Students will present their projects at the science fair. Each write-up will receive a grade Experimental work product will be evaluated for accuracy, thoughtfulness and effort. Reason - Friction the force that acts when two objects rub together or slide over one another. Friction keeps objects from moving . In the above example the friction between the soles of shoes and ice is less than the shoe soles and the ground.
Smooth surfaces make less friction than rough surfaces .
It takes more force to move an object over a rough surface than a smooth surface. This may be demonstrated with a ten pound plate, string, and a towel. Friction can be useful, for example people used it to make fires. Too much friction makes heavy objects hard to move. This can be done using chains or sand they make the touching surfaces more rough.