1. Bell Ringer Read pages 588-589 with your shoulder partner.
Where does the term energy come from? Site evidence from the text.
Your book identifies chemical and nuclear energy. What are some other forms of energy?
How does energy transform to make water on the stove boil

2. Energy

3. Section 1
Energy Changes

4. What is Energy?
You may think that a bowl of spaghetti gives you energy, but do you realize that a burning fire, a bouncing ball, and a tank of gas are also energy?
The word energy comes from the Greek word energos which means “active”
Energy is the ability to cause a change
Energy can change the temperature of a pot of water, produce lightning in a storm, or rattle windows with thunder

5. Forms of Energy What do you think of when you think about energy?
Energy comes in a variety of forms and from a variety of sources
Food provides energy in the form of chemical energy
Nuclear power plants use nuclear energy contained in atoms to produce electricity
What are some other forms of energy

6. Energy Transformations
Energy is stored in the chemical compounds in your body
When you push down on your bike pedals, chemical energy makes your muscles move
Energy transformations occur when energy changes from one form to another
Chemical energy makes your muscles move, the sun’s energy transforms into heat energy that warms the inside of a car
Energy is never destroyed, it simply changes into a different form

7. Using Energy Transformations
Since the earliest times, humans have used energy transformations
Early humans used the chemical energy in wood to create fires to cook, stay warm, and light their way
Today, a gas stove uses chemical energy in natural gas to boil water and cook food
Electrical energy transforms to heat energy to power you hair dryer

8. Bell Ringer Read pages 590-591 with your shoulder partner.
What is kinetic energy?
What determines the amount of kinetic energy an object has? Give an example from the text.
What is an energy transformation?
How do humans use energy transformations?

9. Kinetic Energy
One soccer ball sits still on the ground, the other is moving.
How does the energy of the moving ball compare to the still ball? Discuss with your partner.
The moving ball has the ability to create change (a bowling ball knocking over pins)
The energy an object has due to its movement is called kinetic energy

10. Mass, Speed, and Kinetic Energy
Although all moving objects have kinetic energy, not all moving objects have the same amount of energy
What do you think determines the amount of energy?
The amount of energy an object has depends on its mass and speed

11. Mass, Speed, and Kinetic Energy
Think about a small pebble and a large boulder rolling downhill at the same speed
Which has more energy?
Think about the damage the two will cause when they hit something
The boulder has more mass, so it will cause more damage and has more kinetic energy
Kinetic energy also depends on speed, the faster the object is moving, the more kinetic energy it has.

12. Transferring Kinetic Energy
Kinetic Energy can be transferred from one object to another when they collide
Think about the transfer of energy when bowling.
Even though the ball does not touch all the pins, it can still knock down all the pins through a transfer of energy
The ball transfers all of its energy to a few pins that knock down other pins
Falling dominoes work the same way!

13. Potential Energy
Suppose you take a ski lift to the top of hill (pg. 592, fig. 7)
The skier at the top of the hill has no kinetic energy when she is standing still
As she skis downhill and moves faster, her kinetic energy increases
Where did the kinetic energy come from?
Gravity pulls her downhill and forces her to speed up.
If she were standing at the bottom of the hill, she would not be pulled downhill by gravity

14. Potential Energy
The skier has a form of energy at the top of the hill called potential energy.
Potential energy is the energy that is stored because of an objects position
By using the ski lift, the skier increased her potential energy by changing her position

15. Bell Ringer Read pages 593-594 with your shoulder partner.
How can you increase the amount of potential energy an object has?
What happens to the potential energy in a skier when they go down hill?
What kind of energy does a baseball have at its highest point when you throw it into the air?
How do you know, site evidence from the text.

