Energy: What is it? Forms and States

1. Energy: What is it? Forms and States Catherine WalkerAmerican Public University

2. What is Energy? • Energy is defined as the ability to do work. • If an object or organism does work, the object or organism uses energy. • Energy makes everything happen.

3. Energy is all around you! • You can hear energy as sound. • CRASH! BANG! Did you hear that sound? It was made by air vibrating. • You can see energy as light. • Items such as light bulbs and television screens give off this light energy. • You can feel energy as wind. • Windmills and sailboats are powered by wind energy.

4. Living Organisms Living organisms need energy for growth and movement. Your body uses energy Even if you’re not moving. Your body uses energy even If you’re asleep or resting. Food contains nutrients which Produce energy and help to Grow and repair the body. Your body needs enough food to keep itself at the right temperature. You use more energy if you’re Active, and less if you’re resting. Energy is needed to pump Blood around your body.

5. We are always using energy • You use energy when you: • Hit a baseball • Ride a bike • Compress a spring • Lift your backpack How have you used energy today?

6. Energy is used for… Can you give an example of how energy is used for residential and commercial, industrial, or transportationpurposes?

7. Energy Conversion Energy cannot be created or destroyed; it can only be changed from one form to another. When energy changes from one form to another the process is called energy conversion. • The sun’s energy through solar cells can be converted directly into electricity. • In an electric motor, electromagnetic energy is converted to mechanical energy. • In a battery, chemical energy is converted into electromagnetic energy. • The mechanical energy of a waterfall is converted to electrical energy in a generator.

8. Energy Conversion Example Green plants convert the sun’s energy into chemical energy through the process of photosynthesis.

9. States of Energy • Kinetic Energy is the energy of motion. • Potential Energy is stored energy.

10. States of Energy

11. Kinetic Energy • The energy of motion is called kinetic energy. • The faster an object moves, the more kinetic energy it has. • The greater the mass of a moving object, the more kinetic energy it has. • Kinetic energy depends on both mass and velocity. What has a greater affect on kinetic energy: mass or velocity? Why? KE = mass x velocity2 2

12. Potential Energy • Potential Energy is stored energy. • Stored chemically in fuel, the nucleus of atom, and in foods. • Or stored because of the work done on it: • Stretching a rubber band. • Winding a watch. • Pulling back on a bow’s arrow. • Lifting a brick high in the air (known as Gravitational Potential Energy).

13. Gravitational Potential Energy Water behind a dam, a bolder sitting on a hillside, an apple hanging from tree all have gravitational potential energy.

14. Gravitational Potential Energy PE = m (mass) x g (gravity) x h (height) A cinder block that weighs 60 kilograms is sitting on a platform 20 meters high. How much gravitational potential energy does it the cinder block have? 60 x 9.8 x 20 = 11,760 Joules of gravitational energy potential

15. Joules – How Energy is Measured • Both kinetic energy and potential energy are measured in Joules. • James Prescott Joules (1818-1889) was a British physicist who established the mechanical theory of heat and discovered the first law of thermodynamics. • Joules don't equal watts—one is a measurement of energy, oneis a measurement of power. • 1 Watt = 1 Joule used per each second.

16. Common Forms of Energy • Chemical • Electrical • Light • Mechanical • Thermal (heat) • Nuclear Note: Not meant as a complete list of energy types.

18. Online Quiz

19. Key Concept: Law of Conservation of Energy • The total amount of energy in the universe is constant. • Energy can be neither created nor destroyed. • It can only be converted from one form to another.

20. Complete Energy Worksheet

21. Vocabulary Words Electrical energy Energy Energy conversion Gravitational potential energy Joules Kinetic energy Law of conservation of energy Potential energy Light energy Mechanical energy Nuclear energy Thermal energy Complete Concept Map

22. Images used for educational purposes only. PowerPoint inspired by: education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt Sources Slide 1: http://www.conserve-energy-future.com/Images/Energy_Sources.jpg Slide 2: http://www.unleashyourvitality.com/wp-content/uploads/2010/03/energy.jpg Slide 4: http://www.grainchain.com/images/topics/11-14/energyOut.png Slide 5: Baseball: http://www3.pictures.gi.zimbio.com/Olympics+Day+10+Baseball+JOgQPeBHoVrl.jpg Bicycle: http://westernskycommunications.com/images/bicycle-photography-ua-criterium-11-cornering.jpg Spring: http://crfsonly.com/howto/keihin-fcr-carb/honda-crf-hot-start/how-to-install-zip-ty-hot-start-nut.php Backpack: http://www.zimbio.com/pictures/retd20EgMW4/Olympics+Day+10+Baseball/JOgQPeBHoVr/Sun+Lingfeng Slide 6: http://205.254.135.7/energy_in_brief/major_energy_sources_and_users.cfm Slide 8: http://www.dynamicscience.com.au/tester/solutions/electric/energyconversions.htm Slide 9: http://www.petervaldivia.com/technology/energy/image/potencial-and-kinetic.bmp Slide 10: http://www.youtube.com/watch?v=7K4V0NvUxRg&feature=related Slide 13: Bolder: http://www.bbc.co.uk/schools/ks3bitesize/science/images/boulder.jpg Dam: http://zonalandeducation.com/mstm/physics/mechanics/energy/gravitationalPotentialEnergy/wtrfl1.jpg Apple: http://gurneys.com/images/250/12958.jpg Slide 17: http://glencoe.mcgraw-hill.com/sites/dl/free/0078695104/160350/00076705.swf Slides 5, 6, 11, 14, 18, 20, and 21: http://bicycledriving.org/enforce/traffic/images/knowledgecheck.jpg Slide 19: http://www.frankswebspace.org.uk/ScienceAndMaths/physics/physicsGCSE/efficiency.htm