Energy and Energy Resources -

Energy and Energy Resources -

Energy and Energy Resources Chapter 5 Forms of Energy What is energy?

-Energy is the ability to cause change. -Energy can cause an object to change its position or its motion. Kinetic Energy- Energy of Motion Energy due to motion is kinetic energy. The faster an object moves, the more kinetic energy it has. The kinetic energy of an object depends on its mass as well as its

speed. If two objects move at the same speed, the object with the greater mass will have more kinetic energy. Potential Energy- Stored Energy When you are holding a book, energy is stored between the book and the Earth; this type of energy is gravitational potential

energy. This type of potential energy stored between an object and the Earth depends on the weight and height of the object. When you stretch a rubber band, you are storing elastic potential energy. When you let go of the rubber band, the stored potential energy is transformed into kinetic energy.

Food has chemical potential energy, which is the energy stored in the bonds between atoms. This energy is released when chemical reactions occur. ENERGY AND WORK Work is the transfer of energy to an object by a force that makes the object move in the direction of the force.

Energy is sometimes described as the ability to do work. Other Forms of Energy Energy can be measured in joules. Mechanical energy is the total kinetic energy and potential energy in an object or group of objects. The energy carried by sound waves is sound energy. It is produced by

objects that vibrate. All materials are made of atoms and molecules that are always moving. The sum of kinetic energy and potential energy of the particles in matter due to their random motion is thermal energy. Electrical energy is the energy

carried by an electric current. Electromagnetic Waves, such as microwaves, can travel through a vacuum. The energy of electromagnetic waves is called radiant energy. NUCLEAR ENERGY is stored in the nucleus of an

atom. The Sun releases nuclear energy when the nuclei of atoms join together. Nuclear power plants release energy by splitting nuclei. Energy Transformation

A microwave oven changes electricalforms energy toof radiant energy. Changes

between energy The changes from electrical energy to radiant energy to thermal energy are energy transformations. Changes between Kinetic and Potential energy

When you throw a ball upward, the ball has its greatest speed and the most kinetic energy when it first leaves your hand. As the ball reaches its highest point, the ball gains its greatest potential energy. As the ball moves downward, potential energy decreases and kinetic energy increases.

The Law of Conservation of Energy According to the law of conservation of energy, energy can be transformed from one form into another or transferred from one region to another, but energy cannot be created or destroyed.

Friction is a force that resists the motion of one surface over another. There is always some friction between any surfaces that are in contact with each other. As you pedal a bicycle, you do work and transfer energy to the bicycle.

Because of friction between moving parts of a bicycle, some of the work you do changes to thermal energy. One way to reduce friction is to apply lubricant to surfaces that rub against each other. When you apply breaks on a bicycle, the bicycles mechanical energy is not destroyed; instead the bicycles mechanical energy is transformed into thermal energy. The total amount of energy stays

the same. USING ENERGY You use thermal energy for cooking and heating. Gas stoves and furnaces change chemical energy from natural gas into thermal energy.

During photosynthesis, plants transform radiant energy from the sun into chemical energy stored in food. Your body changes energy stored in food into kinetic energy as you move and into thermal energy, which keeps your body temperature high. A television transforms electrical energy into sound energy and into radiant energy.

Many devices you use everyday are powered by electrical energy from electrical power plants. With battery powered devices, chemical energy is transformed into electrical energy. When energy changes form, some thermal energy is always released.

Scientists often refer to this energy that cannot be used as waste energy. Cars transform most of the chemical energy in gasoline into waste energy. SOURCES OF ENERGY Most of the energy that we use every day originally came from the

sun. A small amount of energy that reaches Earths surface comes from inside Earth. Electric Power Plants Electric power plants produce most of the energy people use in their daily lives.

The three main sources of energy used in electric power plants are burning fuels, nuclear energy in Uranium, and hydroelectric power from falling water. Nonrenewable Energy Resources A nonrenewable energy resource is an energy source that is used much faster than it is replaced or is available in limited amounts.

Fossil Fuels-are the remains of ancient organisms that can be burned as an energy resource. Fossil fuels take millions of years to form, and they are being used up much faster than they can be replaced. Petroleum and natural gas form from microscope marine organisms

whose remains are subject to increasing temperature and pressure for millions of years. Coal forms on land from remains of ancient plants that come under strong pressure. Most of the coal burned in the US is used to generate electricity in power plants.

Most of the natural gas burned in the US is used to heat buildings. Burning natural gas produces less pollution than burning other fuels does. Burning fossil fuels releases substances that can mix with water in the atmosphere and form acid rain, which can damage the environment. Burning fossil fuels releases carbon dioxide, which causes global warming, a rise in Earths average temperature.

People can transform nuclear energy from Uranium nuclei into thermal energy. Uranium is a nonrenewable energy resource because it is no longer being formed inside the Earth.

Nuclear power plants do not release pollutants into the air. Nuclear power plants produce wastes that are radioactive and can cause damage to living things. RENEWABLE ENERGY SOURCES A renewable energy resource is an energy resource that is replaced as fast or faster than it is used.

In a hydroelectric power plant, the kinetic energy from falling water is converted into electrical energy. Solar energy is energy from the sun. A inexhaustible energy resource, such as solar energy, is one that cant be used up. Solar cells convert solar energy into electrical energy.

Wind is an inexhaustible energy resource that can be used to generate electricity. Thermal energy produced inside the Earth is called geothermal energy. Materials from plants and animals that people burn are called biomass.

In the USA, the most common biofuel in cars is ethanol. Conserving Energy Resources About 86% of the energy used in the USA comes from fossil fuels, a nonrenewable energy source. Conserving energy is one way to make our natural resources last longer.

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