ENERGY

1. ENERGY THE ABILITY TO CAUSE CHANGE

2. Bill Nye clip on energy http://www.youtube.com/watch?v=7gX0mgzpLR8

3. Energy CLIP • Energy is the capacity (ability) to do work.  • Kinetic Energy: Associated with an object in motion • Potential Energy: Present in an object that has the potential to move because of its position

4. Kinetic Energy • KE of an object depends upon two variables: • the mass (m) of the object • the speed (v) of the object.

5. Calculating Kinetic Energy A formula to find the kinetic energy of any body based on its velocity.

6. Kinetic Energy The greater the mass or velocity of a moving object, the more kinetic energy it has.

7. Potential Energy • An object can store energy as the result of its position.

8. A C D E B C B A All potential energy (stops for an instant) P.E. = 9 J K.E. = 1 J All potential energy (stops for an instant) P.E. = 10 J K.E. = 0 J All kinetic energy (greatest speed) K.E. = 10 J P.E. = 0 J E D Potential energy & Kinetic energy P.E. = 4 J; K.E. = 6 J Potential energy & Kinetic energy P.E. = 5 J; K.E. = 5 J

9. Forms of potential energy Gravitational Nuclear Chemical -position above the Earth’s surface -stored in the nucleus of an atom -chemical reaction

10. Gravitational Potential Energy • GPE is the energy stored in an object as the result of its vertical position (i.e., height). • Amount of GPE is dependent on two variables: • the mass • the height

11. Calculating Gravitational Potential Energy GPE = mgh (rate an object falls due to gravity) g = 9.8m/sec2

12. Nuclear Energy Nuclear energy is the energy stored in the nucleus of an atom. Nuclear energy is unusual in that it can give off energy in the form of light or heat, but it is the change in the atom's makeup that produces the energy.

13. Nuclear Energy All power plants convert heat into electricity using steam. At nuclear power plants, the heat to make the steam is created when atoms split- fission. Fission takes place when the nucleus of a heavy atom like plutonium or uranium is split into two when struck by a neutron. This releases more neutrons which repeat the process and releases more nuclear energy (heat). This heat boils water and creates steam that turns a turbine. As a turbine spins, the generator turns and its magnetic field produces electricity that goes to your house.

15. Chemical Energy Chemical energy is the energy stored in the bonds of atoms and molecules. This a form of potential energy until the bonds are broken. Examples: Fossil fuels store chemical energy. Products that contain chemical energy include: TNT, baking soda, and a match. Biomass, petroleum, natural gas, propane and coal are examples of stored chemical energy.

16. Kinetic Energy Radiant Sound Thermal Electrical

17. Radiant Energy Radiant energy is also called electromagnetic energy or light energy. All life on earth is dependent on radiant energy from the sun. Examples: radio waves (AM, FM, TV), microwaves, X-rays, and plant growth. Active solar energy uses photovoltaic panels and light to turn radiant energy into chemical energy.

18. Electromagnetic Spectrum • Electromagnetic Spectrum—name for the range of electromagnetic waves when placed in order of increasing frequency GAMMA RAYS ULTRAVIOLET RAYS RADIO WAVES INFRARED RAYS X-RAYS MICROWAVES VISIBLE LIGHT

19. Sound Energy Sound energy is the movement of molecules in the air that produces vibrations. EXAMPLES: Alarms, music, speech, ultrasound medical equipment all use sound energy. VCR tapes change sound energy into electrical energy by electrical energy recording the sound using magnetic tape. Speakers read the magnetic tape and change it back into sound.

20. Since radio waves can carry energy, we use them to transmit information by varying the frequency and/or the amplitude of the radio wave to encode a message. For example, a radio transmitter turns a human voice into waves by varying the frequency of radio waves in the same pattern as the sound waves measured by a microphone. This is called frequency modulation or FM. Another way to encode information in radio wave is by varying the amplitude of the waves, called amplitude modulation or AM. The numbers on the radio dial represent radio waves at different frequencies measured in MegaHertz (Mhz are equivalent to 1 million waves per second) or kiloHertz (kHz,1000 waves per second). By tuning your radio receiver, you make it sensitive to radio waves produced at different wave frequencies. Many thousands of messages carried on radio waves are passing through and around you right now, but you need a radio receiver to detect and decode them.

21. Thermal Energy Thermal energy is the internal energy in substances - the vibration and movement of atoms and molecules within substance. Thermal energy is created in the movement of atoms. EXAMPLES: Boiling water, burning wood, and rubbing your hands together really fast. Geothermal and passive solar are sources of heat energy.

22. Electrical Energy Electrical energy is the movement of electrons. Examples: Lightning and static electricity occur naturally. Science hasn't found a way to use natural forms of electrical energy. We use different energy sources to create electrical energy by using generators and turbines.

24. Mechanical Energy Mechanical energy is the movement of machine parts. Mechanical energy comes from the motion (kinetic energy) and position (potential energy) of objects. EXAMPLES: Wind-up toys, grandfather clocks, and pogo sticks Wind power uses mechanical energy to help create electricity. Potential energy + Kinetic energy = Mechanical energy