1. Friction

2. Four Types of Friction: 1.Static Friction: -- Friction when an object is at rest. -- Due to the microscopic bumps and grooves on the two surfaces locking together. -- Causes the most friction of the four.

3. 2.Sliding Friction: -- Friction when an object is in motion on a surface. -- Also, due to the microscopic bumps and grooves on the surfaces, but this time sliding past each other. --Causes the second most friction.

4. 3. Rolling Friction: --Friction when an object rolls over a surface. --An object rolls when friction on the bottom of the object causes it to tip over. -- Much less friction than static or sliding.

5. 4.Fluid Friction: -- Friction due to an object sliding over a surface with a lubricant or moving through air or water. -- Air resistance is a form of fluid friction. -- This is the form of friction that is the least strong.

6. Friction Activity 1. Find three other people in the room with different type shoes than you. 2. Using a spring scale, determine how much force is required to pull a shoe across the table at a constant speed. -Watch the scale carefully, does it take more force to get the shoe moving, than to keep it moving? 3. Repeat with one of each type of shoe. 4. Record your results on a data table. 5. Try each shoe again with mass added to it. Record your results. 6. Write summary of your results. What can you conclude?