Energy and Its Forms

1. Energy and Its Forms Describe the relationship between work and energy. Relate kinetic energy to mass and speed. Analyze how potential energy is related to an object’s position and give examples of gravitational and elastic potential energy. Give examples of the major forms of energy and explain how each is produced.

2. In an avalanche, a mass of loose snow, soil, or rock suddenly gives way and slides down the side of a mountain. The avalanche releases a great amount of energy.

3. Energy and Work • Work is done when a force moves an object through a distance. • Energy is the ability to do work. • Energy is transferred by a force moving an object through a distance. • Work is a transfer of energy.

4. Energy and Work Energy has different forms. • The sun gives off energy in the form of heat and light. • Plants convert sunlight into food. • People convert food energy into muscle movement.

5. Energy Many forms of energy can be classified into two general types: Kinetic Energy Potential Energy

6. Kinetic Energy The energy of motion is called kinetic energy. The kinetic energy of any moving object depends upon its mass and speed.

7. Potential Energy Potential energy is energy that is stored as a result of position or shape. Two forms of potential energy are: Gravitational potential energy Elastic potential energy

8. Gravitational Potential Energy Potential energy that depends upon an object’s height is called gravitational potential energy. An object’s gravitational potential energy depends on its mass, its height, and the acceleration due to gravity. This type of potential energy increases when an object is raised to a higher level.

9. Potential Energy This diver has gravitational potential energy as she stands at the end of a diving board. She gained the potential energy by doing work—by climbing up the steps to the diving board.

10. Gravitational Potential Energy Place two items at different heights…WHICH DO YOU THINK HAS MORE POTENTIAL ENERGY? WHY? Gravitational PE depends on an objects height. GPE increases when an object is raised to a higher level. GPE depends on the mass of something, its height, and the acceleration due to gravity (g).

11. Potential Energy When this musician pulls the string of her cello to one side, the string is stretched and gains potential energy.

12. Elastic Potential Energy The potential energy of an object that is stretched or compressed is known as elastic potential energy. EX: springs, guitar strings, bike shocks

13. Elastic Potential Energy The musician adds energy to the cello string by plucking it. The energy stored in the stretched string is potential energy. The stored energy is converted into kinetic energy when the string is released and it vibrates.

14. Forms of Energy All energy can be considered to be one of three forms: Kinetic energy, Potential energy, and energy in fields such as those produced by electromagnetic waves. Each of these forms of energy can be converted into other forms of energy.

15. Forms OF ENERGY Mechanical Electromagnetic Electrical Chemical Thermal Nuclear

16. Energy due to a object’s motion (kinetic) or position (potential). The bowling ball has mechanical energy. When the ball strikes the pins, mechanical energy is transferred to the pins! What is Mechanical Energy?

17. Examples of Mechanical Energy

18. Mechanical Energy Not limited to machines. Mechanical energy is the sum of an object’s PE and KE.

19. Thermal energy = Heat energy The heat energy of an object determines how active its atoms are. A hot object is one whose atoms and molecules are excited and show rapid movement. A cooler object's molecules and atoms will show less movement. What is Thermal Energy?

20. Energy that is available for release from chemical reactions. The chemical bonds in a matchstick store energy that is transformed into thermal energy when the match is struck. What is Chemical Energy?

21. Examples of Chemical Energy When bonds are broken, the released energy can do work. All chemical compounds, including fuels such as coal and gasoline, store energy.

22. Forms of Energy This family is using the chemical energy of burning wood to produce thermal energy for heating marshmallows.

23. Energy associated with electric charges. Easily transported through power lines and converted into other forms of energy What is Electrical Energy?

24. Light energy or energy that travels through space in the form of waves. Includes energy from gamma rays, xrays, ultraviolet rays, visible light, infrared rays, microwave and radio bands What is ElectromagneticEnergy?

25. Forms of Energy Lightning bolts transfer electric charge. Galaxies are giant structures in space that typically contain billions of stars. The stars give off enormous amounts of electromagnetic energy.

26. Nuclear Energy The nucleus of an atom is held together by strong and weak nuclear forces, which can store an enormous amount of potential energy. The energy stored in atomic nuclei is known as nuclear energy. Nuclear fission releases energy by splitting nuclei apart. Nuclear fusion releases energy when less massive nuclei combine to form a more massive nucleus.

27. QUIZ TIME! What type of energy cooks food in a microwave oven? ELECTROMAGNETIC ENERGY What type of energy is the spinning plate inside of a microwave oven? MECHANICAL ENERGY

28. QUIZ TIME! What energy transformation occurs when an electric lamp is turned on? ELECTRICAL ENERGY  ELECTROMAGNETIC ENERGY

29. QUIZ TIME! Electrical energy is transported to your house through power lines. When you plug an electric fan to a power outlet, electrical energy is transform into what type of energy? MECHANICAL ENERGY

30. What types of energy are shown below? Mechanical and Thermal Energy (Don’t forget friction)

31. What types of energy are shown below? Electrical, Mechanical and Electromagnetic Energy

32. What type of energy is shown below? Chemical Energy

33. What type of energy is shown below? Thermal Energy

34. Draw a diagram showing the flow of energy transformations in a car from starting the vehicle to driving. You should have 5 different types of energy.

35. Energy Transfer Sound (mechanical) Electrical Thermal Mechanical Electrical Chemical Electrical Light (Electromagnetic)

36. Tomorrow… How do you know what you know?

37. Kinetic Energy Energy of motion. Kinetic energy of a moving object depends upon its mass and its speed. K.E. = m x v2 2

38. Potential Energy Energy due to position or stored energy. Gravitational Potential Energy (G.P.E) G.P.E = Wt. x Ht.

39. Law of Conservation of Energy Energy is never created or destroyed. Energy can be converted from one form to another but the total energy remains constant.