16. Increasing Potential Energy
When you raise an object above its original position, it has potential to fall, therefore it has potential energy
The ski lift uses energy when it takes the skier to the top of the hill and some of that energy is transferred to the skier in the form of potential energy
As the skier goes downhill, the potential energy is transferred into kinetic energy
If the skier were lifted higher, she would have more potential energy

17. Converting Potential and Kinetic Energy
When you throw a ball into the air potential energy is transferred into kinetic energy
As the ball gets higher, it is storing up potential energy
When the ball reaches its highest point, it stops for an instant before it starts to fall
At this point the ball has no kinetic energy and is full of potential energy
As the ball falls back to your hand, the potential energy is converted into kinetic energy

18. Energy Changes in Water
Just like the ball falling to the ground, water has kinetic energy
That kinetic energy can be used to create electricity
Water is held behind a dam creating a lake or reservoir
Water near the top falls downward spinning a generator which produces energy
The potential energy of the water behind the dam is converted to electrical energy

19. Conserving Energy
Following the trail of energy can sometimes be difficult, it may seem as though energy is lost or destroyed
However, in 1840, James Joules demonstrated the Law of Conservation of Energy – energy can neither be created nor destroyed
The total amount of energy in the universe can never change, it can only change form
Kinetic energy can be transformed into heat energy through friction

20. Following the Energy Trail
Imagine the flow of energy in a soccer ball
Chemical energy is converted to kinetic energy when the soccer player kicks the ball
When the ball is kicked, kinetic energy is transferred to the ball
After a while, the ball rolls to a stop.
Is seems as though the kinetic energy in the ball disappeared! Where did it go?
As the ball rolled, its kinetic energy was transferred to the grass through friction

21. Bell Ringer Read pages 596-597 with your shoulder partner.
Think back to our previous lesson on the states of matter, what are the three main states of matter?
Which state has the most room for the atoms to move?
How do atoms in a solid move?
Why do scientists not use the terms hot and cold? Where did you find your answer to this question?
What is temperature?

22. Temperature
Section 2

23. Temperature
What is the temperature today? Is it hot or cold outside, do you need a jacket?
Hot and cold are everyday terms used to describe temperature, but those terms are not scientific.
While you may think it is cold in the classroom, someone else may think it is comfortable or even too hot!

24. Temperature and Kinetic Energy
Remember that everything is made of atoms which are in constant motion, even when they appear to be still
Even objects such as your desk and your pencil, which seem to be still, have atoms that are moving around at all times
Those atoms do not move in one direction, but tend to bounce around
The atoms in gases can bounce around more than the atoms in a liquid
The atoms in solids just kind of move back and forth

25. Temperature and Kinetic Energy
Temperature is the measurement of the average kinetic energy of the atoms in an object
When an objects temperature is higher, it has more kinetic energy
As temperature increases, the objects atoms move faster, which means they have more kinetic energy.

26. Measuring Temperature
Some people may say the temperature of the water in a swimming pool is cold, while others say it is warm
This is why temperature can’t be accurately described by how it feels
Since temperature is the measure of how much energy the atoms of an object has, you may think you need to measure the atoms themselves

27. Measuring Temperature
However, atoms are so small that even a tiny piece of material has trillions of atoms in it
There is no practical way to measure the energy of an atom
So what is a scientist to do?
One practical way of measuring temperature is to use a thermometer

28. Bell Ringer
Read pages starting at The Fahrenheit Scale with your shoulder partner.
What is temperature and how is it measured?
What are the two scales used to measure temperature on a thermometer
Why does your hand get cold when you pick up a glass of iced tea? You must talk about energy transfer in your answer.
What is heat?

29. The Fahrenheit Scale
The temperature scale you should be most familiar with is the Fahrenheit scale.
On the Fahrenheit scale, the freezing point of water is 32◦F and the boiling point of water is 212◦F
The space between the freezing point and boiling point is evenly divided between into 180◦
This scale is mainly used in the USA.

30. The Celsius Scale
Another temperature scale that is more widely used is the Celsius scale
On the Celsius scale, the freezing point of water is 0◦F and the boiling point of water is 100◦F
Because there are fewer degrees between those points on the Celsius scale, the temperature change between degrees is greater on the Celsius scale than on the Fahrenheit scale.

