Potential energy is energy that is stored in an object. If you stretch a rubber band, you will give it potential energy. As the rubber band is released, potential energy is changed to motion. • Kinetic energy is energy of motion. A rubber band flying through the air has kinetic energy.
Potential Energy • A rock on top of a hill has a potential to do work. • The top of the hill is a high energy state and the bottom of the hill is a lower energy state.
Kinetic Energy • If the rock is allowed to roll down the hill, then the potential energy is converted into kinetic energy. • Kinetic energy is the energy that a moving object has.
Hydroelectric Power Using the power of water currents to generate electricity.
Hydroelectric Power Niagara Falls • http://www.pbs.org/tesla/ins/niagara.html
Advantages Inexpensive electricity Control flooding that has devastated area Disadvantages Relocate 1.5 million people Loss of ancient artifacts and archaeological sites Endangering species Dolphin, fish, birds Loss ofsediment=farmers need to use fertilizers Three Gorges Dam China
Benefits of the Three Gorges Dam • When complete, the dam will produce 85 billion kilowatt-hours of power each year. • clean power • equivalent to: • - 25 million tons of crude oil • - 50 million tons of coal • - 15 nuclear power plants • Help control flooding • In 1998, flood killed 4000 people, left 14 million people homeless, $24 billion of economic loss.
Consequences of the Three Gorges Dam • 1.5 million people need to be relocated • Reports of corruption, relocation money not getting to people but rather going to officials • 1300 archaeological sites (burial grounds, temples) will be lost • 1600 factories and mines will be submerged releasing toxins into water • Freshwater dolphin, Chinese river sturgeon, and other species pushed to extinction? • 265 billion tons of raw sewage dumped into river every year will now back up instead of going to ocean • 700 million tons of sediment is deposited by river every year, system to control this is untested, could cause collapse • 360 million people live in the Yangtze watershed, if 1/1000 chance of collapse occurs…