1. Chapter 3, Lesson 2, Energy Transfer

2. Chapter 3, Lesson 2, Energy Transfer Slide 1
*What is the main idea?
______________
-How do moving objects transfer energy?
*Energy can be transferred to one place to another
__________________________________________________
-A moving object can transfer energy from one place to another.
-For example, in bowling, a bowler transfers the kinetic energy of a bowling ball to the pins that the ball hits.
-The bowling ball carries energy from the bowler to the pins.

3. Chapter 3, Lesson 2, Energy Transfer Slide 2
Transferred
From
Bowler To
Pins

4. Chapter 3, Lesson 2, Energy Transfer Slide 3
*How does work transfer energy?
*Work is the transfer of energy that occurs when a push or pull makes an object move.
*In science, studying for a test is technically not considered work because there is no pushing or pulling involved.
*Work is done only when an object moves in the same direction as the force applied to it.
*Pushing on a brick wall is not work because the wall does not move.
*However picking up a box is because pulling the box is causing it to move.
*By doing work on the box, energy is transferred to the box.

5. Chapter 3, Lesson 2, Energy Transfer Slide 4
Is it considered work if you push against this wall?
Why?

6. Chapter 3, Lesson 2, Energy Transfer Slide 5
-How do waves transfer energy?
-A wave is a disturbance that transfers energy without transferring matter.
-In a wavy ocean, some of the energy carried by a water wave is transferred to you as the wave moves past you.
-The energy transferred by the wave causes you to move upward.
-Like moving objects, waves transfer energy from one place to another.

7. Chapter 3, Lesson 2, Energy Transfer Slide 6
*How do water waves transfer energy?
*A water wave transfers energy as it moves horizontally along the surface of the water.
*Like all waves, water waves transfer energy from one place to another, but they don’t transfer matter.

8. Chapter 3, Lesson 2, Energy Transfer Slide 7
-How do sound waves transfer energy?
-Energy can be transferred by waves that can’t be seen, such as sound waves.
-Sound waves are caused by the back-and-forth movement, or vibration, of an object.
-When a drummer hits a drum, the head of the drum moves back and forth many times each second.
-Each time the drum head moves, it hits nearby air particles and transfers kinetic energy to them.

9. Chapter 3, Lesson 2, Energy Transfer Slide 8
*What are electromagnetic waves?
*Electromagnetic waves are waves that can transfer energy through matter and empty space.
*Electromagnetic waves are light waves that carry radiant energy.
*Radiant energy moves from the Sun to Earth as electromagnetic waves.

10. Chapter 3, Lesson 2, Energy Transfer Slide 9
-Radio waves are used to carry signals you hear when you listen to the radio.
-Microwaves are electromagnetic waves that heat food in a microwave oven.
-Microwaves are also used to carry signals to cell phones.
-X rays are electromagnetic waves used to diagnose broken bones.
-What are types of electromagnetic waves?

11. Chapter 3, Lesson 2, Energy Transfer Slide 10
*What are energy conversions?
-How can potential energy be converted to kinetic energy?
*Energy comes in different forms and can be converted from one form to another.
-When you throw a ball upward, the ball’s kinetic energy turns into potential energy when it reaches its highest point.
-As the ball falls down, potential energy is converted back into kinetic energy.

12. Chapter 3, Lesson 2, Energy Transfer Slide 11
*How can chemical potential energy be converted?
*Fuel is a material that can be burned to release energy.
*Chemical potential energy is energy that is stored in the bonds between the atoms that make up wood.
*When wood burns it becomes fuel because it changes from chemical potential energy into thermal and light energy.

13. Chapter 3, Lesson 2, Energy Transfer Slide 12
-How can thermal energy be converted to kinetic energy?
-In a car, thermal energy from burning fuels can be used to perform work.
-The thermal energy produced by burning gasoline causes forces to be exerted on parts of a car’s engine
-These forces make various parts in the car’s engine to move making the car’s wheels move.

14. Chapter 3, Lesson 2, Energy Transfer Slide 13
*How can kinetic energy be converted to thermal energy?
*As a car moves, some of the kinetic energy is converted into thermal energy.
*The conversion of kinetic energy to thermal energy is due to friction of the moving parts in a car.
*Friction is the force that resists the sliding of two surfaces in contact.
*It is friction that causes a bicycle to stop when you apply the brakes.

15. Chapter 3, Lesson 2, Energy Transfer Slide 14
Friction

16. Chapter 3,Lesson 2, Energy Transfer Slide 15
-Summary
-Energy can be transferred in many different ways.
-Moving objects can transfer energy when they collide with other objects.
-Water waves, sound waves, and electromagnetic waves can also transfer energy as they move from place to place.
-Energy can can convert from one form to another.

17. Questions??? In science, is studying for a test considered to be work?
In science, is picking up a box considered work?
What kind of waves cannot be seen?
What is one type of electromagnetic wave?
How does a car convert chemical potential energy to kinetic energy?