Energy is the ability to do work, cause things to happen and make changes.

Transcription

1 What is Energy?

2 Energy is the ability to do work, cause things to happen and make changes. PBS NOVA Now - Energy How do weuse ener gy?

3 Examples of Potential and Kinetic Energy When the ball is not moving it has potential energy. Kinetic Energy Examples: The motion of the planets orbiting the sun Running, hopping, skipping A skydiver jumping out of a plane Potential Energy Examples: A yo-yo in your hand A spring that is compressed A bike at the top of a hill As it rolls down the hill it loses potential energy and gains kinetic energy.

4 What is potential ener gy? What is kinetic energy? There are many forms of energy but they can all be put into two categories: Potential Energy Potential Energy is stored energy and the energy of position. Chemical Mechanical Nuclear Gravitational Kinetic Energy Kinetic energy is the motion of waves, electrons, atoms, molecules, substances, and objects. Radiant Thermal Motion Sound Electrical

5 Ener gy Exper iment Potential vs. Kinetic Energy: If we hold a ball 20 cm above the floor does it have the same potential energy as a different ball? Tr y it! Find your partner and choose two different types of balls Try dropping a ball 20 cm off the floor Next, try dropping another ball 20 cm off the floor What happened? Use a ruler to determine the height from which you are dropping the balls Record the height of the bounce

6 Ball Bounce Exper iment Make a table on your paper to record your results. Height of Ball vs. Ball Bounce Type of Ball Starting Height (20 cm) Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Ball #1 Ball #2 Bounce Height (cm) Bounce Height (cm) When you are done, transfer your information to a Google Slides presentation. You may make your own or share it with your partner. We will add to it next week.

7 Ball Bounce Exper iment Make a table on Google Slides to record your results. Height of Ball vs. Ball Bounce Type of Ball Starting Height (20 cm) Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Ball #1 Ball #2 Bounce Height (cm) Bounce Height (cm) After completing the table try this:

8 Wher e does ener gy come f r om? Experiment: What will happen to the temperature of the water in the pan if we leave it in the sunlight for 45 minutes?

9 The Coiled Snake Hold the snake by the string over a candle or light bulb. As the light bulb heats up, the snake should spin. Explanation: When t he candle bur ns, t wo f or ms of ener gy ar e r eleased, heat and light energy. The heat causes the air to rise up, which in turn makes the snake spin ar ound. (The snake does not move up because t he coiled shape of t he snake allows the heat to rise through the middle and spin the snake.) Class discussion: The ener gy we need comes f r om t he f ood we eat. The ener gy r equir ed t o t ur n t he pedals of a bicycle comes f r om t he per son r iding t he bicycle. Car s and t r ucks get t heir ener gy f r om gasoline. Some homes ar e heat ed using oil or natural gas or firewood. When designing heating and cooling systems, engineer s st udy t her mal ener gy and how it cr eat es air movement. They place heat vents and radiators low, near the floor because they know that hot air rises. As hot air rises it mixes with the existing room air, preventing "cold" spots and making t he space mor e comf or t able. The same is t r ue f or cool air vent s t hat ar e placed high, near the ceiling. The cool air sinks, evenly mixing with the existing r oom air.

10 1. What we know: We know that energy gives off heat or light. We know that energy causes movement. Item that uses energy: Ener gy Det ect ives We know that ener gy 2. What we found: We know it uses energy because... Source of energy for this item:

11 What ar e r enewable ener gy r esour ces? What are nonrenewable energy resources? Wher e does ener gy come f r om? Nat ur al ener gy sour ces: f ood, wat er, plant s, t r ees, gravity, sun, fossil fuels, uranium, plutonium Ways that humans have harnessed or converted natural ener gy sour ces: hydr oelect r ic dams, coal/oil power plants, nuclear power plants, wind turbines, solar panels, et c.

12 How do we get ener gy int o our homes? The sun produces light energy Plants turn the light energy into chemical energy Plants are fossilized and compressed into fossil fuels such as coal and oil Fossil fuels are burned in power plants to produce electricity for our homes and businesses

13 What ar e sour ces of ener gy? Renewable Nonrenewable

14 How do Solar Panels Wor k? Solar Panels are made up of photovoltaic cells or PV cells. 1. When sunlight hits the cells the photons cause the release electrons in the panel. This creates a current or flow of electrons travel down wires to an inverter where they are changed from DC current to AC current.

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16 Kinetic energy Vocabular y En er gy Renewable Nonrenewable Sola r Win d Fossil fuels Potential energy

17 Slinky Experiment *Draw this table on your notes page Type of Wave What does it look like? Longitudinal Transverse

18 Slinky Waves - Waves are created by vibrations. Vibrations are the sources of sounds. On your sketch note, draw pictures of what you see happening with each type of wa ve. Which way do the waves move? What happens when the wave hits the end of the slinky? Can you think of other places where you see waves?

19 Sl i nk y Wav es - Longitudinal Waves- Sound Waves

20 Sl i nk y Wav es - Tr ansver se Waves - Wat er Waves

21 I Used t o Think... But Now I Know...

22 What is energy? To illu m in a t e lig h t s The ability to do work or cause change. Work is the application of a force through a distance. (Ask the students for exam ples, such as m oving a box across the room, sweeping, etc.) - Force can put m atter into m otion or stop it if it is already m oving. - Mot ion is a ch a n g e in p osit ion of a n ob je ct w it h t im e. To do work, energy is needed. From where does energy come? Na t u ra l e n e rg y sou rc e s: fo o d, w a t e r, p la n t s, t re e s, g ra vit y, su n, fo ssil fu e ls, u ra n iu m, p lu t o n iu m Ways that humans have harnessed or converted natural energy sources: hydroelectric dams, coal/oil power plants, nuclear power plants, wind turbines, solar panels, etc. What are different types of energy? (Se e t h e Vocab u la ry / De fin it ion s se ction.) Kin e t ic e n e rg y: e le c t ric a l, lig h t, t h e rm a l, sola r, sou n d, w in d, h yd ro Potential energy: chem ical, m echanical, nuclear, gravitational How do we use energy? To break down and digest food (in our bodies) To heat houses and other buildings