Earth Science

WHERE DO WE GET ENERGY?

Lesson 2

​ENERGY NEEDS

• ​One of the largest uses of energy on Earth is to produce light. But energy is needed for many other uses.

​ENERGY NEEDS OVER TIME

• The need for energy resources in most areas of the world has changed over time.

• ​Early societies used some energy resources, such as wood, for light, heat, and cooking.

• Early farming - the depend on animals to pull plows and other farm equipment.

• ​In the late 1700s, people in the United States began to use industry to meet their needs. Tasks that in the past were done by people and animals were now done by machines.

​SOURCES OF ENERGY

• ​Fossil fuels - energy sources made from the remains of living organisms.

• ​Oil, natural gas, and coal

ENERGY FROM MOVING WATER

• ​Moving water can be used as an energy source. The water of moving rivers can also be used to produce electricity.

• ​Hydroelectric power, also called hydropower, is produced when dams are built across waterways.

• ​Water flows against the blades of a turbine, causing the blades to turn. The energy of the turning blades is converted to electrical energy inside a generator.

• ​Video: https://www.youtube.com/watch?v=q8HmRLCgDAI

ADVANTAGES OF

HYDROPOWER

• ​it doesn't release pollution

• ​it is renewable

DISADVANTAGES OF HYDROPOWER

• ​wildlife habitats can be destroyed when a river is dammed and the land behind the dam floods.

ENERGY FROM ATOMS AND EARTH'S HEAT

• Nuclear energy comes from the heat produced when atoms split apart. Nuclear energy is a nonrenewable resource.

• ​Nuclear energy doesn't pollute the air. But waste materials from nuclear power plants can be harmful to many organisms, including humans.

ENERGY FROM ATOMS AND EARTH'S HEAT

• The energy of the heat inside Earth is called geothermal energy.

• ​In some places, geothermal energy heats water below Earth's surface. When scientists drill into certain parts of Earth's crust, the hot water is released in the form of steam. The steam can turn turbines. Inside geothermal power plants, the turbines run generators that make electricity.

• ​Geothermal energy, a renewable resource, is more available in some areas of the world than others.

ENERGY FROM SUNLIGHT AND WIND

• ​Energy that comes from the Sun is solar energy. It can be used directly to heat homes and buildings. Solar energy can be converted to electricity without using turbines.

• ​Solar energy is renewable and does not produce pollution.

ENERGY FROM SUNLIGHT AND WIND

• Wind energy is used to turn the blades of large wind turbines, which generate electricity. Wind energy is renewable resource that does not produce pollution. The use of wind as a source of energy may not be steady or constant. Many states use wind as a source of electricity.