1. Friction

2. Friction  Friction is defined as a force that opposes the motion of objects that touch as they move past each other. Friction is the interaction between two surfaces.  There are 4 main types of friction: Static, Sliding, Rolling and Fluid.

3. Static Friction  Static Friction is the friction force that acts on objects that are not moving.  The object is not moving because the force of friction is greater than the force applied by natural forces or your big muscles. So…the object stays where it is. “The force that keeps an object that is not moving in its place". A vase on top of a table is an example of static friction.

4. Sliding Friction  Once an object starts moving, sliding friction takes over. Sliding friction opposes the movement of an object, and makes it slow down and/or stop.  For example: When you ski down a slope and end up on the flat part of the hill. It is the sliding friction that makes you stop. Sliding Friction: "the force that occurs when two objects slide against each other". An example of sliding friction is striking a match against a rough surface.

5. Rolling Friction  Rolling friction is the friction force that acts on rolling objects. Rolling friction is 100-1000 times less than the force of static or sliding friction.  Ancient people used rolling friction to move huge blocks of stone to build the pyramids. We use it today in wheels for skateboards. The bearings in the wheel provide rolling friction. Rolling Friction: "slows down the motion of an object rolling on a surface". Rolling friction slows down the motion of a tire rolling along the pavement

6. Fluid Friction  Fluid friction opposes the movement of an object through fluids and gases. Fluid Friction is also called air resistance.  Air resistance is the reason feathers fall so slowly. It is the reason skiers tuck when racing.  You feel fluid friction when you try to run in water. Fluid Friction: "the force that slows down an object when it travels through air or a fluid". A fish swimming in the water is an example of fluid friction.

7.  Friction is a beautiful thing. It is the reason we can walk, sit and move.  What would the world look like with no friction…..  When there is no friction video.asx When there is no friction video.asx When there is no friction video.asx