wiki Word: friction Definition: A force that resists the motion of two surfaces against each other

Include any facts, details, examples, questions, etc. that might help students understand this vocab word.  Friction is the force that opposes the movement of an object in motion. Friction acts in the direction opposite of the object's direction in motion. Without friction, the object would continue to move at a constant speed forever. There are different forms of friction. Sliding friction is when two surfaces slide one over the other. (EX. Snowboarding). When an object rolls over a surface, the kind of friction that occurs is rolling friction. (EX. skateboarding) Friction also occours in fluids (liquids and gases). This type is called fluid friction. (EX. swimming and surfboarding). There is also many more such as air resistance. Friction is both good and bad. Friction makes it hard to move a heavy object such as a refrigerator or a large box. Friction makes it possible for people to walk by allowing shoes to push off the ground without slipping. On other surfaces, such as ice, you would slip and slide around due to lack of friction. No surface is completely smooth. Like a table or a counter top may seem smooth, but if you were to look at it under a microscope, you would see the ruggedness of the surface. This is what causes friction.

Insert an image here   These two surfaces (such as a counter top and a pan) may appear perfectly smooth, but no surfaces are perfectly smooth. This is what causes friction.

How does this term apply to any of our class labs? We have witnessed friction in the air rocket car lab. If the wheels on our cars weren't smooth, this would have caused more rolling friction. We also saw air resistance in this lab. This would have slowed the car down also.  Also, in the Air Bottle Rocket Lab, the friction of the bottle as it was shooting upward (along with gravity) caused the bottle to come back down and slow down.

Cite any sources used for the information on this page. *Westbroek, Glen. "Pull You/ Push Me." 08 07 2000 January 30, 2008   *"Friction." Wikipedia. 2008. 2 Feb 2008 <http://en.wikipedia.org/wiki/friction>.   * The Friction Image came from: Marffy, Janos. "Friction." 3 of 88. Feb. 26 2008 <http://www.dkimages.com/discover/previews/831/20114084.JPG>.    Katherine, 2nd period