USE OF THE LAVAâ LAMP AS AN ANALOGY IN THE GEOSCIENCE
CLASSROOM
Stephen G. Tolley
Florida Gulf Coast University, College of Arts and Sciences, 10501 FGCU Boulevard
South, Fort Myers, Florida 33965-6565, [email protected]
Sherry D. Richmond
University of Florida, P.O. Box 110410, Gainesville, Florida 32611-0410, [email protected]
ABSTRACT
We have developed an exercise for the geoscience
classroom that uses the LAVA lamp as an analogy to
introduce general education undergraduate students to
oceanography. The exercise provides a link between
previously learned (from their secondary educational
experience) and new knowledge by placing basic
principles of science within an oceanographic context.
Previously learned concepts that are built upon in the
exercise address the properties of matter, the
transformation of energy, force and motion, and the
global processes that shape the Earth. The exercise
requires students to compile an extensive list of
observations using the lava lamp, to derive meaning
from these observations and share this meaning with
their peers, and to apply this meaning to new course
content. Some of the more common observations
recorded by students deal with changes of state in
matter, differences in density among the lamp’s
components, the influence of temperature on density and
thus on buoyancy, the formation of convection cells, and
thermal expansion of fluid volume. We have found the
exercise to be a useful way of introducing lower-division
students to such related processes as adiabatic
atmospheric circulation, global warming and sea level
rise, and most especially magma movement contributing
to global plate tectonics.
Keywords: Education geoscience; education
precollege; educationscience; education
undergraduate; geoscience teaching and
curriculum; marine geology and oceanography;
plate tectonics.
LAVA®, LAVA LITE®, LAVA WORLD INTERNATIONAL® and the configuration of the LAVA®
brand motion lamp are registered trademarks of
Haggerty Enterprises, Inc. The configuration of the globe
and base of the motion lamp are registered trademarks
of Haggerty Enterprises, Inc. in the U.S.A. and in other
countries around the world. ©2002 Haggerty
Enterprises, Inc. All rights reserved.
“There is no better, there is no more open door by
which you can enter into the study of natural
philosophy than by considering the physical
phenomena of a candle. There is not a law under
which any part of this universe is governed which
does not come into play, and is not touched upon,
in these phenomena.” Michael Faraday, “The
Chemical History of a Candle,” p. 1
Tolley and Richmond - Use of the Lava Lamp
INTRODUCTION
The burning candle has served not only as a metaphor for
science itself (Sagan, 1995; Ho, 1997; Laidler, 1998), but
ever since Michael Faraday’s classic discourse (Faraday,
1861), it has also been the subject of examination within
the science classroom. Candles were originally burned as
a part of the curriculum either to illustrate the inherent
complexities of seemingly simple phenomena or to
demonstrate the basic principles of combustion (the
appropriateness of some of these usages has since been
questioned, see Birk and Lawson, 1999). More recently,
candles have been used to examine convection
(Buchman, 1992), rotation (Mou, 1997) and even
microgravity (Ross, 1998, Candle drop, 1999). We have
been using the Lava lamp in the geoscience classroom as
a contemporary corollary of the burning candle. Like the
candle, the lava lamp provides an opportunity for
students to compile an extensive list of observations
from which they can later infer meaning.
The lamp consists of three primary components,
each of differing density and each of differing degree of
thermal expansion (Figure 1). The first component, a
transparent liquid consisting of dyed water (U. S. Patent
Office, 1968), is of lesser density than the second–
popularly referred to as the lava. The lava itself is
described as being comprised of mineral oil and paraffin,
with a melting point that allows it to change state from a
solid to a liquid at temperatures of 40-50º C (U. S. Patent
Office, 1968). Located above these two substances is an
air space that can expand or contract in response to the
thermal expansion of the more dense liquid and lava. All
three of these components are sealed within a glass
vessel that sits upon a base. A 40-watt appliance bulb
housed in the lamp’s base serves as the energy (heat)
source.
