The Pinecrest Street Race
by Max L.
8th Grade - 3rd Place

Question: What surfaces make Hot Wheels go faster?

Hypothesis: This researcher thinks that the Plexiglas will move the Hot Wheels down the racetrack faster, because the Plexiglas seems to have the smoothest surface, which reduces friction.

Discovery: When the cars rolled down the 5 lanes which all had different surfaces it had an astonishing finish with both the Plexiglas and the wax paper tying at first place, then the linoleum at 2nd place, the sandpaper in 3rd place, and the rug at dead last. All the cars started at the same time, but why did they have different speeds? The answer to your question is friction. Friction is the surface resistance to relative motion, as of a body sliding or rolling. No surface is so smooth that it has no friction. All surfaces have tiny
cracks, valleys, and hills, but are just too small to see with the naked eye. It requires energy to get out of the hills, valleys and cracks. The more friction the harder it is to get out. Without a constant supply of new energy to get it out of the hills, valleys, and cracks, the car will slop and lose the battle to friction.

With the wax paper and the Plexiglas tying at 1st, the only reason I could see why they would tie is because the wax paper had a bottom of Plexiglas and just a little bit of wax paper on top. The bottom helped the wax paper be able to keep the car at a fast pace resulting in a tie with the Plexiglas by itself. If you look at the rug and the sandpaper you can see why they were the two last place finishers. Both had hills, valleys, and cracks that were actually seen with the naked eye. Those valleys, cracks, and hills made sure that the cars would have to use more energy to get past them, resulting in slower speeds.