1. Unit 2: A World of Energy 6th Grade Science
Fall 2005, Pflugerville ISD
© Fall 2005, Pflugerville ISD, 6th Grade

2. Unit 2: A World of Energy Chapter 5:Energy and Energy Resources
Section 1: What is Energy?
Section 2: Energy Conversions
Section 3: Using Energy
Section 4: Energy Resources
Fall 2005, Pflugerville ISD

3. What is Energy?
Chapter 5 Section 1
Fall 2005, Pflugerville ISD

4. What is energy? What is Energy? What Do You Think? Chapter 5 Section 1
Fall 2005, Pflugerville ISD

5. What is Energy? Energy is the ability to do work.
There are different kinds of energy:
Kinetic energy
Potential energy
Chapter 5 Section 1
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6. What is Energy? Kinetic energy is the energy of motion
All moving objects have kinetic energy
Kinetic energy depends on speed and mass
The faster something is moving, the more kinetic energy it has.
The more massive a moving object is, the more kinetic energy it has.
Chapter 5 Section 1
Fall 2005, Pflugerville ISD

7. What is Energy?
Potential energy is the energy an object has because of its position or shape.
Lifting an object gives it gravitational potential energy (GPE).
Gravitational potential energy (GPE) depends on weight and height.
Chapter 5 Section 1
Fall 2005, Pflugerville ISD

8. What is Energy? Energy comes in many forms: Thermal energy
Chemical energy
Electrical energy
Sound energy
Light energy
Nuclear energy
Chapter 5 Section 1
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9. What is Energy?
Thermal energy is the total energy of the particles that make up an object.
Because the particles are moving, they have kinetic energy.
At higher temperatures, the particles move faster
The faster particles move, the more kinetic energy they have and the greater the object’s thermal energy is
Thermal energy also depends on the number of particles in a substance.
Chapter 5 Section 1
Fall 2005, Pflugerville ISD

10. What is Energy?
Chemical energy is the energy stored in a substance that can be released when the substance reacts.
For example - when wood is burned, chemical energy is released.
Another example - when you eat something, your body is able to use the food’s chemical energy.
Chapter 5 Section 1
Fall 2005, Pflugerville ISD

11. What is Energy? Electrical energy is the energy of moving electrons.
When you plug in your alarm clock and turn it on, electrons in the wires move back and forth (120 times per second).
As the electrons move, energy is transferred to different parts of the clock to make it do work.
Chapter 5 Section 1
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12. What is Energy?
Sound energy is caused by an object’s vibrations.
When a guitar string vibrates, energy is transferred from the moving string to the air particles around it.
The particles transfer energy from one another and finally cause your eardrum to vibrate, and you hear the sound of the guitar.
Chapter 5 Section 1
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13. What is Energy?
Light energy is caused by the vibrations of electrically charged particles.
The vibrations that transmit light energy do not require particles to transmit energy.
Light energy, unlike sound energy, can be transmitted through a vacuum (like space).
Chapter 5 Section 1
Fall 2005, Pflugerville ISD

14. What is Energy?
Nuclear energy is caused by changes in the nucleus of an atom.
Nuclear energy is produced two ways:
When two or more nuclei join together (nuclear fusion)
When the nucleus of an atom splits apart (nuclear fission)
Chapter 5 Section 1
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15. What is Energy?
Websites to Visit:
Types of Energy Review- Click here to review the types of energy.
Chapter 5 Section 1
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16. What is Energy?
Activity
Make a simple drum. What do you hear? Change the way you hit the drum. What happens to the sound?
Quick Lab page 122- Hear that Energy.
See speaker notes for lab.
Chapter 5 Section 1
Fall 2005, Pflugerville ISD

17. Pre-AP Extension
Electric current is the flow of electrons form an object that has many electrons to another object that has too few electrons. Explore circuits with a battery, wires, light bulbs, and a voltmeter.
Introduction to Electric Circuits Lab from the LTF book page 733.
See speaker notes for lab.
Chapter 5 Section 1
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18. Let’s Review 1. What is Energy? Chapter 5 Section 1
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19. Energy is the ability to do work.
Answer
Energy is the ability to do work.
Chapter 5 Section 1
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20. 2. How are energy and work related?
Let’s Review
2. How are energy and work related?
Chapter 5 Section 1
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21. Answer
Energy is the ability to do work and work cannot be done without energy.
Chapter 5 Section 1
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22. 3. What are the different forms of energy?
Let’s Review
3. What are the different forms of energy?
Chapter 5 Section 1
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23. Answer Thermal Chemical Electrical Sound Light Nuclear
Chapter 5 Section 1
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24. Energy Conversions
Chapter 5 Section 2
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25. Energy Conversions
What Do You Think?
How is a moving pendulum converting potential energy to kinetic energy?
Chapter 5 Section 2
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26. Energy Conversions
An energy conversion is a change from one form of energy to another.
Any form of energy can be changed into any other form of energy. →
Chemical Energy
Kinetic Energy
Chapter 5 Section 2
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27. Energy Conversions
Mechanical energy is the sum of an object’s kinetic and potential energy.
Example:
When a pendulum is lifted, potential energy is stored.
When the pendulum swings, the potential energy is changed to kinetic energy.
The total energy is the pendulum’s mechanical energy.
Chapter 5 Section 2
Fall 2005, Pflugerville ISD

28. Energy Conversions
When you eat, the chemical energy of the food is converted by your body to other forms of energy.
Can you think of ways your body uses chemical energy?
Chapter 5 Section 2
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29. Energy Conversions
Activity
Take a close look at the energy conversion that occurs as a pendulum swings.
Energy of a Pendulum Lab page 610 in textbook.
Chapter 5 Section 2
Fall 2005, Pflugerville ISD
See speaker notes for lab.

