1. Energy: Forms and Changes

2. Nature of Energy Energy is all around you! –Y–You can hear energy as sound. –Y–You can see energy as light. –A–And you can feel it as wind.

3. You use energy when you: – hit a softball. – lift your book bag. – compress a spring.

4. Nature of Energy Living organisms need energy for growth and movement.

5. Nature of Energy Energy is involved when: – a bird flies. – a bomb explodes. – rain falls from the sky. – electricity flows in a wire.

6. Forms of Energy There are 7 main forms of energy : – Motion (kinetic) – Position (potential) – Thermal (heat) – Chemical – Light – Electrical – Nuclear

7. Within your groups: You will be assigned a type of energy to research. Using your text book starting on page 43. Make a paper power point slide describing the energy your group was assigned in order to teach the class about that energy.

8. Chemical Energy Chemical Energy is the energy stored in chemical bonds. And when bonds are broken, energy is released. Food contains chemical energy that your body uses to fuel your growth.

9. Chemical Energy Fuel and food are forms of stored chemical energy.

10. Where does the energy come from to make the flame burn?

11. Chemical energy is stored in the wax. When the wax burns, chemical energy is transformed into thermal and light energy Hence heat and light can be felt and seen!!

12. Light Energy! When light is absorbed by an object, the object can become warmer. The object transforms light energy into Thermal energy.

13. Radiant energy- Is the actual energy that is carried by light.

14. Thermal Energy Thermal Energy causes changes in temperature. Many chemical reactions that take place in your cells produce thermal energy. The energy to make the chemical reactions occur comes from Chemical energy! Thermal energy only moves from something that is hot to something that is cold.

15. All objects contain thermal energy, even if they are not hot. Thermal energy is the kinetic and potential energy created by the vibrations and motion of atoms. These tiny particles are always in motion in all the matter all around us. The thermal energy of matter/atoms would be lowest at 0K (absolute zero), where the atoms are barely moving (its too cold). The hotter the atoms are the faster they move/vibrate, which in turn makes them produce more thermal energy !!

16. Electrical Energy- the energy carried by an electric current. Power lines carry electrical (electromagnetic) energy into your home in the form of electricity.

17. Electrical Energy About 20% of all power used in the USA is generated by nuclear power plants

18. Nuclear Energy The nucleus of an atom is the source of nuclear energy.

19. Nuclear Energy When the nucleus splits (fission), nuclear energy is released in the form of heat energy and light energy. Nuclear energy is also released when nuclei collide at high speeds and join (fuse).

20. Nuclear Energy The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse to form helium nuclei.

21. Nuclear Energy Nuclear energy is the most concentrated form of energy.

22. Kinetic Energy-the energy of motion Is the energy an object has due to it’s motion. If an object isnt moving, it doesn’t have kinetic energy.

23. Kinetic Energy and Speed When you throw a balling ball, you give it energy. When that bowling ball hits the pins, some of the energy is transferred to the pins. The faster you throw the ball, the more kinetic energy it has.

24. Kinetic energy increases as an object moves faster. That’s why the faster you throw a balling ball, the more pins will fall down (due to more energy being transferred).

25. Kinetic energy and mass Which would knock down more pins… A bowling ball or a tennis ball? Soccer ball?

26. Potential Energy- the energy of position Potential energy is the energy stored in an object because of its position. Picture a glass of water on a table. It has no kinetic energy because it is not moving, it has only potential energy. What happens to the Potential energy if you were to push the glass off of the table? Is the glass in motion?

27. Transforming Energy How is energy transformed? What happens to a seat when you are sitting for a long time? What happens to a car when it is sitting in the sun? What happens when you eat? Lets see how different types of energy are transformed!!

28. Energy can be changed from one form to another. Changes in the form of energy are called energy transformations.

29. Energy transformations occur constantly all around you!! All forms of energy can be converted into other forms. – The sun’s energy through solar cells can be converted directly into electricity. – Green plants convert the sun’s energy (electromagnetic) into starches and sugars (chemical energy).

30. Chemical  Heat  Mechanical

31. States of Energy The most common energy conversion is the conversion between potential and kinetic energy. All forms of energy can be in either of two states: – Potential – Kinetic

32. Transforming Chemical Energy In your body, chemical energy is transformed into kinetic energy. Ex: Muscle cells When an organism dies, its body breaks down allowing bacteria and fungi to decompose the chemical compounds within the body into simpler chemicals/sugar that other organisms can use for energy.

33. Chemical energy can also be transformed into thermal energy. As these chemical compounds are broken down, they release energy in the form of heat. Ex: compost pile Fire works- chemicals react creating chemical energy which in turn gives off light energy (fireworks!!)

34. Transforming Electrical Energy Everything you plug into an outlet transforms electrical energy. Radio  kinetic energy of a speaker  sound energy (sound waves in air)  kinetic energy in eardrum  electrical energy of brain and nerve cells. After brain interprets sounds, the energy is transformed again into thermal energy!

