1. Chapter 4: ENERGY
Section 1

2. The Nature of Energy

3. What is Energy? Energy is the ability to cause change.
Every change that occurs requires energy.

4. Energy Has Different Forms
Some forms of energy
Electrical
Chemical
Radiant
Thermal

5. Forms of Energy
Some things can have more than one type of energy at a time.
Energy can convert from one form to another.
Energy can be stored in
many ways.

6. Electrical Energy Electric circuit

7. Chemical Energy Chemical change animation
How MRE heaters work

9. Radiant Energy

10. More Radiant Energy Examples

11. Thermal Energy

12. Other Forms of Energy. . . There are also these types of energy:
Kinetic energy is the energy of a moving object.
Potential energy comes in 3 different forms:
Gravitational potential is stored energy due to an object’s position.
Elastic potential energy stored by something that can stretch, compress, or bend—like a rubber band, spring, or pole vault.
Chemical potential energy is the energy stored in chemical bonds.

13. Kinetic Energy Kinetic energy is measured in joules
Use the formula KE=1/2 mass x velocity2
In other words: 1/2mv2

14. Gravitational Potential Energy
Watch out for falling rocks and cows!

15. Converting GPE to Kinetic Energy
As an object falls, its potential energy is converted into kinetic (moving) energy.
As the object approaches the ground, it will have the greatest kinetic energy—and the least potential energy.
The gravitation potential energy (GPE) can be calculated using this formula:
Mass (kg) x acceleration due to gravity (m/s2) x height of object (m)
In other words:
kg x m/s2 x m = GPE
or mgh = GPE

16. Elastic Potential Energy
Watch this:
And these:

17. Chemical Potential Energy
Watch this:
And this:

18. Section 2: Conservation of Energy

19. Electrical Energy Electrical energy can be transformed into
Thermal energy
Radiant energy
Mechanical energy
Sound Energy

20. Chemical Energy Transformed into Radiant energy Sound GPE
Kinetic/mechanical energy
Thermal energy
Car Engine Animation

21. Kinetic to Potential Energy
Pendulum swinging is a good example.

22. More Potential to Kinetic
Mechanical energy is the total amount of potential and kinetic energy in a system.
Formula: ME = PE + KE
What happens to the mechanical energy of the apple as it falls?
Potential energy decreases; kinetic energy increases; total mechanical energy remains the same.

23. Projectile Motion
Conversions from kinetic to potential and back to kinetic are taking place.

24. Energy Transformations in a Swing
Another good example of kinetic to potential energy transformations.

25. Law of Conservation of Energy
Energy cannot be created or destroyed, it simply changes form.
Matter can be converted into energy through
Fusion—atomic nuclei fusing together
Fission—atomic nuclei being broken apart

26. Fission vs Fusion

27. Fusion

28. Fission

29. More on the LAW of Conservation of Energy
It may seem as though energy is being lost, as with the pendulum example, but some energy is generally lost to FRICTION.
Friction creates thermal energy.
Air resistance (another type of friction) slows things down.
GRAVITY is also a factor in stopping motion.

30. Conserving energy is not the same as “Conservation of Energy”
To conserve energy means to not waste energy resources.
On the other hand, the law of conservation of energy is a universal principal that describes what happens to energy as it is transferred from one object to another or one form to another.

31. Your Body’s Use of Energy
Your body stores energy from the foods you eat in the form of fat and other chemicals.
When your body needs that energy, it will “burn” the fat. In other words, the chemical energy from fat will convert into thermal and mechanical (kinetic) energy.

32. How Do We Measure Energy in Food?
The label used for a unit of food energy is the Calorie (note it is capitalized).
1 C is equal to about 4,184 Joules.
A gram of fat consumed contains about 9 C.
A gram of carbohydrates or proteins contain about 4 C of energy.
Carbs include sugars, starches, and fiber
Fat contains the most energy of all foods.