1. Science Ch. 5 Lesson 3 By Grace O’Doherty

2. Friction: A Force that Opposes Motion friction is a force that opposes motion between two surfaces that are touching friction occurs because the surface of any object is rough (even for those that appear smooth) the amount of friction between two surfaces depends on the roughness of the surfaces and the force pushing the surfaces together

3. Force Exertion Also Matters friction also has to do with how much force is exerted on on object greater force creates a greater amount of friction if force is increased there is more contact between the two surfaces

4. Four Types of Friction the four types of friction include: sliding, rolling, fluid, or static

5. Sliding Friction sliding friction is difficult to overcome,therefore, a lot of force must be exerted sliding friction is the force that gets the objects to stop moving examples of sliding friction include: applying the breaks on your bike, sliding an eraser across your desk, or even writing with a piece of chalk

6. Rolling Friction the force of rolling friction is less than that of sliding it is generally easier to move objects on wheels than it is to slide them examples of this force include: wheels on a bike, a train, or a car

7. Fluid Friction fluid friction is also less than sliding friction fluid friction also includes liquids and gasses this type of friction opposes the motion of objects traveling through fluid

8. Static Friction static friction occurs when force is applied to an object but it doesn’t move static friction dissapears as soon as an object starts moving

9. Friction Can Be Harmful or Helpful without friction, a car is useless however, in a car, friction can cause the parts to wear down from an increase in tempreature without friction, you could not do your homework or even play sports friction can also put holes in your socks and blue jeans because of these harmful and helpful effects, we sometimes need to reduce or increase friction

10. Some Ways to Reduce Friction one way to reduce friction is through lubricants (substances that are applied to surfaces to reduce the friction between them) you can also reduce friction by switching from sliding to rolling friction

11. Some Ways to Increase Friction you can increase friction by making surfaces rougher when you do this, you can pour sand on an icy road or even wear a textured batting glove another way to increase friction is by increasing the force pushing the surfaces together