In a cold lamp (turned off), the lava is in its solid state
lying at the bottom of the vessel, the air space at the top of
the vessel is at its largest volume, and no movement can
be detected in any of the lamp’s major components. After
the heat source is turned on and the lamp begins to
warm, the solid lava slowly begins to melt, becoming a
viscous liquid and maintaining its opacity. As its density
is reduced by thermal expansion, the lava begins to rise
though the transparent liquid. This rising lava begins to
break off from that still at the bottom of the vessel and
forms odd shapes. As the lava continues to rise toward
the surface of the vessel and away from its heat source, it
begins to cool and then sinks, eventually amalgamating
with the lava remaining at the bottom of the vessel. This
cycle of thermal convection may take from tens of
minutes to several hours to fully develop, during which
time the air space in the top of the vessel continues to
contract in volume.
217
USE IN THE CLASSROOM
The lava lamp exercise was developed for an
undergraduate general education course to reacquaint
students with some basic principles of science so that
they might then apply these principles to understand
particular oceanographic processes. The lava lamp could
also prove useful in introductory geology courses, where
a variety of analogies have already been developed in
order to teach more effectively principles related to plate
tectonics (for a complete listing see Nottis, 1999). Here it
could be used not only to introduce such concepts as
mantle plume movement and the formation of intrusive
igneous bodies, but also to present salt diapir formation
and adiabatic processes in the atmosphere.
At Florida Gulf Coast University (FGCU), only 10%
of the incoming freshmen are from out of state.
Therefore, the vast majority of our first-year students
have been exposed to Florida’s Sunshine State
Standards, a series of learning goals adopted by the State
that define expectations of student performance
according to both grade level and subject matter
(Sunshine State Standards, 2000). These standards also
provide a baseline of prior knowledge that
post-secondary instructors can use to build upon.
Standards relevant to the lava lamp exercise address the
following: properties of matter including changes of
state; the transformation of energy; the relationship
between forces acting on an object and the object’s
motion; and “processes in the lithosphere, atmosphere,
hydrosphere, and biosphere” that “interact to shape the
Earth” (Sunshine State Standards, 2000).
Because the lava lamp is immediately recognizable
to most students, it engenders a sense a familiarity even
before the exercise begins. The exercise is used during
the first class meeting and provides students with an
opportunity to complete a number of cognitive tasks that
fall into several previously recognized categories of
learning (Bloom and others, 1956; Marzano, 2001). It also
exposes them to a pluralism of ideas through interaction
with their peers. As a consequence, we find the exercise
to be a valuable, disarming tool that can be used to
immediately move students beyond the simplistic
authority-oriented view of knowledge that they may still
be clinging to at the beginning of their college experience
(Perry, 1970) and on to higher levels of cognitive
complexity (Lynch and others, 2001).
Learning goals are explicit: (1) to help students see
the value of making simple, but careful, observations; (2)
to reacquaint students with basic principles of science;
(3) to introduce students to new course content by
relating it to these basic principles; and (4) to stimulate
higher order thinking by asking students to function at
several levels of intellectual competency.
The exercise can be broken down into three parts:
individual observation, written questions and student
responses coupled with small-group discussion, and
large-group discussion facilitated by the instructor that
challenges students to apply what they have learned to
new course content.
Observation - At the beginning of the exercise, students
are asked to spend a few minutes individually
examining a lava lamp in its cold state and to record
these initial observations for use later in the class.
Students are restricted in their interaction with the lamp:
they may touch the lamp, but may not disturb it in any
way. This prevents the lamp’s components from
218
Figure 1. Simplified illustration of a LAVAâ lamp.
Primary components include a transparent liquid, a
wax-like substancethe lava, and air, all sealed within
a glass vessel. Housed in the base of the lamp, below
the vessel, is a light bulb with reflector that serves as
the energy source driving the motion of the lamp.
becoming partially emulsified due to excessive moving
or shaking. Furthermore, students are not provided with
any information concerning the lamp’s structure or
function.
As students redirect their attention toward other
tasks unrelated to the exercise, several lamps are allowed
to warm up. Since the class meets for 2 hours and 15
minutes, this warm-up time allows the instructor to
cover other materials related to the class’ first meeting.
