Vacation Science: Hoover Dam

I was recently out in Las Vegas visiting my college roommate. My one tourism request was to see the Hoover Dam. My wish was granted and my friend and I hiked along Lake Mead all the way to the Dam. We went on the Power Plant Tour and saw the new bridge being built! It was very exciting :o)

The Power Plant Tour was excellent! We were privileged to see the generators at work as well as the massive pipes through which thousands of gallons of water flow through every day! We had excellent views of the Dam as well!! A new bridge is being built to allow the highway to bypass the Dam since the road passing over it winds through the mountains at 25 mph. The bridge was fascinating and promises to be one of the best views of the Dam!

The tour and museum were excellent educational resources. In the generator room, one of the generators was dissembled for maintenance - a phenomena that only occurs every 25 years! The rotor (the big wheel with large magnets attached all around) was just lying on the floor. It weighs almost 6 tons and took two huge cranes to move it from its normal location.

The museum also did an excellent job of explaining how the generators work! I have included pictures below to help explain:

This is a scale model of a generator. The water flows in the clear tube into the small dark green squares. These channels are openned and closed depending on the amount of water to be let in. As the water spins (sort of like a horizontal water wheel), the metal rod you can see in the middle of the picture begins to spin (this is the shaft). The shaft is connected to the rotor (the round part at the top which appears to have silver Lady Finger cookies attached) and the rotor spins as well. 

Surrounding the rotor is coils of copper wire. From Physics, we know that when we pass a magnet through a coil of copper wire (known as a solenoid) the magnet field changes. And where there's a changing magnetic field, there's current flowing.

So...to sum it up, the water makes the shaft and rotor turn, which causes the magnets to move past the coils of copper wire, causing a changing magnetic field, resulting in a current, or flow of electricity.

To top it all off -- the Hoover Dam wasn't even built to serve this purpose. It was created to aid farmers in irrigation and creating hydroelectricity was the only way to pay off such a massive project built during the Depression!!

I am seriously considering teaching Electricity & Magnetism units using the Hoover Dam so students can understand the real life applications!