30. Energy Conversions
Energy conversions also occurs in plants.
Plants use chlorophyll to convert light energy to chemical energy.
Chapter 5 Section 2
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31. Energy Conversions
Machines convert electrical energy into other forms of energy.
What types of energy does a hair dryer convert electrical energy into?
Chapter 5 Section 2
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32. Energy Conversions
The Law of Conservation of Energy states energy can neither be created nor destroyed.
The total amount of energy in a closed system is always the same.
Chapter 5 Section 2
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33. Energy Conversions
Friction is a force that opposes motion between two surfaces that are touching.
Some energy that appears to be “lost” actually becomes thermal energy due to friction.
Chapter 5 Section 2
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34. Energy Conversions
Energy efficiency compares the amount of energy before a conversion with the amount of useful energy after the conversion.
The less energy that must be used to overcome friction, the more efficient the energy conversion.
Chapter 5 Section 2
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35. Energy Conversions
What do we call cars that move through the air more easily and use less energy to overcome friction?
Chapter 5 Section 2
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36. Energy Conversions
A perpetual motion machine is a machine that runs forever without any added energy – 100% efficient.
Because all energy conversions result in some form of energy that isn’t useful, perpetual motion is impossible.
Chapter 5 Section 2
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37. Energy Conversion Website to Visit:
View some examples of energy conversions by clicking here.
Chapter 5 Section 2
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38. Energy Conversions
Activity
Design a protection system for an egg so you can drop it without it breaking thus the energy transfer will go into your protection system and not the shell.
Eggstremely Fragile Lab page 611 in textbook.
Chapter 5 Section 2
Fall 2005, Pflugerville ISD
See speaker notes for lab.

39. Pre-AP Extension
Explore the different forms of energy associated with different object and mechanisms and how they convert energy from one form to another.
Energy Conversion Lab from the Get Smart About Energy book produced by the US Department of Energy.
See speaker notes for lab.
Chapter 5 Section 2
Fall 2005, Pflugerville ISD

40. Let’s Review
1. Identify three energy transformations occurring during the production of energy for human use.
Chapter 5 Section 2
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41. Answer
Sample answer: A battery converts chemical energy into electrical energy.
Chapter 5 Section 2
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42. Let’s Review
2. Describe the energy conversions that take place when you ride in a car.
Chapter 5 Section 2
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43. Answer
Sample answer: The car converts the chemical energy from gasoline into thermal energy; which is then used to do work on the pistons. This gives the car kinetic energy.
Chapter 5 Section 2
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44. Using Energy
Chapter 5 Section 3
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45. How is energy transferred when you are riding a bike?
Using Energy
What Do You Think?
How is energy transferred when you are riding a bike?
Chapter 5 Section 3
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46. Using Energy
A machine is a device that can make work easier by changing the direction or size of force needed to do work.
Machines cannot transfer or change more energy than you transfer to them.
Chapter 5 Section 3
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47. Using Energy
When machines transfer energy, they can also convert energy.
Your alarm clock is an example: It transfers electrical energy to sound energy to help you wake up in the morning.
What are some other examples of machines causing energy conversions?
Chapter 5 Section 3
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48. Using Energy Heating systems move thermal energy to cooler areas.
Air or water is used to move thermal energy from burning fuel to other areas of a house or building.
Chapter 5 Section 3
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49. Using Energy
Solar heating systems convert light energy from the sun into thermal energy.
Active solar heating systems have moving parts – machines that move the sun’s energy throughout a building (such as pipes, fans, and storage tanks for water to be heated).
Passive solar heating systems do not have moving parts – they use thick walls and large windows that face south.
Chapter 5 Section 3
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50. Using Energy
Cooling systems move thermal energy out of the area that is to be cooled.
To move thermal energy from a cool area (indoors) to a warm area (outdoors), a cooling system must do work.
Chapter 5 Section 3
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51. Using Energy
Most cooling systems use electrical energy to do the work of cooling.
A machine called a compressor does the work of compressing a refrigerant.
A refrigerant is a gas that can easily change state to become liquid.
Chapter 5 Section 3
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52. Using Energy
Activity
Have a guest speaker come in such as an air conditioning expert to talk to the kids about refrigerators and heating systems.
Chapter 5 Section 3
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53. 1. What is the role of machines in energy transfer?
Let’s Review
1. What is the role of machines in energy transfer?
Chapter 5 Section 3
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54. Answer
Machines can transfer energy from one object to another as they make work easier.
Chapter 5 Section 3
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55. Let’s Review
2. Compare the hot-water heating system and an active solar heating system.
Chapter 5 Section 3
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56. Answer
Both systems use pumps to move heated water throughout the house. The thermal energy used to heat the water comes from burning fuel in a hot-water system and from the sun in an active solar heating system.
Chapter 5 Section 3
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57. Energy Resources
Chapter 5 Section 4
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58. What are some of the energy resources we use everyday?
What Do You Think?
What are some of the energy resources we use everyday?
Chapter 5 Section 4
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59. Energy Resources
An energy resource is a natural resource that people can turn into other forms of energy in order to do useful work.
Nonrenewable resources cannot be replaced after they are used or can only be replaced over thousands or millions of years.
Chapter 5 Section 4
Fall 2005, Pflugerville ISD

