1. ENERGY
Grade 8
J. Kelly
rgy/preview.weml

2. Money vs. Energy... You can have different sources or stores of money.
Stored as cash in your pockets
Stored as money in your bank account
Stored as shares in a company’s stock
You can have different sources or stores of energy.
Stored in the chemicals of a firework
Stored in a stretched rubber band
Stored is an object held up high

3. Money vs. energy Money Energy
The amount of money in the store sets a limit on what you can buy.
With a little money, you could buy a hot chocolate at Tim Hortons, a ride on the city bus etc.
With a lot of money, you could buy a steak at Baton Rouge, a ride on an air plane, or a Mercedes
The more money stored in your pocket, the greater the potential you have to buy things.
The amount of energy in the store sets a limit on what can happen.
With a little energy, you could warm a small beaker of water, light a room, or drive your car to school.
With a lot of energy, you could boil a bath full of water, floodlight a football stadium, or fly to China.
The more energy stored in an energy source, the greater the potential it has to do things.

4. Money vs. Energy
Money
Energy
When you buy something, money is transferred from one store to another.
When you buy a burger, money is transferred from your pocket to the cash register at McDonald’s
If you don’t buy anything, the money stays in your pocket
When something happens, energy is transferred from one store to another.
When a firework blows up, energy is transferred from the chemicals to the surroundings by light waves and by heating.
If the firework doesn’t blow up, then the energy stays stored in the chemicals.

5. Money vs. Energy Money Energy Money is used as an accounting system.
When buying things, it is useful to track the transfers of money to account where it ends up.
This is a mathematical process with the amount of money being measured in Dollars ($) and no money is lost but just transferred to other stores.
Energy is used as an accounting system.
When things happen, it is useful to track the transfers of energy to account where it ends up.
This is a mathematical process with the amount of energy being measured in Joules (J) and no energy is lost but just transferred to other stores.

6. What is energy?
Energy makes change possible. We use it to do things for us. It moves cars along the road and boats over the water. It bakes a cake in the oven and keeps ice frozen in the freezer. It plays our favorite songs on the radio and lights our homes. Energy is needed for our bodies to grow and it allows our minds to think.

7. Definition of energy
Energy is the ability to do work or effect change\
Energy is in everything. We use energy for everything we do, from making a jump shot to baking cookies to sending astronauts into space.

8. Forms of Energy Form of energy Description Examples of sources
Elastic energy
Energy stored in an object due to its compression or extension
Compressed spring
Stretched elastic
Electrical energy
Energy from the ordered movement of electrons from one atom to another
Power plant
battery
Thermal energy
Energy from the random motion of all particles in a substance
Fire, sun, element
Radiation energy
Energy contained in a transported by electromagnetic waves
Light bulb, microwave, sun, cell
Chemical energy
Energy stores in molecular bonds
Apple, candle wax, fossil fuels
Wind energy
Energy resulting from the movement of air
wind
Sound energy
Energy contained and transported by sound waves
Sound, music
Hydraulic energy
Energy resulting from the flow of water
Waterfall, river
Nuclear energy
Energy stored in atomic nucleii
Sun, atomic nucleii

9. The Law of conservation of energy
Energy can also change from one form to another
Energy Transformation: The changing of energy from one form to another

10. Example of Energy transfer and transformation

11. Energy Efficiency
Humans build and use machines that are capable of transforming energy from one form to another.
But... A machine can rarely convert all the energy it consumes into a useful form.
The rest is changed into another form or dispersed into the environment
Ex: In an incandescent light bulb only 5% of the electrical energy consumed is actually used to produce light