Science Buddies: "Ask an Expert"

I have a project about which surface has the least friction. I would be using the surfaces wood, cardboard, and carpet. I would be testing for time. I don't know how to set up the hypothesis. Should I just put that I predict that smooth wood has the least amount of friction?

Sounds like a good project! Here is a good resource for writing your hypothesis.

http://www.sciencebuddies.com/science-f ... esis.shtml

audreyln wrote:Sounds like a good project! Here is a good resource for writing your hypothesis.

http://www.sciencebuddies.com/science-f ... esis.shtml

Thanks. Do you think this is a good hypothesis?
If use a finished surface, than the amount of rolling friction would be lower than a rough surface.

MonkSage wrote:If use a finished surface, than the amount of rolling friction would be lower than a rough surface.

If you still plan on testing wood, cardboard, and carpet surfaces, then I'm not sure how you would define these surfaces as "finished" or "rough".

With materials that will compress and stretch when you roll an object over them, the coeficient of friction for the test sample will likely change with different pressures (normal or downward force divided by surface area) and will likely be affected by the shape of the roller.

If the cardboard is corrugated, then both your cardboard and carpet will compress and stretch significantly more than your wood sample.

This will likely make your hypothesis hard to prove because there will likely be more than one factor involved in any differences.

Thanks for the info. I changed my project a little bit. The surfaces I used were smooth wood, aluminum foil and paper. I used a toy car to test the hypothesis.
Will this hypothesis work for the experiment?

If I use a smooth, unwrinkled surface, then the amount of friction would be less than using a corrugated surface. Therefore, the smooth wood would have less friction than the aluminum foil and paper.
But the results contradicted my experiment. Aluminum foil had the least friction and smooth wood was the second.