Forces

Chapter 11Energy and Simple Machines

I. What is energy?

a. Energy is the ability to do work

II. What are the six forms of energy?

a. Light Energy- light bulbs

b. Sound Energy- radio, voices

c. Heat Energy (thermal)- sun, light bulb

d. Electrical Energy- vacuum, tv

e. Mechanical Energy – bike, car

f. Chemical Energy- food, gasoline

III. How can energy change?

• from one form to another

a. Light bulb – light energy changes to heat energy

b. Blender – electrical energy to sound energy

c. Rub hands – mechanical energy to heat energy

IV. What are the two kinds of energy?

a.Kinetic Energy- energy in motion

1. Light, heat and sound energy

b. Potential Energy- stored energy

1. Chemical energy

V What is a simple machine?

• A machine with very few parts that helps people do work

VI. What is are six examples of simple machines?

1. Lever and fulcrum- a machine made from a bar or rod that turns on a point

a. helps by placing less effort to lift things (load)

2. Wheel and Axle- has a wheel connected to an axle

3. Inclined Plane- a machine made from a slanted surface

4. Pulley – a machine made from a grooved wheel and a rope or chain.

a. small effort needed to move things

a. small effort needed to move things

a. Easier to lift things

5. Screw – an inclined plane wrapped around a post.

6. Wedge – two inclined planes placed back to back

VII. What is friction and how does it affect a simple machine?

a. Friction is a force that slows down or stops motion

b. Friction makes it harder for a simple machine to work

c. Friction can be reduced by adding wheels or covering surfaces with oil or grease

VII. What is a compound machine?

a. A machine made from two or more simple machines.

1.Bike

• wheels connected to axle

• Pedals are a wheel & axle

• Handbrakes are a lever and fulcrum Edhead Game