### Lesson Summary

### Overview

In this *Cyberchase *activity, students solve the rate-time-distance equation, d = rt, and they use graphing to figure out how the CyberSquad can catch Wicked before she reaches Motherboard. In doing so, students practice solving the equation d=rt for different variables.

### Grade Level:

4-8

### Suggested Time

one hour

### Media Resources

A Race to Motherboard QuickTime Video

### Materials

Intercepting the Wicked Witch handout

Assessment: Level A

Assessment: Level B

Answer Key

### The Lesson

### Part I: Learning Activity

1. Read the following to your students, The CyberSquad needs to figure out how to catch Wicked before she attacks Motherboard. Wicked travels on a broom at a constant speed of 50 cybermeters per second. Motherboard is located at a distance of 400 cybermeters away. The CyberSquad leaves x seconds after Wicked. How fast must their broom go so that they can reach Motherboard before, or at the same time, as Wicked?

2. Distribute the Intercepting the Wicked Witch handout.

3. Ask the students to complete the handout. Focus on ensuring that all students draw a straight line segment from (0, 0) with a slope of 50 cybermeters per second, ending at (120, 6000). Their graph for the Cyberchase kids must have a slope of 100 and intersect Wicked's distance-time graph at or before 6000. Be certain that students do not mistake the line segments on the distance-time graph for the actual path traveled, which is a common misconception.

4. Discuss student results from handout.

5. Tell the students that they will now watch a video clip in which the CyberSquad figures out how to reach Motherboard before Wicked does. Tell the students that as they watch the video clip, they should compare the CyberSquad's solution to their own.

6. Play the A Race to Motherboard QuickTime Video.

7. Discuss the students' solutions, as well as the ones shown in the video clip. Be sure students are able to work with multiple forms of the equation d = rt (r = d/t and t = d/r).

### Part II: Assessment

Assessment: Level A (proficiency): Students are asked to use the rate-time-distance equation, d = rt, to complete a table of times and rates for different distances.

Assessment: Level B (above proficiency): Students are asked to use the rate-time-distance equation, d = rt, to find the winner in a race between a Tortoise and a Kangaroo. Students are asked to determine the shape of a distance-time graph when the speed is 0.