35. Transforming Thermal Energy Chemical energy changes into thermal energy when something is burned. Electrical energy is transformed into thermal energy when the device gets hot Thermal energy can be used to heat water (an electric stove). Which in turn produces steam which transforms thermal energy into kinetic energy (molecules are hot and move around very fast).

36. That’s how steam engines are powered. Thermal energy  light energy What does very hot metal look like?

37. States of Energy: Kinetic and Potential Energy Kinetic Energy is the energy of motion. Potential Energy is stored energy.

38. Changing Kinetic and Potential Energy

39. 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.

40. 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.

41. Kinetic-Potential Energy Conversion Roller coasters work because of the energy that is built into the system. Initially, the cars are pulled mechanically up the tallest hill, giving them a great deal of potential energy. From that point, the conversion between potential and kinetic energy powers the cars throughout the entire ride.

42. Ball slows down Ball speeds up

43. The Law of Conservation of Energy Energy can be neither created nor destroyed by ordinary means. – It can only be converted from one form to another (just like you saw!) – If energy seems to disappear, then scientists look for it – leading to many important discoveries.

44. Law of Conservation of Energy In 1905, Albert Einstein said that mass and energy can be converted into each other. He showed that if matter is destroyed, energy is created, and if energy is destroyed mass is created. 2 » E = MC

45. Generating Electrical Energy Electrical energy is produced from power plants. Generators are used in power plants. Generators- a device that transforms kinetic energy into electrical energy.

46. In fossil fuel power plants: Coal, oil or natural gas is burned to heat up water. As the water boils, steam rushes through a turbine. Turbine- contains a set of fan blades. Steam pushes up on the blades and turns the turbine, which rotates a shaft in the generator to produce electrical energy. Show video Clip!

48. Power plants Different types of energy resources are used in different power plants to ultimately transform kinetic energy to electrical energy. Energy transformation in a coal burning power plant: Chemical energy of coal  thermal energy of water  kinetic energy of steam  kinetic energy of turbine  electrical energy out of generator!

49. Energy can not be created or destroyed. Energy can only change form!! Energy sources: The sun and radio active material from the interior of the Earth! (most energy comes from the sun)

50. Renewable vs. Non Renewable Resources Renewable resource- is an energy source that is replenished by the earth continually. Example:hydroelectricity Non Renewable: an energy source that is used up much faster than it can be replaced. Example:???????

51. Types of Energy Resources Fossil Fuels- Nuclear Energy- Hydroelectricity Solar Energy Geothermal Energy Tidal Energy Wind Power

52. Fossil Fuels Coal, oil and natural gas. Made from remains of microscopic organisms and plants that lived in the Earths oceans millions of years ago. Heat and pressure eventually turned these organisms into coal, oil and natural gas. Chemical energy is released when these fossil fuels are burned. Nonrenewable Causes pollution and acid rain

54. Nuclear Energy Made from the nuclei (the middle) of uranium atoms. Inside of uranium is unstable and breaks apart releases a giant amount of energy. Does not cause air pollution But Nuclear waste is very hazardous- Hard to dispose of, carcinogenic Uranium is nonrenewable- very rare to find it in Earth’s crust.

56. Hydroelectricity Transforms potential energy of water that is trapped behind dams. Supplies the world with 20% of its electrical energy. Largest renewable source of energy. Problem: It disrupts the life cycle of aquatic animals and ecosystems.

59. Solar Energy Inexhaustible (renewable) energy source: AS LONG AS THE SUN STILL EXISTS!! The sun is the origin of almost all the energy that is used on Earth. Does not cause pollution- Only.1% of energy in the US comes from Solar

60. How it works Using a thermal collector (which is black), the suns radiant energy it absorbed. Water circulating in the system is heated. The hot water is circulated through the house to heat it up. Photovoltaic- does not have pipes. Transforms radiant energy into electrical energy. This is how calculators and satellites are powered.

62. Geothermal Energy Uses Geothermal reservoirs : Where rainwater seeps down through cracks to the hot rock towards the center of the earth. It heats up producing trapped steam (containing a lot of energy)

63. The steam and hot water are than used by Geothermal power plants Renewable resource, but the problem is, these power plants can only be built where these geothermal reservoirs are found.

64. Heat Pumps Summer-air is warmer than underground temp. Warm water is pumped from building into ground. Water is cooled by underground lower temp and than pumped back into the house. Winter-ground water is hotter, so reverse happens.

65. Tidal Energy As a tide comes in, it turns a turbine connected to a generator. When high tide occurs, gates are closed that trap water behind a dam. As tide goes out and ocean level drops, gates are opened and water from behind the dam flows through the turbine, causing it to spin and turn generator, producing electricity.

66. Wind Power Renewable Windmills converts (transforms) kinetic energy of the wind into electrical energy. The propeller is connected to a generator, so when propeller spins, it causes generator to produce electricity. Negative: very loud, kills birds, what happens if there is no wind that day?

68. Energy Conservation After completing your worksheet: Work within your groups to come up with a Poster on how to Conserve Energy. Your poster should be eye catching and advertise ways to save energy by