategies and
an approach to activities that will confront
students’ current ideas that are not consistent
with the scientific concept of plants.
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Photosynthesis
The following discussion of photosynthesis
illustrates why we have not included the
concept in this module.
Arnold and Simpson sum up the demands
made by the abstract and complex concept of
photosynthesis by pointing out that pupils need
to understand that
an element, carbon (which is solid in pure
form), is present in carbon dioxide (which is
a colorless gas in the air) and that this gas
is converted by a green plant into sugar (a
solid, but in solution) when hydrogen (a gas)
from water (a liquid) is added using light
energy which is consequently converted to
chemical energy.
They suggest that many pupils do not
possess the prerequisite concepts of living
things, gas, food, and energy, which are
required to build an understanding of
photosynthesis.
Barker and Carr comment “how unlikely
and counterintuitive is the concept of
photosynthesis.” The sequence of events has
the “makings of a fairy story. How much more
plausible is the probability that plants suck up
food from the soil” (Driver, Squires, Rushworth,
& Wood-Robinson, 1994, p. 30).
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The concept is quite abstract and requires
a knowledge of other abstract concepts that
are beyond the scope of this module. We feel
that an understanding that plants have certain
biological requirements is a precursor to
understanding the concept of photosynthesis.
Students will encounter the concept of
photosynthesis in middle school or high school
when it will make more sense to them.
Plant Nutrition and Growth
The concept of food for plants is also a difficult
one for students of this age because it is related
to the concept of photosynthesis:
Children, understanding that plants absorb
water from the soil and that water is
essential to growth, appear to assume that
it is the main component of growth material.
Having learnt that plants take in carbon
dioxide, water and minerals, pupils tend
to regard these as the food of plants and
when food is associated with energy, these
inorganic substances are assumed to contain
and supply energy.
—Driver, Squires, Rushworth, &
Wood-Robinson, 1994, pp. 31–32
In this module, we do not emphasize the
concept of plants’ “food” or energy source;
however, we do indicate that the minerals and
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water that plants absorb through their roots are
not food for the plant. Do not expect students to
understand this completely as a result of their
experiences in this module. The idea that plants
use water and carbon dioxide from the air in
the presence of light to make their own energy
source, or food, is difficult to understand,
even for older students. Simply reinforcing the
concept that plants produce their own food,
or source of energy, and do not take food in
from the environment as animals do, will help
prepare them for later study of the concept.
As students participate in and discuss the
activities in this module, they begin to recognize
the following concepts:
•
Plants are living things that have basic needs
for air, light, and water.
•
Plants must be able to obtain their needs
from the environment in order to survive.
•
Plants have structures that serve specific
functions in obtaining air, light, and water
from the environment.
•
Plants can only live in environments in which
they are able to obtain their basic needs.
In this module, students investigate plants’
requirements for air, light, and water. Because
of the students’ developmental level, we use
the term “needs” in the student guide when
referring to the things that plants require for
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growth and survival. Because many people often
connect the term needs to a conscious desire
for something, scientists do not use that term
when referring to the biological requirements
of plants. Plants do not consciously desire
anything, but they will not survive if they do not
obtain certain things, specifically air, water, and
light from the environment.
To make the concept of biological
requirements accessible to young students,
we chose to use the common term needs instead
of the scientific term. The students have a frame
of reference, based on their own experiences, for
understanding the term needs; however, to avoid
misconceptions, it is important that you help
students understand the difference between a
plant “needing” (requiring) something to survive
and grow versus “wanting” something.
Students develop their understanding of the
above concepts by doing these things:
1.
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Students confront their currently held beliefs
as they explore the following questions:
•
What do seeds need to produce plants?
•
What is inside of a seed that produces new
plants?
•
What do plants need to survive and grow?
•
What evidence do we have that plants need
air, light, and water?
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2.
•
What structures enable plants to obtain
their basic needs?
•
How do plants survive in the environment?
Students investigate to find out if plants
need air, light, and water by engaging in the
following stages of scientific inquiry:
•
Setting up and conducting simple
investigations to gather evidence
•
Observing by using their senses and
simple tools such as hand lenses
•
Recording their observations
•
Communicating the results of their
investigations and sharing evidence
•
Answering questions and using evidence to
support their answers
3.
Students compare their firsthand
observations with what scientists know about
plant structures and how they enable plants
to obtain their basic needs.
4.
Students observe plants outdoors and
discuss how structures enable plants to meet
their needs in different environments.
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In addition to enabling students to construct
their understanding of plants’ needs and
structures, the lessons in this module provide
students with
•
hands-on, minds-on learning experiences;
•
critical-thinking and inquiry skills;
•
conceptually developmental and sequenced
experiences;
•
literacy strategies in reading, writing,
listening, and speaking;
•
opportunities to learn collaboratively with
other students; and
•
integrated activities that encourage
curiosity and imagination.
See “Module at a Glance” for a summary of
the lessons and the development of the concept
of investigating plants.
Connecting Science and Literacy
Time is a precious commodity in the elementary
classroom. To reach standards in all content
areas requires that we think differently about
instruction. Of course, learning to read during
these early years is vital. Did you know that
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science and reading share many process
skills? Think about it. Can you read effectively
without activating prior knowledge, predicting,
making inferences, and drawing conclusions? In
addition, science offers a platform for authentic
reading and writing. It provides students with a
purpose for reading and writing.
