1. Energy Efficiency

2. Energy Efficiency is …
The measure of the ratio of output energy to input energy.

3. Unwanted energy / lost energy
When energy transforms, some energy is turned into useful energy, but some energy is always transformed into an unintended form.
The unintended energy = unwanted energy, or energy lost to the environment.

4. Heat from your phone? Examples: When you use your phone; it gets hot.
It’s using energy from the battery.
Even though you don’t want it to get hot:
it is UNWANTED energy.

5. Clothes dryer– makes noise! Light bulbs – get hot!
How efficient are the following items? Do they do their job 100%, or is there some energy lost?
Clothes dryer– makes noise!
Light bulbs – get hot!
Can you think of any other examples?

6. Calculating Energy efficiency
Input
Output
Efficiency
60 joules
45 joules
3,000 joules
1,300 joules
400 joules
50 joules

7. Where does our energy come from?
Title / names /pictures
Explanation of energy source (where does it come from? How does it generate electricity for our homes?
Pros and Cons
Energy efficiency – output energy vs. input energy

8. What are the efficiencies of the following