Forms of energy g6

Kinetic energy

1. What is Energy? The word energy comes from the Greek word “Energos ” which means active Energy is the ability to cause change

2. Energy… …is the ability to make things move

3. The seven types of energy … Chemical - gasoline, Light – sun, Heat – burner, Nuclear , sun Mechanical - car, Sound – music on the radio, Electrical - lightning

4. Kinetic energy: It’s the energy an object has due to motion Example: A moving bowling ball has energy that causes the pins to fall . This energy is called kinetic energy. Kinetic Energy

5. The sky diver has kinetic energy A ball kicked by a football player has a kinetic energy

6. Mass, Speed and Kinetic Energy All moving objects have kinetic energy. Not all moving objects have the same amount of kinetic energy. The amount of kinetic energy an object has depends on the mass and the speed of the object

7. Imagine those two rocks are rolling down the hillside with the same speed. Which one will have more kinetic energy? Which one will cause more damage if they hit something at the bottom? The larger rock could cause more damage because it has larger mass and has more kinetic energy than the smaller rock

8. Kinetic energy also depends on speed . The faster object has more speed and has more kinetic energy

9. Transferring kinetic energy Kinetic energy could be transferred from one object to another when they collide . The bowling ball does not touch all the pins but it can knock them down with one roll . The bowling ball transfer kinetic energy to few pins. The pins will transfer this kinetic energy to each other and knock them down

10. A transfer of kinetic energy takes place when dominos fall. When you tap the first domino you give it a kinetic energy Then the domino will fall into the next one and the kinetic energy will be transferred from one domino to another

11. This skater has no kinetic energy as she’s standing at the top of the hill and not moving . As the skater moves down , she is moving faster and her kinetic energy increases.

12. Gravity pulls the skater down the hill. If the skater was standing at the bottom of the hill, gravity wouldn’t start her moving. When the skater is at the top of the hill, she has a form of energy called Potential energy

13. Potential Energy It’s the energy that is stored because of an object’s position. The Higher an object is lifted above earth, the greater is it’s potential energy

14. Converting potential and kinetic energy

15. Whe n you throw a ball upwards it is moving the fastest so it has maximum kinetic energy As the ball moves upward , it slows down and stops for an instant As the ball moves downward it speeds up and the potential energy is transferred into kinetic energy

16. Energy changes in falling water Is converted to

17. Water at the top of the dam has potential energy. When water falls downwards the potential energy changes into kinetic energy The kinetic energy in the moving water spins the generators and that’ll produce electrical energy

18. KE and PE In many situations, there is a conversion between potential and kinetic energy. The total amount of potential and kinetic energy in a system is called the mechanical energy Mechanical energy = PE + KE

19. Mechanical Energy The mechanical energy does not change because the loss in potential energy is simply transferred into kinetic energy. The energy in the system remains constant!! The total amount of energy stays the SAME!!

20. Mechanical Energy The energy of movement. This energy includes both kinetic energy (motion) and potential (stored) energy

21. Mechanical Energy Mechanical energy is due to the position and motion of the object. What happens to the mechanical energy of an apple as it falls from a tree?

22. Mechanical Energy As the apple falls to the ground, its height decreases. Therefore, its PE decreases . The potential energy is not lost… it is converted into kinetic energy as the velocity of the apple increases. What happens to the mechanical energy?

23. Swinging Along Think about the changes in energy when you are on a swing… At what point do you have the most potential energy? At what point do you have the most kinetic energy? What happens to the mechanical energy?

24. Conversion of Energy

25. Mechanical Energy The energy of movement. This energy includes both kinetic energy (motion) and potential (stored) energy

26. Electrical Energy A form of energy that is produced when electrons move from one place to another place

27. Light Energy A form of energy that travels in waves and can move through empty space where there is no air.

28. Thermal Energy The energy of moving particles in a substance; also called heat energy

29. Sound Energy A form of energy produced by vibrating objects.

30. The Law of Conservation of Energy The Law of Conservation of Energy states that energy cannot be created or destroyed. The big picture… the total energy in the universe remains constant.

31. Energy in Your Body Even the energy converted in your body follows the law of conservation of energy. Chemical potential energy is transferred to kinetic energy that allows your body to move!!

32. Calories… A Calorie (C) is a unit to measure energy in foods. 1 Calorie is equal to about 4,184 Joules. A person uses about: 55 Calories while sleeping for 1 hour 210 Calories while walking for 1 hour 850 Calories while running for 1 hour

33. Changing forms of Energy An example of transforming chemical energy is a car engine. Chemical potential energy in gasoline is transformed into kinetic energy of the car as it moves!!

34. But how? If I stop pumping while I’m swinging, I stop!! So, where’s the energy?

35. Conservation of Energy Energy is transformed… not destroyed!! The total amount of energy stays the SAME!!