1. What is Energy? .

2. What is Energy?
The ability to do work or cause change.

3. What are the different forms of Energy?
Energy has a number of different forms, all of which measure the ability of an object to do work on or change another object.
In other words, there are different ways that an object can possess energy.

4. All types of energy can be transformed into other forms.
Forms of Energy
All types of energy can be transformed into other forms.
Mechanical
Potential Kinetic
Chemical
Nuclear
Light/Radiant
Thermal
Sound
Electrical

5. Energy Kinetic: The energy of an object due to it’s motion
the greater the mass or speed, the greater it’s kinetic energy
Potential: The energy of an object due to it’s position
the greater the mass or height, the greater it’s potential energy

6. Example A waterfall has both kinetic and potential energy.
The water at the top of the waterfall has stored potential energy.
Once the water leaves the top of the waterfall, the potential energy is changed into kinetic energy.

7. Mechanical Energy
Combined total of potential and kinetic energy of an object
Chains pulling up the roller coaster, hammer hitting a nail, turning on a flashlight

8. Chemical Energy Energy that comes from chemical changes
Stored in the connections between atoms
We use food for chemical energy so we can perform
Fuels produce chemical energy
Fire works
Batteries have stored chemical energy which changes to electrical energy when turned on

9. Nuclear Energy
Energy stored in the nucleus of an atom (holds the atom together)
Produced when an atom splits apart (Fission)
Nuclear power plant
Produced when 2 atoms join to form 1 atom (Fusion)
The sun’s energy is produced when Hydrogen (H) atoms fuse to form Helium (He).

10. Electrical Energy
Associated with the movement of electrons through a wire or circuit
Produced by electric charges
Power running the chains that pull up the roller coaster
generator has a loop of wire that spins creating an electrical current
Appliances use it to work

11. Radiant Energy Also called Light or Electromagnetic Energy
Travels in waves and can move through empty space
Energy carried by light and other kinds of EM waves
Sunshine, Visible Light, x-rays

12. Light / Radiant Energy
Travels in the form of electromagnetic waves, most of which we can not see.
Classified by wavelength (pg 309 SS)
Gamma rays have the shortest wavelength
Radio waves have the longest
Visible light is in the middle
All the colors of the rainbow
When they are all combined you see them as white light
Roy G Biv (name to remember order of colors)
Electromagnetic Spectrum: Full range of electromagnetic waves

13. Sound Energy
The energy of vibrations carried by matter (air, water, solids).
Sound waves canNOT travel through empty space
Telephone

14. Thermal Energy
Total Amount of Kinetic Energy contained in all particles of a substance
The more particles a substance contains, the greater the thermal energy
More thermal Energy does not mean a higher temperature.
Ocean is massive, therefore has more thermal energy than a pot of boiling water, but is not hotter.
Wood fire produces heat

15. Energy Transformations
All types of energy can be transformed into other types.
Law of Conservation of Energy:
Energy can not be created or destroyed. It can only be changed into other forms of Energy.

16. Temperature and Heat
TEMPERATURE The measure of the average kinetic energy of the particles in a substance. More kinetic energy = higher temperature
HEAT The transfer of thermal energy between substances that are at different temperatures.
Heat will transfer from the object with the higher temperature to the object with the lower temperature until the temperature is the same
Heat makes molecules move faster and spread. Heat spreads out in all directions.
Heat flows from warm water to the ice cubes, melting the ice as the water cools.

17. Transfer of Thermal Energy

18. Methods of Heat Transfer
CONDUCTION
CONVECTION
RADIATION

19. Conduction
Transfer of heat from a warmer substance to a cooler substance through direct contact
Energy from faster moving particles is transferred to slower moving particles until both are moving at the same speed and their temperature is equalized
Conductor: transfers heat very well (metal)
Insulator: does not transfer heat very well (wood)

20. Conductors and Insulators
Material through which energy can be transferred as heat
Metal is an excellent conductor, wood is not.
Insulator:
Material that reduces or prevents the transfer of heat
“Bad Conductors”.
Wood

21. Convection Transfer of heat (thermal energy) within liquids and gases.
Cold water on a hot stove
As the water on the bottom heats up, it becomes less dense (particles spread out)
Because the warm water is less dense than the cold water above it, the warm water rises and displaces the cold water, which sinks and warms.
Heat always moves from warmer to cooler areas
This movement of water is called a Convection Current: moves warm and cool molecules around until they are evenly mixed an the same temp.

22. Convection

23. Radiation Transfer of energy as electromagnetic waves
Can occur in empty space
Moves heat around in waves
Sun releases some it’s heat energy as infrared waves
Infrared Waves: low frequency light wave that is invisible to humans but felt as heat. (toasters, heaters)

24. Green House Effect