31. Heat
On a warm day, you can feel the suns heat on you, in the winter, you can feel the heat of a fire on your cold hands
In both cases, you could feel the heat making you warmer
If you pick up a glass of iced tea and hold it, the drink will warm up while your hand gets colder
This because your hand has more kinetic energy

32. Heat
Kinetic energy from your hand is transferred to the drink when the atoms in your hand collide with the atoms in your drink
A transfer of energy from one object to another due to a difference in temperature is called heat
Heat flows from warmer object to cooler ones
The heat from your hand will continue to flow into the drink until your hand and the drink are the same temperature

33. Heat and Temperature
How much does the temperature of an object increase when heat is transferred to it?
It depends on the object
The more mass the object has, usually, the more heat it will take to raise its temperature
Water is strange though, it takes an unusual amount of heat to raise the temperature of water one degree
For this reason, water is often used as a coolant in cars

34. Bell Ringer Read pages 600-601 with your shoulder partner.
How does a lake’s temperature change in relation to the city near it?
What is conduction, conductors, and insulators?
Give an example of conduction.
Give two examples each of conductors and insulators from the text.

35. Lakes and Air Temperature
How does the temperature of a lake compare to the temperature of the surrounding air on a hot summer day?
If you have been swimming in a lake, you may have noticed that the water seems cooler than the air.
Remember that water absorbs lots of energy before it begins to heat up
Therefore large bodies of water heat up and cool down slower than the surrounding air
Therefore, a lake will be cooler in the summer, and warmer in the winter!

36. Heat on the Move
A transfer of energy occurs if there is a difference in temperature between two object on contact
The can happen in three ways: radiation, conduction, and convection
Conduction transfers heat through solids and liquids
Convection transfers heat through liquids and gases
Radiation transfers heat through space

37. Conductors
Materials that make it easy to transfer energy are called thermal conductors
Most metals are good conductors of heat
Metals such as gold, silver, and copper are the best conductors
Copper is widely available and often used in cooking pans.
While much of the pan may be made of steel, they sometimes have a copper bottom because copper spreads heat more evenly

38. Insulators
Materials that do not transfer heat well are called thermal insulators
When you are cold, you may put on a sweater, you do this hoping to stay warm by adding insulation
They make it harder for heat to escape and hold the warm air around your body in place
Insulators contain many air spaces that trap air, which a good insulator.
Other example of insulators are plastic, wood, rubber, and ceramics (floor tiles)

39. Bell Ringer Read pages 602-603 with your shoulder partner.
What is convection and radiation?
Site an example of each from the text.
Popcorn can be cooked in a pan on the stove, by a hot air popper, and in the microwave. Which method is conduction, which is convection, and which is radiation?

40. Feeling the Heat
On a hot summer day, would you rather sit on a seat made of fabric or vinyl that has been in the sun all day
While both have been in the sun the same amount of time and the air around them is the same temperature, the vinyl seat feels hotter
This is because the vinyl transfers heat faster than fabric
The seat feels hotter because it transfers its energy to your skin much faster than the fabric seat

41. Convection
Convection is the transfer of energy between objects or areas that differ in temperature
This is most common in liquids and gasses
As temperature increases, particles move around more quickly, this cause density to decrease
Cooler denser materials cause warmer, less dense material upward
See figure 19 on page 602 to see how your house can be heated through convection!

42. Examples of Convection
Eagles and hawks seem to float along effortlessly high in the sky
Sometimes birds can stay in the air without flapping its wings!
In this case, the bird is held in the sky by a thermal – a column of warm air forced upward as the cool air around it sinks
This is also known as a convection current
This can also happen in water and is why oceans have water currents

43. Radiation Radiation is the transfer of energy through waves
These waves can be visible light, or other types of waves you can’t see
When these waves strike an object, it can transfer its energy to the object causing its temperature to rise
This is how the Sun transfers its energy to the Earth
A microwave cooks food by using microwave radiation to transfer energy to the food

44. Bell Ringer Read pages 604-605 by yourself.
What is a chemical reaction?
What is the potential energy stored in chemical bonds called?.
Name two examples from the text where chemical energy is stored.
What is required to break chemical bonds?

45. Bell Ringer
Name one source of chemical energy that helped you get to school today.
What is the freezing point of water in Fahrenheit and Celsius?
What kind of current is created when warm air rises and cold air sinks?

