Hydroelectric Dams Yes, this is Comic Sans. I used it because I thought it would be funny. Please don’t complain about it. Question Does a higher water level behind a dam produce more electricity? Hypothesis Yes, a high water level will produce more electricity. Materials Legos, Snap Circuits voltage meter, connector wires, and water wheel, plastic tubs, waterproof caulk, and the water itself obviously. Building Process We built a dam out of legos, with a channel inside to carry water through the dam and into a Snap Circuits water wheel we placed in it. We then placed the dam into a plastic bin we cut, and sealed it with caulk. Testing Phase For testing, we filled the bin up with a pitcher to measure how much water was being poured in, and pulled out the stopper in the dam to measure electricity generated by the water wheel via a voltage meter. Our initial amount of water was 23.5 cm in height, which I then increased it to 26 cm. The dam also leaked when water was poured in, with the amount being leaked increasing as more water was introduced. Results For the 3 runs of 23.5 cm height we did, the wheel produced 0.5V. When I increased it to 26 cm, the 3 runs we did of that also produced 0.5V. We did one final run where we filled the tub to maximum height as well, which still produced 0.5V. Conclusion Our wheel has a maximum energy potential of 0.5V, due to how limited its spin speed was. However, we observed that as the water drained down closer to the top of the dam, it produced less and less electricity from that 0.5V, which supports my hypothesis. History of Dam Usage Dams have a long history of use, stretching all the way back to the Mesopotamians, who built the Jawa Dam in present-day Jordan. There are also the Romans, who built dams to divert water for drinking, bathing, and irrigation. They built the Cornalvo Dam in Spain in the 1st or 2nd Century CE, which is one of the oldest dams still in use. The early 1900s ushered in an age of dam building, with Franklin D. Roosevelt putting americans to work on building massive dam projects, the most famous of which is the Hoover Dam. Hydroelectric Dams! (General stuff) Dams can be built with water-wheels, turbines, etc. to produce electrical/mechanical power from the water flowing against the wheel/turbine, spinning it. Such mechanical power has been harnessed for a long time, used to saw planks or grind corn, wheat, or other grains in early ages. Nowadays, massive dams can be built with huge turbines for producing electricity via generators, and then connected to electrical grids to power homes. Your house could be running on hydro-power right now! However, the scale of the dam matters, so a bigger wheel and more pressurized water means more electrical/mechanical power produced. That’s why turbines today are so massive! The Science of Hydroelectric Dams! Dams work off of the kinetic energy in falling/flowing water to push a turbine, which converts that energy via a generator into electricity. This generator is, in basic terms, a reverse motor, where instead of consuming electricity to spin, it spins to produce electricity. The pressure of the water is what really matters. Bernoulli’s Principle shows us that pressure and velocity in water flow is related. The equation used is: Bernoulli’s Principle is used to show the relationship between pressure and velocity in a fluid flow. In the equation: P = Fluid Pressure V = Fluid Velocity ρ = Fluid Density g = Gravity h = Height This allows us to calculate the the velocity of the water, and thus how much it will be pushing the wheel and converting its kinetic energy into electrical power. The height of the water matters, as it is required to calculate the pressure of the water. The equation for calculating fluid pressure is: P = hρg The higher the water is, the more pressure is being applied as you go deeper into it. To calculate the pressure based on the height of the water above the turbine, you just subtract the the two water heights. This, in operation, turns the equation to: P = (h₁-h₂)ρg This means that the larger the dam and the deeper the water, the more power that can be produced.
