 How does a windmill create energy?

 You should be able to understand the purpose of gearing in a windmill.  You should understand how electricity and magnetism are related and common applications.  You should be a able to understand how electromagnetic generator works in a windmill.  You should be able to explain how a windmill system works from wind, moving blades, gears, to electromagnetic generation, drag and finally power.

 Electromagnetism  Gears  Gear Ratio  Power  Drag  Torque

 What do you think will happen when you put a magnet through a coil? What would happen if you put the magnet through the other side of coil?  What will happen to the wire when I place it between the N and S end of a horseshoe magnet? Why did the wire move?

 Wind is generated by the uneven heating of the earths surface.  When air moves faster it creates lower pressure slower air produces higher pressure  Blades are made by causing air to move faster over a larger distance on one side than the other  Lift is created by creating pressure differences on windmill blades that causes them to spin.

 A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Note that the smaller gear is rotating faster. Although the larger gear is rotating slower its torque is greater.

 Gears are used to transmit motion and force.  An understanding of some of the terminology is needed. In a gear train we have a gear known as the driver and one known as the follower. Driver - is the gear that has the force or motion input. Follower - is the gear that results in the force or motion output.

 We often talk about a gear ratio. The gear ratio of a gear train is the number of teeth on the follower divided by the number of teeth on the driver. In the gear train above the driver has 18 teeth while the follower has 8 teeth. Therefore the gear ratio is 8/18 or 4/9. For every 4 turns of the driver the follower turns 9 times. This gear train can be used to multiply speed on a bicycle if the follower was connected to a wheel and the driver connected to the paddles.  A simple rule applies.  Low gear ratio = more speed = less force High gear ratio= less speed = more force.

- The blades in a windmill turn a shaft that turns gears. - So what do gears do?

 If you spin the small gear that has 5 teeth, with a force F and a speed s, What will be the gear ratio force and speed on the larger gear with 10 teeth?

 2) If you have a high gear ratio you will have _____ speed and _____force? (will in the blank with the correct words.

 Wind is generated by the uneven heating of the earths surface.  When air moves faster it creates lower pressure slower air produces higher pressure  Blades are made by causing air to move faster over a larger distance on one side than the other  Lift is created by creating pressure differences on windmill blades that causes them to spin.  The blades turn a shaft that turns gears

 What will happen when you place a current carrying wire near a compass?  What happens when you make a coil with a current and place it near a compass? Has it grown stronger?  What happens when I take a nail with a current caring wire around it and placed in near some iron filling? Why did that happen? What happen when you turn off the battery?

 The basic idea behind all our demo’s and an electromagnet is extremely simple: By running electric current through a wire, you can create a magnetic field. By moving a magnetic field near a wire it will create a current in that wire. You need a changing magnetic field to create a current in a wire

 You can watch the video only one time!  Only one person in your group can be the engineer so choice wisely.  Your job is to create an electromagnet! Follow the direction in the video Read your handout to know how you will be graded.

 Wind is generated by the uneven heating of the earths surface.  When air moves faster it creates lower pressure slower air produces higher pressure  Blades are made by causing air to move faster over a larger distance on one side than the other  Lift is created by creating pressure differences on windmill blades that causes them to spin.  The blades turn a shaft that turns gears  The gears turn the magnets that create a current in the wire.

 The current in the wire is brought to the PG&E Grid or battery and can be used to power other things.

 Directions: Must fill the entire page Use at least four colors Have a border around the outside of the paper  Required Elements: (may be arranged on the page in any way you Choose) Must include a description of how wind is converted to energy. Must describe in some way the following ideas, wind, energy, lift, blades, shaft, gears, electromagnetic generation Must have a graphic representation: drawing, magazine picture, or computer graphic that ties to windmill Must include a personal response to what you have learned: comment, interpretation, evaluation, society issues, etc