How People Use Energy UNIT F CHAPTER 4

Ch 4 Lesson 1 Fossil Fuel Use Fossil fuels are fuels that formed from the remains of once-living organisms. They are: 1. Coal 2. Natural Gas 3. Petroleum Solar energy is stored as chemical energy, and it exists in all living organisms. It is mostly stored in chemical bonds.

Using Fossil Fuels Fossil fuels are the main source of energy for nations like the U.S. Fossil fuels release large amount of thermal energy when they’re burned. Natural gas, coal, or oil heat your house on cold days, and allow heat for cooking food. Petroleum is the main source of energy for transportation. Cars, trucks, buses, trains and planes all use engines that run on petroleum such as; gasoline and diesel fuel.

Alternatives to Fossil Fuels Fossil fuels are nonrenewable resources. Nonrenewable resources such as fossil fuels take million of years to form, however, they are used quickly. Scientists don’t know how limited the supply of fossil fuels are, so there are good reasons to use other sources of energy. What can we do?

Harming the Environment Burning fossil fuels releases large amounts of carbon dioxide in the air. This is a major cause of global warming. These gases become trapped in the Earth’s atmosphere and cause environmental changes.

THINK-PAIR-SHARE Review: What are the three major fossil fuels used to produce energy? 1. COAL 2. NATURAL GAS 3. PETROLEUM

THINK-PAIR-SHARE Question: Why do you think it is important to use other energy sources beside fossil fuels? Video Clip: Discovery Education: Pollution in the U.S.A.

Energy Used Around the World

K What you already know W What you want to learn L What you learned.

Electricity and Moving Water Hydroelectric Energy  “hydro” means water Electricity is generated from the force of falling water. Water wheels have been used by people for thousands of years to produce energy. During the Industrial Revolution the 1700 & 1800’s water wheels produced energy that turned machines in factories.

Hydroelectric Energy Now 1. Falling water spins a turbine.  A turbine is an improved water wheel. 2. Water strikes the blades of the turbine and makes it spin. 3. The rotating turbine than spins the shaft of an electric generator. 4. The electricity produced is than sent out over power lines.

Continued.. So where does energy in the water come from?  Remember all Earth’s energy comes originally from the sun The energy that spins a hydroelectric generators comes from the potential energy of water under pressure. Water near the surface exerts a force on the water below. The great the depth of the water, the greater the potential energy.  This is why people build dams.

Tidal Energy Tides rise and fall twice a day. In some locations the change in water height is large. When this happens, we can use the mechanical energy of moving water to produce electricity called; Tidal energy. At high tide water is held back and than falls over the turbines during low tide.

Review Questions 1. What is hydroelectric energy? 2. What is the name of a device that turn mechanical energy into electricity? 3. Why do tidal energy stations depend on large differences in water height between high and low tide? 4. Compare tidal energy with the hydroelectric energy generated by a dam. 5. Raising the level of water behind a dam improves the efficiency of a hydroelectric plant by increasing.. a) Water’s weight b) Water’s potential energy c) water’s temperature d) Water’s mass

Other Energy Sources Biomass – organic matter, such as wood, that is living or was recently alive. Advantages: Free energy source Garbage can be used Can be made into modified gasoline Disadvantages: Doesn’t release large amounts of energy

Nuclear Energy Nuclear Energy – energy release when the nucleus of an atom is split apart. Advantages: Releases large amounts of energy Disadvantages: Fuel and the waster products of nuclear reactions can be dangerous to living organisms. How it works..  Splitting nuclei releases large amounts of energy to boil water. The resulting steam is directed through turbines and electric generators. Berwick Power Plant

Wind Energy Wind Energy – wind is used to turn turbines that produce electricity. Advantages: Free Non-polluting Inexhaustible Disadvantages: Expensive Wind is inconsistent

Geothermal Energy Geothermal Energy – heat from inside the Earth. The heat comes from underground water lies close to hot magma. The water boils, steam forces its way to the surface. Then it is used to turn turbines of electric generators. Advantages: Free source of energy Disadvantages: Not available everywhere

Solar Energy Solar Energy – the energy of sunlight. Solar collectors absorb and focus the sun’s energy to heat water. Swimming pools are an example. Solar energy can also use solar cells to convert energy right into electricity. The sunlight frees electrons in flat panels. Solar panels are used to power satellites and even calculators. Advantages: Free Non-polluting Disadvantages: Expensive Sunny days are necessary

Fusion Energy Fusion Energy – release when nuclei of two small atoms are forced together. Same process occurs in the sun. The heat you feel on a sunny day is from this source. Advantages: Release large amounts of energy. Disadvantages: Extremely high temperature needed to start fusion energy. No material is known that could withstand these temperatures.

Review We will now view a video on energy sources and complete a worksheet. After the entire class views the video, you will work in groups of two to complete a worksheet. You will use the net books to go back and review the video to help answer the questions. Review Different Forms of Energy

Resources Video Earth Science: The Basics: Natural Resources and the Environment. Discovery Education. (2005). Retrieved December 3, 2009, from Discovery Education: