Thames & Kosmos DLX, Experiment Manual, Page: 82 / 132

Car slalom
YOU WILL NEED
› The assembled car
› IR remote control
› 5 AA batteries or 5 AA rechargeable batteries
› Gate poles (made of red gear wheels and motor shafts)
› Measuring tape and masking tape
› Pocket calculator
› Stop watch, note pad, and pen
HERE’S HOW
1. Build a slalom course using four red gear wheels with
motor shafts spaced 50 centimeters apart in a single
line (or a different layout if you wish).
2. Mark the start and finish lines with masking tape. The
starting line is just to the right of the first gate and the
finish line just to the left.
3. Drive the car to the starting point. Ask someone to
operate the stop watch, preferably one of the other
competitors. On your marks, get set, go!
4. Now zigzag between the gates with the stop watch
running. At the last gate, turn back to the starting point
WHAT’S HAPPENING
If you measure the length of your slalom course (or the tightest line that you can take around the gates) and keep
track of the time it takes to complete it, you can calculate the speed of your car.
As an example, let’s take these two values:
››› distance driven: 240 centimeters or 2.4 meters
››› time needed: 20 seconds
In meters per second, that equals a speed of 2.4 m / 20 s = 0.12 m/s.
But driving speed is typically calculated in km/h, or kilometers per hour, in the scientific
community (and in mph, miles per hour, in the United States.) To convert m/s to km/h, you
will first have to know that a kilometer is 1,000 meters. One hour is 3,600 seconds. So we can set up this
equation: One kilometer in one hour = 1,000 meters in 3,600 seconds. It’s easier and clearer to write that in
terms of fractions with shorter numbers: 1 km/h = 10 m / 36 s or 1 km/h = 1/3.6 m/s.
And that gives us the factor by which we have to work when converting km/h
and m/s: 3.6. When converting m/s to km/h, then, we multiply the m/s value by 3.6.
In our example, that means that our slalom car drove at a speed of 0.12 x 3.6 = 0.432
km/h. You can also use this same formula to calculate the top speed of the sports
car in Experiment 15. Now, can you find out how to convert m/s into mph?
and slalom back around the gates in the opposite
direction.
5. At the end, you will cross the finish line just to the left
of the first gate. Then it’s your opponent’s turn.
DID YOU KNOW?
Slalom competitions are held in the
sports of snow skiing, canoeing,
water skiing, and wind surfing, as
well as snowboarding and skateboarding.
EXPERIMENT 12
80