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Minority and Female Physics Heros Electro-Magnetic Induction Wind Farms: How do we harness the energy from the wind? Resources/Materials: Computer with internet access, battery in holder, wire, compass, bar magnet, paper, galvanometer Magnetism Basics: You overheard a friend make the following statement: “this paper clip will be attracted to a magnet because all metals are magnetic.” Evaluate your friends response; state whether you agree or disagree and given evidence for this. ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... Devise a test and then run it for the above statement. Write the procedure below and then share the results with the class. ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... Magnetic Fields, Observations Place a bar magnet on the table. Put a piece of paper over it. Gently sprinkle iron fillings on top of the paper. Write down what you observe. In the space to the right include a picture of what you see. ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ....................................................................................................................................................................................................... ELECTRO-MAGNETIC INDUCTION 2 Go to the PhET link, http://phet.colorado.edu/simulations/ click on physics, then click on “Electricity, Magnets & Circuits” and click on the “Faraday’s Electromagnetic Lab”. The first tab shows a magnet and a compass like shown in the Figure. The magnet results on a magnetic field. This is represented by the small compasses shown throughout. The stronger the magnetic field, the brighter are the small compasses. The larger compass can be used to visualize the effect of the magnetic field on a small magnet (the magnet of the compass). How is this simulation similar to and different from the previous activity? .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Take your battery and connect a wire to either end, forming a circuit. Move your compass on top of the wire. Observe what happens. Then, move your compass BELOW the wire. What happens? (Hint: What is a compass used to measure?) .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Come up with a model that describes this phenomenon. Compare the results with your classmates. .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Magnetic Fields, Testing Many principles in physics show symmetry. What would be this symmetrical relationship based upon the previous activity? .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... If you took a galvanometer (which can be used to measure small currents) then what should you expect to happen when you coil up the wire and move the magnet back and forth through the inside of the coil? .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... ELECTRO-MAGNETIC INDUCTION 3 Run the experiment and describe the results. .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Applications: Click on the “Pickup Coil” tab. You should observe something similar to what is in the Figure. You have freedom to modify several features in this simulation. What are the six changes that result in the light bulb giving off light? (Hint: moving the magnet left, moving the magnet right, moving the magnet up, etc, all count as one: moving the magnet) 1. ................................................................................................................................................................................................. 2. ................................................................................................................................................................................................. 3. ................................................................................................................................................................................................. 4. ................................................................................................................................................................................................. 5. ................................................................................................................................................................................................. 6. ................................................................................................................................................................................................. For how long does the bulb give off light? (Hint: the answer does involve a specific time interval nor something like “just a short amount of time”) .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Electrical Generator Now click on the “Generator” tab. You should observe something similar to what is in the Figure. It helps to visualize what is happening by clicking on “show magnetic field.” This simulation illustrates the concept of an electric generator. You can change the strength of the magnet, the loop area and the number of loops for the coil. You can also regulate the amount of ELECTRO-MAGNETIC INDUCTION water flow. Manipulate, one at a time, each of the parameters, and describe in your own word the recipe for producing electricity. .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Describe the process from start to finish that allows windmills to generate electricity. .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Research Extension Research wind farms write down some key arguments for and against wind farms. Be sure to include any information you find surprising as well as information on the wind farm closest to you. .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... What is the difference between a horizontal-axis and a vertical-axis windmill? Include a picture in the right. .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... Your neighbor wants to put a horizontal axis windmill on his roof (or on top of the building he lives in) for a horizontal windmill which has a 10 foot wing-span. Draft a letter of support or a letter of opposition below. Be sure to justify your choice. .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... .................................................................................................................................................................................................... 4
