1. Friction
- An introduction

2. What does the word “friction” mean in the following statement?
Usually we work so well together as lab partners, but lately I feel like there’s a lot of friction between us.

3. Friction is a force that opposes motion between two touching surfaces.

4. -- At a microscopic level, even the smoothest surfaces have rough edges and friction is created

5. A closer look at why there is friction
Magnified view
of surfaces
At the microscopic level even two smooth surfaces look bumpy  this is what produces friction

6. There are three basic types of friction:

7. 1. Sliding Friction
-occurs when two surfaces slide directly on top of one another
ex. trying to push a filing cabinet across the floor.
--creates strongest frictional force

8. 2. Rolling Friction -- ex riding a skateboard across the floor
-occurs when one object rolls on or across another
-- ex riding a skateboard across the floor
-- wheels decrease frictional force, less surface area touching

9. 3. Fluid Friction - occurs between an object and a fluid
-- like an ice skater
-- also an airplane flying through air, the air molecules have fluid friction

10. Friction: Friend or Foe??
Helpful Friction
- we couldn’t walk without it!
- friction between pen and paper or a bat and a ball
- wearing cleats to play sports increases friction
Not-So Helpful Friction
- wind and water cause “erosion” of land
- holes in your worn out clothes or shoes
- air resistance slowing down your airplane flight and causing greater fuel usage

11. The Springscale Instrument used to measure force
Units are Newtons or grams WE WILL USE NEWTONS WHEN WE USE A SPRINGSCALE!!
Intervals may vary between different springscales N

12. What direction is the friction force? What type of friction is it?
Complete worksheet: Forces of Friction
What direction is the friction force?
What type of friction is it?

13. What direction is the friction force? What type of friction is it?
Motion is downward
What direction is the friction force?
What type of friction is it?
So friction
is upward!

14. Leaf falling against the air means
FLUID FRICTION
Motion is downward
So friction
is upward!

15. SLIDING FRICTION
ROLLING FRICTION

16. FLUID FRICTION
FLUID FRICTION
FLUID FRICTION

17. FLUID FRICTION
ROLLING FRICTION
ROLLING FRICTION

18. What are the factors that affect friction?
In other words, how can we increase or decrease the amount of friction between objects????