What Energy Transformation Takes Place When Something Burns

Introduction

Students should use the resources on the Transforming Energy student esheet to help them answer questions on the student sheet. This teacher sheet provides you with some answers to the questions.

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Forms of Energy
How do scientists define energy?
They define energy as the ability to give off heat and/or do work.

What is the "law of conservation of energy"?
Energy is neither created nor destroyed.

According to the law of conservation of energy, energy that is used does not disappear. What happens to energy?
It is transformed into another type of energy.

What does it mean when we say that energy transformations are not "efficient"?
Some energy is always changed into another form; that is, not all of it is converted from one form into another. There is always a change to produce heat.

What is the difference between renewable and nonrenewable energy resources?
Renewable energy sources are replenished in [reasonable] time whereas nonrenewable energy sources are not so their supplies are limited.

Why are solar energy and wind energy considered renewable energy resources?
They are always available.

Why are petroleum, coal, and natural gas considered nonrenewable energy sources?
They are only available in short supply and we can't quickly replace the energy source that we have used.

Why is electricity considered a secondary energy source?
It is an energy carrier and we have to use another source of energy to make it.

In the United States, what is the number one energy source for making electricity?
Coal.

Is that a renewable or nonrenewable energy source?
It is nonrenewable.

What is Electricity?
What are the three basic parts to an atom?
Protons, neutrons, and electrons are the basic parts.

How is electricity created?
It is created by moving electrons from one atom to another.

What do spinning turbines in power plants do to make electricity?
In a generator, they turn coils of copper wire inside electromagnets. This causes the electrons of the copper wire to move.

Draw and label the steps that electricity takes to go from the power plant to your home.
High power transmission lines → Transformer to boost power →  Distribution wires to neighborhoods → Transformer to reduce power → Outlet → Power cord of appliance → Back to outlet → Power lines.

Converting Coal into Electricity

	Step	Types of Energy Used
1	A machine called a pulverizer grinds the coal into a fine powder.	Mechanical energy, motion energy
2	The coal powder mixes with hot air, which helps the coal burn more efficiently, and the mixture moves to the furnace	Heat energy, motion energy
3	The burning coal heats water in a boiler, creating steam.	Chemical energy, heat energy
4	Steam released from the boiler powers an engine called a turbine, transforming heat energy from burning coal into mechanical energy that spins the turbine engine.	Heat energy, mechanical energy, motion energy
5	The kinetic energy of the spinning turbine does work in a generator, a machine that turns this work into electric energy. This happens when magnets inside a copper coil in the generator spin.	Mechanical energy, motion energy, electrical energy
6	A condenser cools the steam moving through the turbine. As the steam is condensed, it turns back into water.	Motion energy, chemical energy
7	The water returns to the boiler, and the cycle begins again	Motion energy

Is all of the chemical energy stored in coal converted to electrical energy?
No.

Explain how some of the energy of coal is changed in the process generating electricity.
When coal is burned, some of the energy is changed to heat. In all of the steps where mechanical energy is used, some of the energy is always changed to heat.

This teacher sheet is a part of the Transforming Energy lesson.

What Energy Transformation Takes Place When Something Burns

Source: http://sciencenetlinks.com/student-teacher-sheets/transforming-energy-teacher-sheet/

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