## 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.

• The wind-up from Lesson 4
• Make a new wind-up as in Lesson 4, but with paper saucer wheels.
• Prepare a chart of materials needed for the large wheel wind-up.

## Materials

• Materials for making the third wind-up: these are the as used in Lesson 4, but with  paper plates for wheels.

## Procedure

1.      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?

2.      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.

3.      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?

4.      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.