1. What is Energy?

2. Definition Energy refers to the ability to cause change or do work.
Energy can be stored for later use (i.e. battery)
Or energy can be moving (i.e. vibration).

3. Energy causing change
When we say energy can cause change or do work we usually refer to things like:
Changing temperature by heating or cooling something.
Or changing state (liquid/solid/gas).
The texture and atomic structure of cookies actually changes when you increase their temperature. Energy in the form of heat is needed to make this change occur.

4. Energy causing change
When we say energy can cause change or do work we usually refer to things like:
Changing volume. For example, blowing up a balloon. Or crushing a piece of paper.
You are out of breath after blowing up a balloon because you are actually using energy to increase the volume of the balloon.

5. Energy causing change
When we say energy can cause change or do work we usually refer to things like:
Building or destroying something. For example, demolishing a building.
It takes energy to destroy something because you are changing its structure.

6. Energy causing change
When we say energy can cause change we usually refer to things like:
Making something move or stop moving something that is already moving.
It takes energy to speed up a vehicle and energy to stop it. It also takes energy to make the vehicle turn. In each of these example the motion of the vehicle is changing. Most vehicles get their energy from gasoline or some other kind of fuel.

7. You also need energy
When you’re born, you are pretty small. You need energy to grow. Your structure is changing.
You need energy to make yourself move.
And inevitably you get hurt or your cells wear out so you need energy to heal or grow new cells.
You get all this energy from your food.

8. Energy Causing Change
Basically, if something won’t happen by itself, you need energy to make it happen.

9. Units
To measure how much energy we have, we usually use the following units:
Joules – this is the metric unit for energy.
Calories – you may be more familiar with this unit of energy from your food.
Kilowatt-hours – this is the unit the electric company uses to determine how much you owe them every month.