Energy systems
Fantastic Elastic
6 Experiment on  Wheel size: Preparations
Overview
Students plan how to do an experiment that will compare wheel size. They plan the data sheet. They make a new wind-up the same as in Lesson 4, but with larger wheels.
Procedure
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Class meeting. The purpose of the meeting is for students to consider the variable of wheel size and to plan an experiment to find the effect of wheel size. Display a wind-up with paper saucer wheels and a windup with the cup lid wheels from Lesson 4.
- What difference do you think the size of our wind-up wheels makes in how the wind-ups will go?
- Which wind-up do you think will go farther, the one with bigger (paper saucer) wheels or the one with the smaller paper cup wheels?
- How can we do this experiment? Elicit the idea that they will each need to compare two wind-ups with different size wheels. They already have the wind-ups from Lesson 4. How should they make a second wind-up? What wheels should they use? Does it matter what cup they use? What rubber bands? Reinforce the idea that to be a fair experiment, the wind-up they make must be the same as the one made in Lesson 4, except for the wheel size.
- How will you know how far each wind-up goes?
- How will you measure it?
- How will you write down your results?
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Students make wind-ups with paper saucers as wheels. Post a list of materials for this wind-up. Have students get materials and build wind-ups. Walk around the class to help any who have issues.
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Class meeting. The purpose of the meeting is for students to talk about the experiment they will do in the following period. How many think the paper saucer wind-up will go farther? How many think the smaller wheel wind-up will go farther?
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Outcomes
- Students plan an experiment to compare the distances that wind-ups having different sized wheels will go.
- Students construct a comparison wind-up with large (paper saucer) wheels.