You be Forcin’ It
Keith Zeise and Michael Lawton
Abstract:
This is an inquiry-driven lesson with many layers that is structured utilizing the 7 E’s learning cycle approach (elicit,
engage, explore, explain, elaborate, evaluate, extend). The concept taught is inter- and intra-molecular forces. The
lesson consists of several demonstrations and quantitative experiments where students create their own model about
inter- and intra-molecular forces, are formally introduced to the concept, and then apply the model to several new
situations.
About the 7 E’s
The 7 E model is a constructivist, inquiry-driven, learning-cycle type approach to teaching. It uses the following steps.
1. Elicit. Probe the students’ preconceptions about a topic. This can serve as a cognitive anchor with which they
can build upon.
2. Engage. Prick the students’ interest in the topic. This can be a discussion, video, or demonstration that
generates curiosity or concern with the topic. Discrepant events work well here.
3. Explore. The students develop their own cognitive models about the topic. They can do their own research or
experiments.
4. Explain. The teacher presents the concept or model that the students will be working with.
5. Elaborate. The students use the concept or model in a new situation or situations. They articulate how the
model applies.
6. Evaluate. The students analyze the effectiveness of the model in new situations, and critique their own and/or
each others’ processes.
7. Extend. The students apply their learning and make it relevant in real life situations, or interdisciplinary
applications.
7 E’s Lesson Plan
Elicit
Present the students with this question and discuss the justifications for their answers.
When water evaporates by boiling, circle all of the following things that occur.
a. Water splits into hydrogen and oxygen
b. Water molecules increase their distance from each other
c. Air bubbles are produced
d. Water chemically reacts with air to produce bubbles
e. Bubbles contain oxygen and hydrogen gas
Engage
Engage the students with any or all of the following discrepant events.
 Pepper afraid of soap demo: sprinkle pepper on a wide surface of water; add one drop of dish soap and the
pepper sprinkles “shoot” to the sides of the water.
 Floating pins or paperclips: gently rest a few paperclips or pins on the surface of clean water (the more pure
the water, the easier it is) and they will float! Using a plastic fork to “rest” them on the surface of the water
can help.
 Lycopodium powder or magic sand: Fill a 250mL beaker 2/3 full with water. Lycopodium powder will float
on the surface and you can “dip” your finger in it and your finger will come out dry. “Magic sand” can be
ordered from science catalogues, it is a sand that when added to water, will come out dry because it has a
nonpolar substance coating it.
Explore
Students will carry out a quantitative experiment measuring
the viscosity of several pure liquids.
Chemicals needed: Hexane, propanol, propylene glycol, and
glycerol. This list is by no means definitive. These chemicals
were chosen for their differences in the number of OH groups.
Other chemicals may be chosen based on preference and/or
availability.
Materials needed: 10mL pipettes (4 per lab group
recommended; any kind of small-diameter passageway will
suffice, such as a burette, glass tubing, or test tubes),
protractors and books (or any objects to establish a consistent
angle), ball bearings, stopwatches.
Procedure:
1. Place 10mL of each chemical in separate pipettes.
Label each one’s contents.
2. Set the pipettes at a 30° angle using the protractors
and other objects. This angel can be increased or
decreased to create a more optimal time (not too fast
and not too slow).
3. Drop a ball bearing into each pipette at the same time
as starting the stopwatch.
4. Record the time that it takes each ball bearing to
reach the same distance in each pipette.
5. Repeat trials as time allows, doing each liquid at least
twice.
Some technique suggestions:
Above: The apparatus for the measurement
of viscosity, with some parts labeled.
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

For accurate distance and timing, drop the ball, let it move until a specific mark (either a mL mark, or
one you tape on yourself) on the tube, start the stopwatch, and stop at another specific mark.
To repeat trials, multiple balls can be used, or the pipette can be tipped back to let the ball return to the
top, or a steel ball can be employed to use a magnet to “drag” the ball back to the top. However, steel
balls may rust over time.
The pipette apparatus can be “permanently” sealed using stoppers, glue, or whatever means, so that
students can simply be given the apparatus, and it reused year after year.
Explain
Teacher presents concepts and vocabulary of intermolecular and intramolecular forces. Possible vocabulary
introduced includes partial charges, polar, nonpolar, hydrogen bonding, dipole-dipole forces, Van der Waal’s forces.
Velcro balls, baseballs and paddles are excellent models to illustrate these concepts kinesthetically. Intermolecular
forces attract the Velcro balls to the paddle. Baseballs lack the attractive forces, so they do not stick to the paddle.
However, if the Velcro ball is thrown hard enough, it too will bounce off, just like adding enough heat to water so that
the particles overcome their attraction and boil.
