INVESTIGATION: Why do some things stick together and other things do not?
Overview
Have you ever noticed that, sometimes, even things with no glue on them can stick together? This does not
always happen, though. In this investigation, you will develop a model that helps you explain why some
things stick together and other things do not.
Guiding Question
Why do some things stick together and other things do not?
Guiding Standards
Georgia Performance
Standards - Content
SPS10. Students will
investigate the properties of
electricity and magnetism.
a. Investigate static
electricity in terms of
○ friction
○ induction
○ conduction
Science & Engineering
Practices
●
●
Developing and
Using Models
Engaging in
Argument from
Evidence
Crosscutting
Concepts
●
●
Patterns
Cause and Effect
CCGPS Literacy
L9-10RST1: Cite specific textual
evidence to support analysis of
science and technical texts,
attending to the precise details of
explanations or descriptions.
L9-10WHST1:
Write arguments focused on
discipline-specific content.
Activity 1: Sticky & non-sticky things
What does electricity have to do with things sticking together or flying apart?
Watch the videos and demonstrations shown by your teacher. Think about what happened in these cases before
answering the questions below.
1. What causes these things to stick together? Brainstorm with your partner and jot your ideas below.
2. What questions do you have about these items sticking together?
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Your teacher will now demonstrate the function of a machine called a Van de Graaff generator, and then what
happens when pie pans are placed on the Van de Graaff generator
3. How do you think sparks form?
4. What questions do you have about sparks?
5. Your teacher will now conduct the pie pans demonstration. What do you think will happen? First record your
prediction below. Then record your observations and your initial explanation.
Prediction (What do you think will happen?)
Observations (What actually happened? Be as specific as possible.)
Explanation (Why did this happen? Do your best, and don’t worry about being wrong.)
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Activity 2: Getting a charge out of tape
What are some patterns in how things stick together or push apart?
In the last activity, you observed some examples of objects sticking together (attracting) or pushing away from
each other (repelling). How can you predict which objects will stick together and which ones will not? In this
activity, you’re going to explore how strips of tape interact and analyze your observations to see if there are any
patterns in the way they interact.
Materials
● Scotch tape
● pen or pencil for labeling
Investigate
Each partner will follow the steps below.
1. Get a strip of tape that is 1.5 to 2
inches long. Fold over one end of the
tape as shown in the figure above.
This will give you a non-sticky
handle to hold the tape with.
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2. Stick this piece of tape to the
desk, and label the handle “B,”
for bottom.
3. Get a second strip of tape that is
1.5 to 2 inches long, and fold it in
the same way. Place it directly on
top of the first piece of tape, and
label the handle “T,” for top.
4. Using the handles, lift both pieces
of tape off the desk at the same time.
Then touch the entire length of the
strip on both sides with your fingers
several times. This will remove any
electric charge on the surface of the
tape.
5. Pull the pieces of tape apart,
making sure to not touch the
tape anywhere except on the
non-sticky handles you made.
6. Both pieces of tape are now
charged. Experiment with your
partner to see how the pieces of tape
interact with each other when you
bring them close together in
different combinations.
Tip: Try not to let the pieces of tape touch each other. If they do touch a little bit, they will lose some of their charge.
1. Write your observations of what happens when you bring the pieces of tape close together in each combination
(T-T, B-B, and B-T).
2. Based on your observations, what patterns can you identify when two pieces of electrically charged tape are
attracted to each other and when they are repelled?
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What’s the charge, anyway?
A Van de Graaff generator works by separating charges
through friction. As the rubber belt slides over the metal
rollers, charge is transferred from one to the other.
Negative charges are transferred down, away from the
metal sphere at the top of the generator. This leaves the
metal sphere with a positive charge. Using this knowledge,
you will now determine which pieces of tape (T or B) show
which charge (positive or negative). [Image from
http://en.wikipedia.org/wiki/Van_de_Graaff_generator]
3. For each piece of tape, record its behavior when held next to the
Van de Graaff generator. Then determine the charge for each piece
of tape
Top (T) Tape
Bottom (B) Tape
Observation:
Observation:
Inferred Charge:
Inferred Charge:
Activity 3: Developing a model of the Van de Graaff pie pan demo
Why do the pie pans fly off the Van de Graaff generator?
