1. What is Energy?
Ch. 5---Section 1

2. Energy The ability to cause change Can take many different forms
Kinetic - moving
Potential - positional
Thermal – Increases with heat
Chemical – stored in bonds
Radiant – light
Sound – vibration of molecules
Electrical – from electricity
Nuclear – stored in atoms
SI unit is the joule (J)
Energy and work are related
Energy is the ability to do work and work is the transfer of energy, therefore they are measured the same way!

3. Kinetic Energy (KE) The energy an object has due to its motion
If an object isn’t moving it doesn’t have any KE
Depends on both the mass and velocity of an object:
If two objects have the same mass, the one travelling with greater velocity has more KE
If two objects are travelling the same velocity, the object with greater mass has more KE

4. Gravitational Potential Energy (GPE)
The energy an object has due to its position
If an object isn’t moving, it can still have GPE
Depends on both the mass of the object and it’s height above the ground:
If two objects have the same mass, the one that is higher up has more GPE
If two objects are positioned at the same height, the object with greater mass has more GPE
KE and GPE are collectively referred to as Mechanical Energy

5. Potential Vs. Kinetic Energy
Law of conservation of energy - energy cannot be created or destroyed. 1.
Potential energy = 50 J
Kinetic energy = 0 J 2.
Potential energy = 25 J
Kinetic energy = 25 J 3.
Potential energy = 0 J
Kinetic energy = 50 J

6. Thermal Energy
The energy that all objects have that increases when the object’s temperature increases
Due to the motion of molecules that make up the object
Ex. A cup of boiling water has more thermal energy than a cup of cold water, which has more thermal energy than a cup of ice.
Usually is the last step in all energy transformations because it is so hard to store.

7. Chemical Energy The energy that is stored in chemical bonds
Is released when bonds between compounds are broken
Examples of substances that contain chemical energy:
Wood
Gasoline
Food

8. Radiant Energy (Light Energy)
Energy that is carried by light
Can be converted into thermal energy to warm objects
Light travels at 300,000 km/s, which is fast enough to circle the Earth eight times in one second.

9. Sound Energy
Energy that is transmitted through a medium in the form of vibrations.
Is a mechanical wave – requires material to travel through…cannot travel through a vacuum (No sound in space)
The denser the material, the faster sound will travel (travels fastest in solids)

10. Electrical Energy Energy carried by an electrical current
Caused by fast moving particles
These particles have charges that attract or repel each other.

11. Nuclear Energy Energy contained in the nucleus of an atom
Can be released two ways:
fission
fusion