This shift in focus is facilitated by a combined
lecture-laboratory approach to science teaching at
FGCU. Science classrooms are designed to be able to
move students easily back and forth between laboratoryand lecture-based modes of instruction within the same
space. Science courses are then scheduled with lecture
and laboratory sections combined. This classroom
design allows for flexible teaching and limits the number
of students to approximately 30.
After a sufficient warm-up period, students
assemble into small groups and begin making additional
observations of a lamp that is now fully cycling. Typical
observations made include the illumination and
warming of the lamp itself, the melting of the lava from a
solid to a liquid form, the rising and falling of liquid lava,
the nature of the shapes that are formed as the lava rises
and separates from that remaining at the bottom of the
lamp, the apparent immiscibility of the lava and liquid
Journal of Geoscience Education, v. 51, n. 2, March, 2003, p. 217-220
components, and the volumetric changes that have concepts regarding the interaction of matter and energy
occurred in both the liquid and the airspace since the they infer that thermal expansion has taken place;
applying this principle to oceanography, students
initial observations of a cold lamp.
suggest that increasing heat input into the global ocean
Written Questions and Student Responses - As will result in sea-level rise; finally, students predict a rise
students assemble into their small groups to examine in sea level as one of the potential outcomes of global
their lava lamp, they are provided a handout with a set of warming. In a similar fashion, change of state, the effect
questions (Table 1) that asks them to record carefully of temperature on density, the relationship between
their observations, to explain the underlying processes density and buoyancy, and thermal convection can all be
that they think are at work, and to break down these combined to introduce adiabatic processes in both the
processes into their component parts in order to explore mantle and the atmosphere that drive large-scale
the relationships among them. These questions are circulation and that transport heat. The effect of
meant to stimulate student responses that demonstrate temperature on density can also be used to illustrate the
different levels of competency relevant to the concepts formation of deep water at high latitudes. A more
being explored, specifically knowledge, comprehension, complete listing of examples in which the lamp has been
application, and analysis as described by Bloom and used as an analogy to place basic scientific principles
others (1956). After responding to these questions, within an oceanographic context is presented in Table 2.
students are encouraged to discuss what they see with
other members of their group and to observe the other CONCLUSION
lava lamps that are set up in the classroom. It is at this
stage of the exercise that students begin to connect their Recent research suggests that a portion of the Earth’s
observations with previously learned scientific concepts: interior, the deep mantle, behaves as a sort of lava lamp
melting lava is framed within the context of changes of set on low (Kellogg and others, 1999; Kerr, 1999). It seems
state; the rising and sinking of lava is expressed in terms appropriate then that the lava lamp exercise be used in
of the effects of heating and cooling on density and of the the oceanography classroom, for it is this very process of
formation of convection cells; and changes in the volume global plate tectonics that is responsible for the continual
of the liquid and of the air space at the top of the lamp are creation and renewal of the ocean basins themselves. The
viewed in light of thermal expansion. By using the lava lava lamp provides a striking reference point at the
lamp to reacquaint students with these basic principles beginning of the course that can be used later on by the
of science, we set the stage for introducing new material instructor to stimulate student thinking about a variety
related to oceanography in a manner that is both of concepts that are integral to the study of
reinforcing and disarming.
oceanography. As such it can be referred to whenever
one or more of these concepts need to be applied to
Large-group Discussion - After the students have had understand new course content. As unveiled in class
time to respond in writing to the above questions and to discussions, students also find the exercise useful and
discuss these responses with other members of their continue to refer back to it as an analogy for
small group, the class is reconvened as a whole in order understanding oceanographic principles. Furthermore,
to share and compare work. It is during this stage of the students’ references to the exercise on exams given
exercise that students begin to develop a common weeks later suggest that the lava lamp has proven
vocabulary and to apply the principles under discussion helpful to them in the learning process. Just as the
to course content. Specifically, the last question on the burning candle has served as science’s symbol, so too the
student
handout“What
processes
related
to lava lamp can be a useful metaphor, especially in the
oceanography do you think might be explained using geosciences.
some of these same principles?”is used as a lead-in to
begin introducing students to oceanographic principles ACKNOWLEDGMENTS
and phenomena. This transition to course content is
facilitated by the instructor and begins with a modified We thank José Barreto, Win Everham, Jerry Jackson,
brainstorming session in which students offer concepts Rebecca Totaro, and Aswani Volety for their comments
assembled from an examination of the lava lamp that on and careful reviews of early drafts of the manuscript
might be applied toward oceanography. A large list of as well as Joseph Tolley for his illustration of the lamp.
ideas is developed and is then sorted and grouped by the We also thank Journal of Geoscience Education
instructor based upon some of the major oceanographic reviewers Marek Cichanski, Ralph Dawes, Robert
themes that are to be introduced as part of the course.
