1. Energy Chapter 5

2. What is Work? Work occurs when a force acts upon an object in the direction of the force applied If you push against a wall and the wall doesn’t move, have you done any work? Unit is the Joule (J)

4. What is Energy? The ability to do work Unit is the Joule (J) Energy can be transferred from one object to another

6. Reflect What do you think of when you think of energy? Draw a picture of what energy means to you.

7. Kinetic Energy Energy of motion Kinetic Energy depends on speed and mass Kinetic energy = mv 2 2 m is mass, v is speed (velocity) Speed has more of an effect on kinetic energy than mass does because speed is squared.

9. Reflect Draw a picture of something that has kinetic energy Do the math:  A 200 kg car is travelling at a speed of 10 km/hr. What is the kinetic energy of the car? Show all work

10. Potential Energy Energy of position or shape Ex.- the bow is not moving, but it has potential energy because work was done to change its shape

11. Gravitational potential energy Energy due to an object’s position above the earth’s surface The amount of energy is determined by the object’s weight and its distance above the earth’s surface Gravitational potential energy = weight x height

13. Reflect Draw a picture of something that has gravitational potential energy Do the math:  A toy is 40N and is on a shelf that is 10 meters above the floor. What is the gravitational potential energy of the toy? Show all work

14. Mechanical Energy Total energy of motion and position of an object Mechanical energy = potential energy + kinetic energy

15. Reflect Do the math:  A ball has a potential energy of 5 joules at the highest point of a bounce and a kinetic energy of 25 joules while the ball is moving. What is the total mechanical energy of the ball? Show all work

17. All forms of energy can be categorized as either kinetic or potential Potential  Stored energy  Energy of position  Chemical  Nuclear  Stored Mechanical  Sound Kinetic  Energy of motion  Waves, electrons, atoms, molecules, and substances  Radiant  Thermal  Motion  Sound  Electrical

18. Matter All matter is made up of particles in motion. Because the particles are in motion, they have kinetic energy. At higher temperatures particles move faster and therefore have more kinetic energy.

20. Reflect Draw pictures of the molecules in ice, water and steam in the boxes and answer the questions Which has the most energy – ice, water, or stream? Which has the least energy – ice, water, or steam?

21. Thermal Energy The total internal energy of the particles that make up an object. The vibration and movement of atoms and molecules within the substance. The faster the particles move, the more thermal energy they have The bigger the object is, the more thermal energy it has because there are more molecules that move Geothermal energy is an example of thermal energy

22. Reflect Name 3 things that have a little bit of thermal energy Name 3 things that have a lot of thermal energy Which has more thermal energy – the ocean or a lit match?

23. Chemical Energy Energy of a compound that changes as the atoms are rearranged Form of potential energy The more atoms that are bonded together in a compound, the more potential energy that compound has Energy stored in the bonds of atoms:  Biomass, petroleum, natural gas, propane and coal are examples  Food also has chemical energy

24. Photosynthesis uses light energy to make sugars Plants absorb the light in their leaves and change it to chemical energy When we eat, we absorb the chemical energy

25. Reflect Circle where you would find chemical energy HOHCl

26. Electrical Energy The energy of moving electrons Lightning and electricity Electricity is by the changing position of magnets so it can be considered a form of potential energy When you plug something in electrons move back and forth transferring energy so it is a form of kinetic energy Electrical energy is produced at power plants and then transferred to your home

27. Source: http://www.eia.doe.gov/kids/energyfacts/sources/electricity.html #HowIsATransformerUsed?

28. Reflect List 5 things you use daily that use electricity

29. Sound Energy Caused by an object’s vibrations Sound is the movement of energy through substances in longitudinal waves Is both potential and kinetic To make an object vibrate, work must be done You change the shape therefore you create potential energy When released, air particles are moved creating kinetic energy

30. Sound waves cause air to vibrate which transmit energy

31. Reflect Write a short song about sound energy to the tune of Mary Had a Little Lamb

32. Light (Radiant) Energy Radiant energy is electromagnetic energy that travels in transverse waves Light energy is an example of radiant energy Light energy is made up of photons which are little packets of energy Part of the electromagnetic spectrum

34. Electromagnetic Waves have different wavelengths When you listen to the radio, watch TV, or cook dinner in a microwave oven, you are using electromagnetic waves. Source: http://imagers.gsfc.nasa.gov/ems/waves3. html

35. Radio waves, television waves, and microwaves are all types of electromagnetic waves. They only differ from each other in wavelength. Wavelength is the distance between one wave crest to the next. Source: http://imagers.gsfc.nasa.gov/ems/waves3. html

36. Waves in the electromagnetic spectrum vary in size from very long radio waves the size of buildings, to very short gamma-rays smaller than the size of the nucleus of an atom.

37. Reflect Put the following in order of wavelength starting with the shortest and ending with the longest: Infrared; TV; X-rays; AM Radio; Visible light; Microwave

38. Nuclear Energy The energy within the nucleus of an atom Two types:  Fusion – this is done by the sun. It is when the nuclei of atoms are fused together thereby releasing a huge amount of energy  Fission – this is done by nuclear power plants. It is when the nuclei of an atom is broken apart thereby releasing a huge amount of energy

39. Is this Fusion or Fission? Reflect

40. Is this Fusion or Fission?

41. List two good things about nuclear energy List two bad things about nuclear energy