Elaborate
Students quantitatively measure the evaporation rate of the following substances. They can carry out all steps of the
scientific method, including: developing a hypothesis, writing a procedure, collecting, representing, and analyzing
data, and writing a conclusion. The chemicals listed are a suggested list, but by no means definitive. They represent
several different kinds of forces that will influence their evaporation rate.
 Hexane (adequate ventilation required)
 Acetone
 Ethanol
 Water
 Water with different substances dissolved in it.
Suggestions for a procedure:
 Students can weigh cotton balls, paper, any other absorbent material, or put it on a non-absorbent
surface (because an absorbent material may have different degrees of attraction to the different liquidswhich itself may be an area to spark discussion) add the liquid, and then weigh them again. They can
wait a specified amount of time and re-weigh the items, or time how long it takes for the item to dry.
 Students can wet an absorbent material a certain distance or diameter, and then measure the distance
after an amount of time, or time how long it takes for the entire liquid to dry.
Evaluate
Students will present their findings. Students should come up with data-driven conclusions, address their hypothesis,
critique the strengths and weaknesses of their procedure, propose improvements to their procedure, and suggest further
research that could be done.
Extend
Students connect intermolecular forces with biochemistry in investigating current research being done on protein
folding, DNA structure, and genetics. This research can be done independently and students can present their findings
in the form of a paper, poster, or presentation.
Standards Addressed:
This module addresses multiple content standards according to MPS, Wisconsin, and national benchmarks.
Specifically, these involve science connections, science inquiry, and the structure of atoms and matter. Below is a
thorough list of the standards addressed at these levels.
Science Connections
Milwaukee Public Schools (MPS) Learning Target:
Conduct scientific studies using models, scientific methods, including data collection, analysis, and other
research tools to study systems similar to those found in nature or human made.
Wisconsin State Academic Standards:
Science Connections
A12.3 Give examples that show how partial systems, modes, and explanations are used to give quick and
reasonable solution that are accurate enough for basic needs
A12.5 Show how the ideas and themes of science can be used to make real life decisions about careers, work
place, life-styles, and use of resources
A12.7 Re-examine the evidence and reasoning that lead to the conclusion drawn from the investigations
using the scientific themes
National Content Standards:
Unifying Concepts and Processes: systems, order, organization; evidence, models, explanation; change,
constancy, measurement; evolution and equilibrium; form and function
Nature of Science
MPS Learning Target:
Explain how scientific knowledge is attained. Describe the ethical problems that may result when doing
scientific research. List scientists from various backgrounds and tell about their contributions.
Wisconsin State Academic Standards:
B12.4 Show how basic research and applied research contribute to new discoveries, inventions, and
applications
B12.5 Explain how science is based on assumptions about natural world and themes that describe the natural
world
National Content Standards:
G. History and Nature of Science: Science as a Human Endeavor, Nature of Scientific Knowledge, Historical
Perspectives
Science Inquiry
MPS Learning Target: Research scientific concepts
Undertake scientific investigations using appropriate scientific methods, technology, and tools. Use computerbased technology, mathematics, and scientific vocabulary to communicate results.
Wisconsin State Academic Standards
C12.1 When studying science content, ask questions suggested by current social issues, scientific literature,
and observations of phenomena, build hypotheses that might answer some of these questions, design possible
investigations, and describe results that might emerge from such investigations
C12.2 Identify issues from an area of science study, write questions that could be investigated, review
previous research on these questions, and design and conduct responsible and safe investigations to help
answer the questions
C12.3 Evaluate the data collected during an investigation, critique the data collection procedure and results,
and suggest any ways to make any needed improvements
National Content Standard - A. Science as Inquiry:
Abilities to do Scientific Inquiry (Identify Questions and Concepts that Guide Investigations, Design and
Conduct Scientific Investigations, Use Technology and Mathematics to Improve Investigations and
Communications, Formulate and Revise Scientific Explanations and Models Using Logic and Evidence,
Recognize and Analyze Alternative Explanations and Models, Communicate and Defend a Scientific
Argument) and Understandings about Scientific Inquiry
Structure of Atoms and Matter
MPS Learning Target:
Diagram the structure, and analyze the chemical reactions of elements. Explain the forces that hold the atom
together, and how nuclear interactions change it. Describe the difference between chemical reactions and
atomic reactions.
Wisconsin State Academic Standards
D12.1 Describe atomic structure and the properties of atoms, molecules, and matter during physical and
chemical interactions
D12.2 Explain the forces that hold the atom together and illustrate how nuclear interactions change the atom
D12.4 Explain how substances, both simple and complex, interact with one another to produce new substances
D12.5 Identify patterns in chemical and physical properties and use them to predict likely chemical and
physical changes and interactions