1. Energy: Introduction

2. 1. Energy can be said to be based on all of the following except:
How far an object moves.
How much force is applied to an object.
How many seconds a force is applied for.
How fast an object is moving.

3. Energy is based on motion.
An object moving
Active energy
An object that has the potential to be moving
Stored energy

4. Energy of Motion – Kinetic Energy
Motion of objects larger than molecules
Typically motion of objects we can see with the naked eye

5. Kinetic Energy
Get used to the equation:
𝐾𝐸= 1 2 𝑚 𝑣 2

6. Potential for Motion – Gravitational Potential Kinetic Energy
A macroscopic object could move faster because gravity is pulling on it.

7. Gravitational Potential Energy
Get used to the equation:
𝐺𝑃𝐸=𝑚 𝑎 𝐺 ℎ

8. Potential for Motion – Elastic Potential Kinetic Energy
An object could move faster because there is either attraction or repulsion acting on it.

9. Elastic Potential Energy
Get used to the equation:
𝐸𝑃𝐸= 1 2 𝑘 𝑠
Where k is a “springiness” constant… more on that later.

10. How is energy given to an object?
How do we get objects to move?
Apply a force!
If we apply a force but nothing moves, did we give it energy?
Not only must a force be applied, but it must move the object.
NO NO NO

11. Work Doing work to an object gives it energy.
Work is defined in physics to be “effort”
How measure “effort”
𝑊 = 𝐹 𝑑
Work equals the product of force applied and the distance over which it was applied.

12. How to show transfers of Energy
LOL Diagrams
How to show transfers of Energy

13. The LOL Original Objects Final go here Drawn as:
Bar graph (for original case)
Circle (for energy transfers)
Bar graph (for final case)
Describes energy transformations over a given time period, between objects.
Objects
go here
Original
Final

14. Ex: an object falls from up high.
System: box and earth.
A box falls from the side of a table.
Original case: box on edge of table.
Final case: box about to hit ground.
Earth’s Gravity
BOX

15. Acquire LOL Practice

16. What is it? How is it created?
Thermal Energy
What is it?
How is it created?

17. Energy of Motion – Thermal Energy
The average motion of all the particles in an object
Particle means atoms and/or molecules and/or proton/neutrons in this case

18. Friction can generate T.E.
Rub table until warm.
Rub table until HOT.
Difference?
What’s happening at the atomic level?

19. Energy Leaving the System
How to diagram it with an LOL.

20. Ex: Rubbing the table. System: your hand.
You rub the table with your hand as hard as you can.
Original case: rubbing begins.
Final case: rubbing done, hand warm.
HAND
T.E. to table.

21. Acquire LOL Practice

22. Chemical and Light Energy
Energy from Atoms

23. Potential – Chemical Energy
Energy is trapped in the chemical bonds between atoms in a molecule.
Most molecules, when given a little push to break apart, separate and move very quickly.
What is that fast atomic motion known as?

24. Transfer of Energy – Light Energy
Light is the succession of a magnetic field and electric field. Each one creates another field a little further out
Known as electromagnetic radiation for a reason!
Light comes from the motion of electrons, creating an electric field

25. Transfer of Energy – Light Energy cont.
What was thermal energy again?
Atoms moving around
When an atom moves, so does its electrons
Recall: moving electrons create light

26. Transfer of Energy – Light Energy cont.
It is a transfer of energy because light is not made of matter
Light is like potential energy because it can make things (like electrons) move
Light is like kinetic energy because it itself, moves
It’s moving potential energy… so it’s a bit of both

27. (4 min) To your partners:
Where does light come from?
What can it move?
Why is it like both Kinetic and Potential Energy?