Procedure

The track was set up first with a lane timer that measures to .001 of a second.  For each test, the cars made at least 5 runs.  I took out the high and low times and then averaged the rest.  All tests were run in the same lane of the track.  I only want to test modifications that will be legal in Cub Scout races.  (See the official rules from the Pinewood Derby Kit.)

Test 1: Baseline:  I tested three cars with no modifications other than adding weight to make them all 5 ounces each to find a baseline time.  We poked screws in the sides of the cars to balance them.  We had the weight in the center of the cars for all the baseline tests.

Test 2: Stress:  Next we ran one car 50 times to see if the parts would wear in and go faster, or wear out and go slower. Blank chart

Test 3: Graphite Baseline: We put graphite on the axles of the three cars and timed them to get a baseline time with graphite.

Test 4: Graphite Stress:  For this test, we put a lot of graphite on the axles of one car and ran it 50 times to see if the car would run faster after a few races.

Test 5: Weight & Axle Location:  We raced a car with the weight (center of balance) closer to the front and then closer to the back.  Then we raced the car with the axles more toward the front and again more toward the back. Blank chart

Test 6: Aerodynamics:  We cut a slot in the top of a car and put in a 3x5 index card to see if the wind would slow down the car.  Then, we cut the front of the car into a point to see if the car would go faster.

Test 7: Wheels:  We put the wheels in a drill and sanded them to make sure they were smooth and round.  Then, we waxed the wheels to make them slippery.  We pushed in the axles more so they would only stick out 1/16 of an inch.  Then we pushed the axles in more to about 1/32 of an inch.

Test 8: Alignment:  We rolled one of the cars on a table.  Instead of going straight, it turned about 3 inches in 3 or 4 feet.  We timed that car several times, then adjusted the axles so the car rolled straight on the table.  Then we timed the car several more times.

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