1. ENERGY: What do we remember?

2. ENERGY Where is energy found and when? Energy is around you all the time What is energy? Ability to do work When work is done, what happens to energy? Energy is given off What is the SI unit for energy? Joules (J) Energy has the same SI unit as what? Work

3. What are the two states of energy?

4. What can you tell me about KINETIC ENERGY?(KE) Greek = kinetikos = “moving” Energy of motion/movement Depends on mass and speed KE = mv 2 2 ↑ speed = ↑ KE ↑ mass = ↑ KE Speed has greater effect than mass

5. What can you tell me about POTENTIAL ENERGY (PE) Energy of position/shape Stored energy Gravitational Potential Energy (GPE) – (GPE) = weight x height – N x m = J

6. MECHANICAL ENERGY (ME) Objects total energy of motion and position ME = PE + KE PE ↑ = KE ↓ PE ↓ = KE ↑ ME remains constant

8. 8 Pendulum

9. 9 Car on an incline

10. Energy can take different forms…

11. THERMAL ENERGY KE Total energy of particles (atoms and molecules) that make up object ↑ movement = ↑ KE = ↑ temp. = ↑ thermal energy Particles far apart have more energy than particles close together.

12. Energy vs. Thermal energy Least Mostenergy most thermal energy Particle movement Amount of particles

13. CHEMICAL ENERGY PE Compound energy that changes arrangement of atoms Stored in bonds between atoms Chemical rxn takes place

16. ELECTRICAL ENERGY KE Moving electrons back and forth through wire or current Produced at power plants

18. SOUND ENERGY PE and KE Energy of vibrations Transmits energy to air Carried through solids, liquids, and gases Travels in waves

19. LIGHT/RADIANT ENERGY Not all light can be seen Vibrations of electrically charged particles Travels through waves and empty space

20. NUCLEAR ENERGY Produced from change of nucleus Two types – Fission: splitting nucleus (electrical energy) – Fusion: joining nuclei (sun) Uranium: – stores a lot of PE – energy used from nuclei being split – generated at nuclear power plants

22. VENN DIAGRAM OF FORMS OF ENERGY POTENTIAL ENERGY KINETIC ENERGY CHEMICAL NUCLEAR THERMAL ELECTRICAL LIGHT/RADIANT SOUND

23. ENERGY CONVERSIONS Transfer/change/conver sion of energy from one form to another Can be transferred converted to more than one form

24. Energy Conversions “Breakfast is the most important meal of the day.” Eating Being active Body temperature Chemical Energy Kinetic Energy Thermal Energy

25. Energy Conversions electrical light and sound chemical electrical kinetic and sound electrical light and thermal electrical kinetic, thermal, and sound

26. Energy Conversions

29. Explain the energy conversions below.

30. ENERGY AND MACHINES Machines make work easier by changing – Size – Direction – or both of the force required to do the work Machines transfer energy and convert energy

31. Why are energy conversions important? It is useful for every day life. – Ex. Wind used to cook a meal Efficiency – Ex. Energy efficient light bulbs and appliances

32. WHERE DOES THE ENERGY GO? Energy is never lost but converted to other forms of energy Hills and friction help to tell what happens to energy Energy is used to overcome friction Some of the energy is always converted to thermal energy

33. Law of Conservation of Energy Energy can neither be created or destroyed Closed system- well-defined group of objects that transfer energy between each other. Total amount of energy always the same Ex. Roller coaster, light bulb

34. Perpetual motion machine Runs forever without additional energy Energy in = Energy out Will never happen because some energy is turned into thermal energy.

35. REFERENCES http://www.glenbrook.k12.il.us/gbssci/phys/ mmedia/energy/ce.html http://www.glenbrook.k12.il.us/gbssci/phys/ mmedia/energy/ce.html http://www.physicsclassroom.com/mmedia/energy/se.html