some of the energy that would otherwise go into
moving the car forward. Similarly, the bumps on the
mesh shelf liner shake the car, which also diverts
energy from moving the car forward. This is why the
cars on these two tracks move more slowly.
This activity encourages measurement of both speed
and distance. While younger children will judge
speed and acceleration based on visual perception,
older children can clap at regular intervals to mea-
sure the time a car takes to reach the bottom of each
track. (In this case, they will need to race the cars one
at a time.) A metronome, which produces sounds
and light flashes at regular intervals for musicians to
follow, is even better to use. These devices are not ex-
pensive and can be used in a variety of activities. The
gridlines along the floor help children begin to quan-
tify measurements of distance. Children can also link
together manipulative materials, such as snap blocks,
to measure distance. This helps children realize that
measurement involves use of a designated item as a
unit, and the number of units used is the distance.
Children will likely want to discuss the order of
finish of the cars, which leads to the learning and
application of ordinal numbers—fi rst, second, third,
and fourth. They may even want to record the order
of finish on a score sheet.
Connections to Technology
Use of a digital video camera to preserve some of the
ramp experiments allows children to review the re-
sults and the teacher to lead discussions with groups
of children. As children watch the cars move down
the various tracks, they can together clap and count
pulses to determine speed. Children can also com-
municate about the experiments and share their infer-
ences regarding what affects the speed of the cars.
Understanding how the surface of roads affects
speed is important to civil engineers. Sometimes
curves on a steep road have ridges to help prevent
vehicles from going too fast. Teachers can intro-
duce these concepts through their discussions with
children. Comments and Questions
to Support Inquiry
• Does the car on the wood ramp always get to the
bottom first? Why do you think that happens?
• This time let’s watch for the car that comes in third
place. • Can you predict which car will go the farthest?
• Does the fastest car always go the farthest?
• Does the slowest car always go the shortest
distance? COPYRIGHTED MATERIAL
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