Wind Energy

Wind Energy

Wind Energy	Mass in grams	Height in cm	Time in seconds	Energy in jewels	Power in watts
Playing Cards 1	8.83	76	104	65.90	0.63
Playing Cards 2	34.54	76	77	257.78	3.35
Feathers 1	7.06	76	49	52.69	1.08

1. The one of our windmills that worked the best was the playing card version (as opposed to the turkey feather version). Both of the turbines were built with a base of foam and had three blades in the foam at an angle. However, the playing card blades caught the wind better than the feather blades did. This was because the cards were uniform,rigid, and held their shape while the feathers varied in size, were easily broken, and were more flimsy. The design worked both times, but the cards were a lightweight and sturdy material, proving more efficient than the feathers.

2. The one of our classes that worked the best was the one that Miranda and Kelsey made(16.69 w). However, they did not have a picture, so I'm not sure why it worked better. The second best was made by Nate, Mike, and Evan, (10.03 w) but they also didn't have a picture. The third best was made by Jacob and Tyler(9.85w) who also didn't have a picture. (I'm sensing a pattern here.) The fourth best was made by Sofia, Jessica, and Samantha (6.5 w). Luckily, they did have a picture. Their design included slightly cupped blades that were taped to the dowel using masking tape. The blades were about six inches long and three or four inches tall. I think that the reason theirs worked better than ours was because their blades, made of cardboard, were sturdier and heavier than ours. They were all of a uniform size, kept their shape, and caught the wind easily. They were attached to the dowel in a sturdy way and were able to turn and lift weight.
3. Some limitations on our model were the size, design, and materials. Since we used playing cards and feathers for our blades, they weren't able to lift much due to their light weight. Our blades were also rather short; longer blades output more energy. The feathers especially were somewhat flimsy. Due to the work we did with them, they began to tear and not catch the wind as well. We used foam to hold the blades in place, which was not the firmest. The blades were also not all at the exact same angle of tilt, making them less efficient. The playing cards did not have any curve in them, and were only tilted, making them less aerodynamic and less functional. Since the blades were not all uniform (mainly the feathers) the wind did not catch them all the same. It would have worked better to have slightly stronger and better attached blades that were all uniform, longer, and more curved.

4. Both airplanes and windmills are affected by Bernoulli's Principle: as velocity of a fluid increases, pressure decreases. Airplanes use this change in pressure to fly; as they go faster, there is less pressure above the plane and more beneath it, creating lift so they can stay in the air. As a windmill begins to turn faster, there is less pressure beneath the blades and more above them, causing it to continue the turning motion. Much of this is due to curvature and tilting of the blades/wings, since the wind moves faster over a curved surface.

5. It is necessary to twist the rotor blades at an angle so they can catch the wind. If you have flat blades, wind blown on them will just be stopped. If the blades are at an angle, they have the opportunity to catch the wind and turn, giving off energy. Rounded or cupped blades also don't work, since the wind will fill up the blade and not move anything; tilted blades catch and spin.

6. Rotors on a windmill and the sail of a sailboat are both designed to catch the wind and move forward. A sail is tilted so when the wind catches it, the boat is moved in that direction. The blades of a windmill are tilted to catch the wind and turn in that direction. The tilt and turning factors show how windmills and sailboats operate on the same principle.