Technology 8th grade

Nuclear energy Nuclear energy is a clean, safe way to make electricity. It does not burn any fuel like coal so there are no pollutants released into the air. Nuclear energy is energy that is stored in the nucleus or center core of an atom. The nucleus of an atom is made of tiny particles of protons and neutrons.The electrons move around the nucleus. The nuclear energy is what holds the nucleus together.

Nuclear power plants use fission to make electricity. By splitting uranium atoms into two smaller atoms, the extra energy is released as heat. Uranium is a mineral rock, a very dense metal, that is found in the ground and is non- renewable, that means we can't make more. It is a cheap and plentiful fuel source. Power plants use the heat given off during fission as fuel to make electricity.

Ocean energy The ocean can produce two types of energy: thermal energy from the sun's heat, and mechanical energy from the tides and waves. Oceans cover more than 70% of Earth's surface, making them the world's largest solar collectors. The sun's heat warms the surface water a lot more than the deep ocean water, and this temperature difference creates thermal energy. Just a small portion of the heat trapped in the ocean could power the world.

Ocean thermal energy is used for many applications, including electricity generation. Some systems use the ocean's warm surface water to vaporize ammonia. The vapor expands and turns a turbine. The turbine then activates a generator to produce electricity.

Ocean mechanical energy is quite different from ocean thermal energy. Tides and waves are sources of energy.

HYDROELECTRIC ENERGY Hydroelectric power, or hydroelectricity, is generated by the force of falling water. (Hydro comes from the Greek word for water.) It’s one of the cleanest sources of energy, and it’s also the most reliable and costs the least. Hydroelectric energy has been in use for thousands of years. Ancient Romans built turbines, which are wheels turned by flowing water. Roman turbines were not used for electricity, but for grinding grains to make flour and breads.

The water is held behind a dam, forming an artificial lake, or reservoir. The force of the water being released from the reservoir through the dam spins the blades of a giant turbine. The turbine is connected to the generator that makes electricity as it spins. After passing through the turbine, the water flows back into the river on the other side of the dam.