1. Question of the Day Rules
You must work alone
You may use your textbook today
You have 6 minutes to complete the QOD
Good luck!!

2. Questions of the Day
1) Is it more energy-efficient to let a lightbulb burn for a short period of time, or to turn it off and then on again?
2) Sani bought a new camel and wants to know the energy efficiency. The camel consumes 350 Joules of energy, but only does 50 Joules of work (lazy). What is the energy efficiency of the camel?

3. Answers .
1) Is it more energy-efficient to let a lightbulb burn for a short period of time, or to turn it off and then on again?
Answer: It is more energy efficient to turn the light off than to leave it on. Energy is measured with respect to time. The momentary or millisecond or less surge of electricity required to start your light bulb will not impact your energy cost, but leaving it on all the time will.

4. Answers
2) Mr. Meades bought a new camel and wants to know the energy efficiency. The camel consumes 350 Joules of energy, but only does 50 Joules of work. What is the energy efficiency of the camel?

5. What are we doing Today?
Hand in lab on ppm
Question(s) of the day
Ch. 3 – notes
Get back ICEPAC
Workbook p.39-40
Horse Race

6. • Energy is the ability to do work or effect change (p. 71).

7. • Energy transfer is the movement of energy from one place to another (p. 71).

8. Energy Transfer
Examples:
Roasting marshmallows with a wire. Conduction transfers energy as heat along the wire and into the hand.

9. Energy transformation is the changing of energy from one form to another (p. 71).

10. Energy Transformation
Examples: 1) A lightbulb, where electrical energy is transformed into light energy

11. The law of conservation of energy: says that energy is neither created nor destroyed. When we use energy, it doesn’t disappear. We change it from one form of energy into another.

12. Energy Efficiency
Energy Efficiency is the amount of useful energy you get from a system.
Converting one form of energy into another form always involves a loss of usable energy.

13. Example of Energy Efficiency
In fact, most energy transformations are not very efficient. The human body is a good example. Your body is like a machine, and the fuel for your machine is food. Food gives you the energy to move, breathe, and think. But your body isn’t very efficient at converting food into useful work. Your body is less than five percent efficient most of the time. The rest of the energy is lost as heat. You can really feel that heat when you exercise!

14. Energy Efficiency

15. Energy Efficiency Question
To perform work equal to 2 400 J, a machine consumes 12 000 J. What is the energy efficiency of this machine?

16. To perform work equal to 2 400 J, a machine consumes 12 000 J
To perform work equal to 2 400 J, a machine consumes 12 000 J. What is the energy efficiency of this machine?

17. Thermal energy is the energy contained in a substance, determined by the number of particles in the substance and their temperature (p. 73).

18. Thermal energy is the energy contained in a substance, determined by the number of particles in the substance and their temperature (p. 73).

19. Heat: is the transfer of thermal energy between two environments with different temperatures. Heat always passes from the warmer to the cooler environment (p. 73).

20. Question ?
If a cup of coffee and a red popsicle were left on the table in this room what would happen to them? Why?
The cup of coffee will cool until it reaches room temperature. The popsicle will melt and then the liquid will warm to room temperature.

21. • Temperature: is a measure of the degree of agitation of the particles of a substance (p. 74).

22. Chemical Energy
Stored chemical energy is released in the form of thermal energy when it is burned.

23. Electrical Energy Electricity
Example: hydro-electric dams – falling water is changed to electrical energy

24. Geothermal Energy
Energy that we get from the Earth’s interior

25. Solar Energy
Energy from the sun

26. Wind Energy
Moving air
Is a result of solar energy – as the sun heats the air, the warmer air rises and cools off. Cooler air falls, creating a convection current – this forms wind

27. Fossil Fuels
Chemicals made from plants and animals that died and decomposed millions of years ago and have preserved deep underground.

28. Complete P.39-40 in your workbook. Begin Now!
ClassWork
Complete P in your workbook.
Begin Now!