Monster Trucks: Reading and Sketching Graphs
Pre-Lab
First demonstrate the trucks to the class. Use the following questions to
lead the discussion. Allow the students to work by themselves or in groups
to answer the pre-lab questions.
1. Watch the teacher demonstrate a pullback truck in motion. How do you think
the truck works?
Pull back one of the trucks and let it go across the floor or table. Ask
students to write down their ideas about how they think the truck works.
After discussing student ideas, tell students that there is a coil spring
inside. When the wheels are pulled back, the spring tightens. The energy
stored in the tightened spring causes the truck to move when the truck is
released. Compare the spring to wind-up toys, a gag hand buzzer, etc.
Demonstrate the gearing mechanism to students. For each turn the wheels
are wound up, they unwind about seven turns. So pulling the truck back a
small amount can make it go a long way. If you have internet access in the
classroom, this web site shows pictures of the coiled spring inside of a
wind-up clock that runs on a similar principle:
http://home.howstuffworks.com/inside-clock.htm
2. Energy is required to move anything. Where does the energy come from in
the pullback truck?
The energy comes from pulling the truck back. Pulling the truck back
tightens the coil inside, storing energy. It’s similar to stretching a rubber
band. When the truck is released, the energy stored in the coil causes the
truck to move forward.
3. List at least one factor you think makes truck go
a) faster
b) farther
Give the student groups a few minutes to discuss the questions and write
their responses. Ask each group for a response to each question. Keep a
running tally of student responses on the overhead or blackboard. Some
group responses may include a stronger spring for more energy, bigger
wheels for more traction, etc.
4. If a car in California and a car in Germany both claim to be the fastest car in
the world, how can you tell which car is the fastest?
Monster Trucks: Pre-lab
Teacher Notes
© 2004 The University of Texas at Austin and the GE Foundation
Page 1 of 3
Assume the cars can’t be brought together for a race. Get students onto
the idea of measurement and measuring the speed of each car.
5. A common speed limit is 45 miles per hour. What does the “miles per hour”
part mean?
Miles per hour can be discussed as a rate of change or distance per unit of
time.
6. What two quantities do you need to measure in order to calculate miles per
hour? What do you need to measure in order to calculate meters per
second?
Distance in miles and time in hours
Distance in meters and time in seconds
7. What “speed” formula can we make for the trucks?
Speed = Distance / Time
8. Your teacher will demonstrate measuring distance and time using the truck.
How fast did the truck travel in inches per second?
Show students how to pull the truck back to a starting line marked with
masking tape before letting it go. Ask for a student volunteer to measure
time and another to measure distance. Write the distance and time on the
board.
Answers will vary. Example:
Speed = Distance / Time
Speed = 55 inches/5 seconds = 11 inches/second
9. If a toy car went 6 meters in 3 seconds, how many meters per second was it
traveling?
Speed = Distance / Time
Speed = 6 meters / 3 seconds = 2 meters per second
Monster Trucks: Pre-lab
Teacher Notes
© 2004 The University of Texas at Austin and the GE Foundation
Page 2 of 3
10. If the fastest human can run almost 23 miles per hour, how long would it take
her to run a marathon (26.2 miles) assuming she can keep her top speed the
entire distance?
Time = Distance/Speed is another form of the equation.
Time = 26.2 miles/ 23 miles per hour = 1.14 hours
or 1 hour 8 minutes 24 seconds
Monster Trucks: Pre-lab
Teacher Notes
© 2004 The University of Texas at Austin and the GE Foundation
Page 3 of 3