46. Chemical Reactions and Energy
Have you ever seen fireflies glowing at night, or perhaps a glow stick?
Ever wonder what causes them to glow?
Energy in the form of light is released when a chemical reaction takes place inside the glow stick
Everyday, you take advantage of the energy released by many chemical reactions

47. What is a Chemical Reaction
In a chemical reaction, compounds are broken down or new compounds are formed
Some chemical reactions occur when atoms or molecules come together
New compounds are formed when atoms and molecules come together and bonds are formed between them
Compounds are broken down when the bonds between them are broken and those atoms become free to form new compounds

48. What is a Chemical Reaction
When a fire burns, bonds between the atoms that make up the wood are broken
These atoms then combine with atoms in the air to form new compounds
As these new compounds are formed, light and heat are given off

49. Chemical Bonds
Energy is stored in the bonds between the atoms in a compound
The energy stored is potential energy in the form of chemical energy
Chemical energy stored in the bonds of oil, gas, and coal are important sources of energy
The chemical energy stored in food are important sources of energy for your body
Your body transforms chemical energy into kinetic energy when your muscles move

50. Energy in Reactions
In every chemical reaction, transformation in energy occur
To break bonds, energy must be added, to create those bonds, energy must be released
For example, when a lit match is placed in a mixture of hydrogen and oxygen gas, an explosion occurs
Energy stored between the bonds of the hydrogen and oxygen gas is released
Water is formed when bonds are reformed between the hydrogen and oxygen

51. Bell Ringer Read pages 606-607 by yourself.
What is an endothermic reaction?
Give an example on an endothermic reaction.
What is an exothermic reaction?
Give an example on an exothermic reaction.
Do all chemical reactions take place at the same rate, how do you know?

52. Energy Absorbing Reactions
Some chemical reactions need a constant supply of energy to keep them going
Chemical reactions that absorb heat energy are called endothermic reactions
Cooking food is an example on an endothermic reaction
The food absorbs thermal energy as is cooks, when the food is removed from the heat, it stops the cooking process

53. Energy Absorbing Reactions
Chemical reactions occur when sunlight strikes the leaves of plants
These reactions convert the energy contained in the sunlight to chemical energy contained in a type of sugar
Oxygen is also produced in this reaction called photosynthesis
When a plant is deprived of sunlight, this process stops
Photosynthesis is probably the most important chemical reaction on the planet since it provides all other living things with oxygen

54. Energy Releasing Reactions
Endothermic reactions are usually important because of the compounds they release
Other reactions are important because they release energy
Exothermic reactions are reactions that release energy
When a substance burns, it combines with oxygen atoms in the air and energy is given off in the form of heat and light

55. Energy Releasing Reactions
An exothermic reaction that occurs when a material burns by combining with oxygen is called combustion
Burning oil, coal, and gas produces much of the energy we need to heat homes and schools

56. Rate of Reaction Chemical reactions can occur at different rates
They occur very fast in the case of fireworks, however if you leave metal outside for a long time, it will slowly begin to rust
Rusting is chemical reaction between metal and oxygen and occurs much slower than a fireworks explosion
An enormous amount of chemical reactions are occurring in your body every second
The rate of these reactions are carefully controlled by your body

57. Bell Ringer Read page 608 by yourself.
What are two ways to change the rate of a chemical reaction?
What is a catalyst?
How do catalysts assist you in chewing your food?
Give two other examples of reactions that are assisted by catalyst?

58. Changing the Rate of Reactions
Two ways to change the rate of reactions are by changing the temperature and by adding a compound called a catalyst
If you pour cake batter into a pan and leave it on the counter for several hours, nothing will happen
However, if you put that pan in the oven, the batter will become cake
Raising the temperature of the cake in the oven caused the substances in the batter to react more quickly

59. Energy Releasing Reactions
A catalyst is a substance that changes the rate of a chemical reaction without any change to its own structure
Many cell processes in your body are controlled by the presence of catalysts called enzymes
Enzymes are found throughout your body and are important for growth, respiration, and digestion
When you chew your food, an enzyme called saliva is released into your mouth

60. Energy Releasing Reactions
Saliva helps break down starches in food into smaller molecules
Many other chemical reactions also depend on catalysts
The production of vegetable shortening, synthetic rubber, and high-octane gasoline are chemical processes that occur with the help of catalysts