Scientists try to explain observations or phenomena. Models are a very useful tool that scientists use to
communicate and show underlying causes. Models are useful for explaining and making predictions about
phenomena. You will create your own model to explain why the pie pans flew off of the Van de Graaff generator.
As you develop your model, be sure to think of the three aspects of modeling:
● Components - Models are simplifications of phenomena, so they do not show everything. However, they
must include key components. Some components may be what you see in the phenomena, but some may
be invisible underlying causes.
● Relationships - How are the components related to each other? How do they interact with each other?
● Connection to a phenomenon - The relationships between the components should help you explain
observations or make predictions.
1. Start by identifying the important components to include in your model.
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2. Now that you've seen what happens to the pie pans after the Van de Graaff generator is turned on, make two
drawings on your whiteboard to show what caused the pie pans to behave the way they did.
3. Label your drawings and explain what is happening at each step so that anyone can understand your drawings.
Once everyone has completed their initial models, we will share these anonymously with the class and discuss the
similarities and differences among the models.
Incorporating scientific ideas
4. We have observed and discussed several important scientific concepts, but we need to be sure we have some
common descriptions and terms for these concepts. Use the chart on the next page to take notes on these key
concepts as you read pages 430-434 in your textbook.
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Concepts of Electric Charge and Force
Concept
electric charge
conductor
insulator
charging by
friction
charging by
conduction
(contact)
charging by
induction
electric force
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Example from lesson
Description (In your own words)
Illustration
Improving models of the pie pan demo
Think back to the Van de Graaff aluminum pie pan demonstration you saw at the beginning of this investigation.
Think about what you’ve learned since you first saw this demonstration and how you can use that knowledge to
explain what caused the pans to behave the way they did. Use the graphic organizer below to record your revised
model and explanation.
Question What caused the pie pans to fly off the Van de Graaff generator?
Evidence (Data, observations, facts, or other scientific information that you can use to answer our question)
Opening Demos/Videos
Tape Investigation
Model Discussion
Charge & Force Reading
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Claim (A clear and direct statement based on the evidence and answering the question)
Model (Your model should include the key components of the phenomenon and the relationships among those
components. Your model should help you explain and make predictions about the phenomenon.
● Create a series of drawings that show why the pie pans behaved the way they did.
● Be sure to include a mechanism (“how it works”) that could explain what caused the pie pans to fly off the Van de
Graaff generator.
● Label your drawings and explain what is happening at each step so that anyone can understand your drawings.
Reasoning (This is where you tie everything--your evidence, your claim, and your model--together to explain what is
happening and how you know what is happening.)
The evidence shows… (Summarize the key patterns or ideas from your evidence.)
I know that… (Review the key concepts of charge and force that helped you develop your claim.)
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I can apply… (Explain how the crosscutting concepts of patterns and cause and effect helped you develop your
claim.)
Therefore, I can conclude that… (Tie it all together. )
Enrichment Activity: Applying your knowledge to win a game
In the past several activities, you’ve developed a model that can be used to explain and predict how charged
objects interact with each other. Now, apply what you’ve learned and test your knowledge about interactions
between charged objects by playing the Maze Game.
1. Your goal is to move the white ball to the target area before time runs out.
2. Click Run. Then click (–) to put a negative charge on the white ball, (+) to put a positive charge on the
ball, or (0) to make it neutral.
3. When you are finished, take a snapshot as proof you won the game.
Simulation link: http://lab.concord.org/interactives.html#interactives/interactions/mazeGame.json
1. Email a snapshot of your winning game to your teacher.
2. Write about a real-life experience with static electricity that includes a description of how charges played a role
in what you observed.
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