2. AIM: What is friction? Describe different types of Friction. Define the parts of a spring scale.

3. Spring scale, pointer, spring, hook, friction, sliding friction, air resistance, rolling friction AIM: What is friction?

4. What is the basic unit of measure of length in the metric system for length? Meter What is the basic unit of measure for mass in the metric system? Gram What is the basic unit of measure for volume? Liter

5. What is the basis unit of measure for force? the NEWTON … N On earth it take a force of approximately 10 N to lift a 1 Kg object

6. What is Friction? Definition: Friction is the force which opposes the motion of an object. EVERYBODY: Push your notebook across the table. Why does it stop?

7. Three types of Friction: 1. Sliding Friction, 2. Rolling Friction, 3. Air Resistance

8. DEMONSTRATE: Sliding Friction Push a chair across a room. Does it stop? Why: Sliding Friction

9. DEMONSTRATE: Rolling Friction Slide a rolling chair across the room. Does is stop? Eventually But does it move farther with the wheels then without? Absolutely

10. DEMONSTRATE: Air Resistance Drop a flat piece of paper Drop a crushed piece of paper Can YOU explain why the flat piece took longer to reach to ground.

11. Is friction bad? Without friction, it’d be like walking on ice Imagine peddling your bicycle on ice. Or wearing smooth soled shoes while playing basketball?

13. What is “that hand” holding? … a spring scale

14. Parts of Spring Scale Hook Pointer Spring

15. Is this a spring scale? YES. Most scales are spring scales! DON’T confuse a scale with a triple beam balance. They are two different things.

16. ** Activity: Using a Spring Scale. 1.Mass a book and several other small objects. 2.What is the weight of the book? 3.What are you measuring when you when you weigh an object? (gravity) How much force (measured in N’s) does it take to lift a 1 Kg object? 10 Newtons

17. REVIEW VOCABULARY – AND THE AIM – AND THE OBJECTIVES

18. Define the parts of a spring scale. Hook, pointer, spring Describe three different types of friction: Sliding, rolling, air resistance

19. Class Activity: W/S Concepts 2-3, 2-5

20. Homework: INTERNET QUESTIONS FINISH W/S