Literacy strategies are embedded in lessons
of this module; however, there are some
general things that you can do to support the
science and literacy connection. Please note
the following information regarding scientific
vocabulary, reading comprehension, text
structures and supports, and the science
notebook or folder.
Scientific Vocabulary
While we have tried to be considerate
about reading level, scientific vocabulary
raises reading levels. Students need many
opportunities to develop science vocabulary.
Words need to be introduced and discussed
during activities. Students need to read and
write these words frequently during the module.
We encourage you to incorporate your own
vocabulary strategies as well as the strategies
recommended below and throughout the module.
Keep in mind that the vocabulary strategies
should foster and support reading in science.
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Vocabulary strategies that you choose to use
should
•
help students make connections among
words,
•
link new words to other words they already
know in science,
•
involve the students in constructing the
meaning of the word, or
•
clarify the meaning of the word.
Interactive Word Wall
One way to ensure students use science words
is through the use of an interactive word
wall. A word wall is an organized collection of
words displayed in large letters on a wall or
other space in the classroom. Word walls have
been extensively used for spelling and reading
vocabulary. But word walls can also provide a
place for students to review and learn important
content words. Though there are no set rules for
word walls, we recommend that the words be
written on large index cards, strips of paper, or
tagboard so that they can be used for activities
throughout the module. We also recommend
that not many words be put up on the wall
at one time. Recommended words are listed
for each lesson. During science, the teacher
can use the word wall to review and make
connections for younger students.
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Word Wall Objects
If at all possible, place a photograph or a
clear plastic bag with the object inside next to
the words on the word wall. This allows your
students, particularly your English Language
Learners, another connection to the word.
Covered Word Sentences
Reinforce the use of the word wall words by
using the word wall words in a sentence.
1.
Write a few sentences incorporating words
from the word wall. This can be done on
the board, sentence strips, or the overhead
projector.
2.
Cover the word wall word with a sticky note
or paper.
3.
Ask a student to read the sentence aloud as
written.
4.
Encourage the student to guess which word
wall word “fits” best in the sentence using the
contextual clues.
5.
Uncover the word wall word when a correct
guess is made.
6.
Instruct all students to read the sentence
aloud together.
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Word Sorts
Word Sorts (Gillett & Temple, 1983) help
students build conceptual understanding
through sorting and classifying. Terms are
written on cards (one term per card), and
students are asked to group the terms into
categories. Teacher-generated categories are
referred to as a closed sort. Student-generated
categories are referred to as an open sort.
As words are added to the word wall, ask
students to sort them by category. As students
expand their descriptive vocabularies, classify
their words on the word wall. It is also helpful
to add visual representations (e.g., pictures,
actual objects with textures) of words to the
cards to help students make connections.
Student Glossary
Encourage students to create their own glossary
in their science notebooks or folders. One
strategy is to instruct them to make a 3-column
entry page. In the first column, they write the
term. In the second column, students draw a
picture. In the third column, students write a
definition or give examples.
Another activity that is helpful to English
Language Learners is the use of word cards.
Students use index cards to write each word.
They then draw a picture of the word. These
words are kept together on a ring or in an
envelope to use as a reference. The use of
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individual word cards allows the students
personal access to the science words.
Reading Comprehension
The read-aloud/think-aloud strategy (Davey,
1983) is a powerful strategy for developing
effective readers. It provides students with the
opportunity to explicitly “see” processes that
should be occurring behind their eyes as they
read. The teacher models his or her thinking
process by verbalizing thoughts as he or she
reads. Students read along as the teacher
interacts with the text. As you read aloud/
think aloud with your students throughout
this module, look for opportunities to model
strategies that do the following:
•
Activate prior knowledge (e.g., “According to
the title, this passage must be about . . .”)
•
Create visual images (e.g., “As I read this, I
get a picture in my mind that . . .”)
•
Look for connections (e.g., “This is like the
activity . . .”)
•
Make and adjust predictions (e.g., “I thought
that this was going to happen, but really . . .”)
•
Ask questions (e.g., “I wonder what the
author meant by . . .”)
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•
Infer what is meant (e.g., “I think that
means . . .”)
•
Adjust the pace of reading (e.g., “This looks
pretty tricky, I’d better slow down . . .”)
•
Monitor understanding of what is being read
(e.g., “I didn’t get that, I’d better reread . . .”)
•
Determine the most important ideas
(e.g., “I want to remember . . .”)
•
Summarize (e.g., “This is what I
understand . . .”)
Text Structures and Supports
Text structures and supports are features used
to cue the reader. They include things like titles,
subtitles, photographs, illustrations, graphs,
boldfaced type, icons, hints in the margins, the
table of contents, and the glossary. As you begin
to use the student guide, introduce students
to its structures and supports. As you work
through the module, remind students that text
structures and supports are designed to help
them learn.
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Science Notebook or Folder
Throughout this module, students are asked
to use a science notebook or folder. This is a
place for students to collect their observations,
ideas, sketches, and record pages. It can be as
simple as record pages and blank pages stapled
together. Choose a format that works for you.
The important thing is that students have a
place for experience, data, and language to
come together to form meaning.
Conceptual Outcomes
Students’ experiences throughout this module
help them develop an understanding that plants
require air, light, and water to survive and that
certain structures enable plants to meet these
needs.
The following table illustrates the priority
placed on conceptual development in the
module and also displays the correlation of the
module’s conceptual outcomes with the content
standards in the National Science Education
Standards and the Benchmarks for Science
Literacy.
Module Overview 35