"Betty Builds a Better Racer," found in the
Adventure Book, describes Betty's attempts to find
the best design for the car she will enter in a soap
box derby. Using the same techniques students will
explore in the lab in Part 2 of this lesson, Betty
methodically changes one design element at a time
trying to find the design which will result in the farthest
roll. The story provides opportunities for discussing
controlled variables and the effect of
changing variables in an experiment. Use the
prompts to guide discussion about the story.
Page 1
- What is a soap box derby? (A soap box derby is a
race in which the contestants make cars without
motors and race them downhill.)
Page 3
- What is the meaning of the word streamline? Students might describe streamline as changing the
shape of the car to make it go faster. You might point
out that one reason racing cars are low to the ground
is to make them go faster.
- Which is more streamlined—a bus or a race car? (race car)
- Which goes faster? (race car)
- Why do you think so? (A race car is more streamlined than a bus.)
Page 5
- What is Betty doing? (She is building a ramp to test how far her car rolls.)
Page 6
- How will lining the ramp up with the sidewalk
crack and marking a line on the ramp help her test
her car? (Betty said she was going to try different
wheels and change the body shape to make the
car go faster. If she always keeps the ramp in the
same place and uses the same starting place, she
can make many rolls and tell which change
makes the car go farthest.)
Page 8
- Should Betty and Tom push the car? (No, they
should not push the car because they will not be
able to push with the same force each time. They
should just let it roll.)
Page 10
- Why does Betty want to change the wheels on
her car? (She thinks the new wheels might help
the car go farther.)
Page 12
- Which wheels were better, the first or the
second set? (The second set; the car rolled one
space farther.)
Page 13–14
- How does Betty's car change between the pictures on these two pages? (Betty adds boards to change the
shape of her car.)
Page 15
- How far did Betty's car roll after she streamlined it? (9 spaces)
- Was that farther than after she changed the wheels? (Yes, 3 spaces farther.)
- How did you find out? (I counted on from 6 to 9.)
- What did Betty do to build a better racer? (She
changed the wheels, streamlined the body, and
sanded it.)