Hooper, and Jeffrey Noblett for their valuable
The lava lamp is a useful analogy that helps students suggestions on how to strengthen the work. The senior
relate previously learned concepts such as changes of author expresses his gratitude to Michael McDonald for
state, the effect of temperature on density, the influence lengthy discussions regarding both learning outcomes
of density on buoyancy, thermal convection, and thermal and lava lamps. This represents contribution 14 from the
expansion, to oceanography. For example, students Whitaker Center for Science, Mathematics, and
observe that as the lava lamp heats up, the volume of the Technology Education at Florida Gulf Coast University.
fluid in the lamp increases; recalling previously learned
Tolley and Richmond - Use of the Lava Lamp
219
REFERENCES
Birk, J. P., and Lawson, A. E., 1999, The persistence of the
candle-and-cylinder misconception, Journal of
Chemical Education, v. 76, p.914-916.
Bloom, B., M. Englehart, E. Furst, W. Hill, and D.
Krathwohl, eds., 1956, Taxonomy of Educational
Objectives: The Classification of Educational Goals,
by a Committee of College and University
Examiners, Handbook I, Cognitive Domain, David
McKay Co., New York.
Buchman, J., 1992, Candle convection, Science Scope, v.
16, p.44-45.
Candle drop, 1999, Space Team Online, Retrieved July
12, 2002 from the World Wide Web,
http://quest.arc.nasa.gov/space/teachers/microgr
avity/9flame.html.
Faraday, M., 1861, The Chemical History of a Candle
(1993 reprint edition), Atlanta, Georgia, Cherokee
Publishing Company, 192 p.
Ho, D. D., 1997, Science as a candle of hope: we can
change the world, Vital Speeches of the Day, v. 63,
p.660-662.
Kellogg, L. H., Hager, B. H., and van der Hilst, R. D.,
1999, Compositional stratification in the deep
mantle, Science, v. 283, p.1881-1884.
Kerr, R. A., 1999, A lava lamp model for the deep Earth,
Science, v. 283, p. 1826-1827.
Laidler, K. J., 1998, To Light Such a Candle: Chapters in
the History of Science and Technology, New York,
New York, Oxford University Press, 400 p.
220
Lynch, C. L., S. K. Wolcott, and G. E. Huber, 2001, Steps
for better thinking skill patterns [On-line], Retrieved
July 12, 2002 from the World Wide Web,
http://WolcottLynch.com.
Marzano, R. J., 2001, Designing a New Taxonomy of
Educational Objectives, Thousand Oaks, California,
Corwin Press, Inc., 149 p.
Mou, Q., 1997, A candle in a rotating coordinate system,
The Physics Teacher, v. 35, p. 542-543.
Nottis, K.E.K., 1999, Using analogies to teach
plate-tectonics concepts, Journal of Geoscience
Education, v. 47, p. 449-454.
Perry, W. G., Jr., 1970, Forms of Intellectual and Ethical
Development in the College Years: A Scheme, Holt,
Rinehart, and Winston, Inc. New York, 256 p.
Ross, H.D., 1998, Fires in free fall, Scientific American, v.
278, p. 49.
Sagan, C., 1995, The Demon-haunted World: Science as a
Candle in the Dark, New York, New York, Random
House, 457 p.
Sunshine State Standards, 2000, Florida Department of
Education: Retrieved July 12, 2002 from the World
Wide Web, http://www.firn.edu/doe/curric/
prek12/frame2.htm.
U. S. Patent 3,387,396, 1968, Display devices, United
States Patent and Trademark Office, Washington, D.
C., 3 p.
Journal of Geoscience Education, v. 51, n. 2, March, 2003, p. 217-220