60. Energy Resources
Fossil Fuels such as coal, petroleum, and natural gas formed from the buried remains of plants and animals that lived millions of years ago.
The stored energy of these remains is released when the fossil fuels are burned.
Chapter 5 Section 4
Fall 2005, Pflugerville ISD

61. Energy Resources
Coal – most coal in the U.S. is burned in power plants to generate electrical energy.
Petroleum – gasoline, kerosene, wax, and other petrochemicals come from petroleum.
Natural Gas – the cleanest burning fossil fuel is used in heating systems, stoves and ovens, and a few vehicles.
Chapter 5 Section 4
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62. Electical Energy from Fossil Fuels
Energy Resources
Electical Energy from Fossil Fuels
The chemical energy of the fossil fuel is turned to thermal energy by burning.
Thermal energy is used to boil water and change it to steam.
Thermal energy is changed to mechanical energy as steam pushes against the blades of a turbine.
Chapter 5 Section 4
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63. Energy Resources
An electric generator changes mechanical energy into electrical energy.
The electrical energy can be sent to homes and businesses through electrical wires.
Chapter 5 Section 4
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64. Energy Resources
Nuclear power plants also generate thermal energy that boils water to produce steam.
Nuclear energy is generated from radioactive elements such as uranium.
In a nuclear power plant, a special process splits the nucleus of a uranium atom in two – giving off nuclear energy.
Chapter 5 Section 4
Fall 2005, Pflugerville ISD

65. Energy Resources
Renewable energy resources can be used and replaced in nature over a short period of time.
Solar Energy
Energy from water
Wind energy
Geothermal energy
Biomass
Chapter 5 Section 4
Fall 2005, Pflugerville ISD

66. Energy Resources
Solar Energy – sunlight can be changed into electrical energy by solar cells.
Energy from water – the potential energy of water in a reservoir can be changed into kinetic energy as the water flows downhill through a dam. The kinetic energy of the falling water turns turbines, which change it to electrical energy by turning a generator.
Wind Energy – the kinetic energy of wind can turn the blades of a windmill. A wind turbine changes the kinetic energy of the air into electrical energy by turning a generator.
Chapter 5 Section 4
Fall 2005, Pflugerville ISD

67. Energy Resources
Geothermal energy – Thermal energy caused by the heating of Earth’s crust is used by pumping water underground into areas of hot rock. The water returns to the surface as steam – which can then be used to turn a generator to change mechanical energy into electrical energy.
Chapter 5 Section 4
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68. Energy Resources Geothermal heating and cooling. Chapter 5 Section 4
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69. Energy Resources
Biomass – plants use an store energy from the sun. Organic matter that can be burned to release energy is called biomass. Some plants can be turned into liquid fuel - for example, corn can be used to make ethanol.
Cite:
Chapter 5 Section 4
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70. Energy Resources Facts:
100 tons of plant matter (the amount that exists in 40 acres of wheat)
Burning that gallon puts 20 lbs. of CO2 into the air.
The U.S. consumes 131 billion gallons of gas annually = 25 quadrillion lbs. of biomass = putting 26 trillion lbs. of CO2 into the air.
Since 1751, humans have burned the amount of fossil fuels that would have come from all the plants on Earth for 13,300 years.
Chapter 5 Section 4
Fall 2005, Pflugerville ISD

71. Pre-AP Extension
Nonrenewable resources will exhaust over time. Conservation is a way of using less energy along with the increase use of renewable resources. Explore the deletion of fossil fuel and the need to conserve and develop renewable resources.
Renew a Bean Lab from
See speaker notes for lab.
Chapter 5 Section 4
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72. 1. Describe fossil fuels and biomass from their source to their use.
Let’s Review
1. Describe fossil fuels and biomass from their source to their use.
Chapter 5 Section 4
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73. Answer
Fossil fuels are formed from the remains of plants and animals that lived millions of years ago, and biomass is organic matter that is obtained from things living today. Both are burned to released chemical energy, which can be converted into other forms of energy.
Chapter 5 Section 4
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74. Let’s Review
2. Determine whether the following energy types are renewable, nonrenewable, or inexhaustible:
Nuclear energy
Solar energy
Biomass
Chapter 5 Section 4
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75. Answer Nuclear energy is nonrenewable. Solar energy is inexhaustible.
Biomass is renewable.
Chapter 5 Section 4
Fall 2005, Pflugerville ISD