7. We will talk about each kind of energy, starting withMechanical
8. Every moving object has mechanical energy,whether it is a hammer driving a nail, a leaffalling from a tree, or a rocket flying inspace. Any object that is moving can causeanother object to move. Mechanical energypulls, pushes, twists, turns and throws. A moving hammer has mechanical energy. When it hits the nail, it causes the nail to move.
9. When you hit a ball with a bat, the ball flies.What causes the ball to move when it hitsthe bat?What about when you kick a ball. Whatcauses the ball to move? Both the bat and the kicking feet have mechanical energy; they caused the balls to move.
10. NEXTSound
11. Sound energy involves vibrating objects. When you strike a tuning fork, it vibrates back and forth and makes a sound.
12. When a boom box produces sound, the speakersvibrate.
13. When something vibrates it causes the airaround it to vibrate as well. These vibrationsmay travel to our ear. Our brain interprets thevibrations of a violin string as music.
14. It works like this: the vibrations travel throughthe air to our ear, are sensed by our ear drumwhich moves little bones, causing fluid in acanal to move tiny sensor hairs. Our brainsenses the motion of these hairs as sound.
15. Thermal
16. Thermal energy exists because objects have heat.Heat is caused by the motion of the tiny particlesthat make up everything. Just as TV pictures aremade up of tiny pixels, everything is made up ofatoms and molecules. These tiny particles are alwaysin motion but we can’t see them or the motionbecause they are so small. But we know the fasterthey move, the hotter they get.When an object absorbsthermal energy, the moleculesand atoms that make up thatobject move faster and itstemperature rises.
17. Rub your hands together. What did you notice?Yes, they got warmer. Why do you think thatmight happen?When you rub your hands together, you createfriction which causes heat between your hands.This heat that you feel is there because the frictioncaused the molecules that make up your skin tomove faster. As a result, you increased theamount of thermal energy in your hands and theyfeel warmer.
18. We use thermal energy to cook our food,to heat our homes, to generate electricityand many other things.
19. Aren’t you glad thatsomeone discoveredthat thermal energychanges matter. Lookwhat changes occurwhen we bake a cake.
20. ICE WATER VAPOR ICE WATER VAPORAdding and subtracting thermal energy canalso change matter from one form to anotherby making molecules move faster or slower.
21. Electrical
22. Electricity is the energy of electrons moving in anelectrical conductor, like wire. Electrons,remember, are one of the three particles of whichevery atom is made. All matter consists of atoms, and every atom contains one or more of these electrons, which are always moving. When electrons are forced along a path in a conducting substance, the result is a current of energy called electricity.
23. This is a diagram of anelectric current ofelectrons moving in aclosed circuit. What doyou notice happens whenthe circuit is open?.
24. Many things that are very useful to usrun on electrical energy.
25. Chemical
26. Energy stored in the bonds of atoms and molecules iscalled chemical energy. When some substancesreact with one another, chemical energy is released.Probably the most familiar example of chemicalenergy is the dry cell battery that you use so often. metal cap (+) When these different carbon rod (positive substances react with electrode) zinc case (negative each other, electric electrode) manganese (IV) oxide energy is released providing power for moist paste of ammonium chloride your flashlight, radio, metal bottom (-) or whatever.
27. Photosynthesis is perhaps a more importantexample of chemical energy. Plants absorb lightenergy from the sun which causes a reactionbetween the carbon dioxide and water in plantleaves creating a sugar called glucose. Plants canchange glucose into carbohydrates and fats,storing chemical energy for later use.
28. This “stored for later use” covers a lot ofterritory. It could be: •Used by the plant itself for growth and survival.
29. This “stored for later use” covers a lot ofterritory. It could also be: •Plant parts could be eaten by animals, starting a food chain for feeding earth’s creatures.
30. Plant absorbs light energy and transforms it into Energy transfer in food chains chemical energy The grass is eaten by the _________is eaten by the _____is eaten by the ______is eaten by the ______.Stored _________ energy in the plants is transferredfrom the __________to the_____, to the _____tothe ________enabling each to live and reproduce.Where did the plant get the energy to make food withstored chemical energy?
31. Just as animals, we humans must eat and digestsubstances (like fruit, vegetables, and even meat ofanimals that had eaten plants). In the process, thechemical bonds between the atoms and molecules inthe food are broken down, releasing chemic