3 1 energy (physical sciences)

Students know energy comes from the Sun to Earth in the form of light.. Students know sources of stored energy take many forms, such as food, fuel, and batteries.. Students know machi

Genre Comprehension Skill Text Features Science Content

Nonfi ction Main Idea and Details • Captions

• Chart

• Diagram

• Glossary

Forms and Properties of Energy

Scott Foresman Science 3.1

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Standard Set 1 Physical Sciences

1 Energy and matter have multiple

forms and can be changed from

one form to another As a basis for

understanding this concept:

1.a. Students know energy comes from

the Sun to Earth in the form of light.

1.b. Students know sources of stored

energy take many forms, such as food,

fuel, and batteries.

1.c. Students know machines and

living things convert stored energy to motion and heat.

1.d Students know energy can be

carried from one place to another by waves, such as water waves and sound waves, by electric current, and by moving objects

ISBN 0-328-23517-2 ì<(sk$m)=cdfbhj< +^-Ä-U-Ä-U

by Trish West

Physical Sciences

Picture Credits

Illustrations

3, 16 Tony Randazzo; 11, 13 Jeff Mangiat.

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ISBN: 0-328-23517-2

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1 2 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06

Vocabulary

compression wave

electricity

energy

energy of motion

friction

stored energy

by Trish West

What are sources

of energy?

Energy

Energy is the ability to do work The energy

you use to work makes things move Most of

Earth’s energy comes from the Sun It comes to us

as light energy Plants use it to live and grow

Stored Energy

Food has stored energy This energy can

change into a form that can do work Energy is

stored in batteries and fuels Batteries and fuels

change stored energy into motion, light, and heat

Your body gains stored energy whenever you eat.

3

Energy Stored in Batteries

The wires inside a fl ashlight connect its battery

to a small bulb Turning on the fl ashlight changes chemicals inside the battery This releases stored energy Energy moves through the wires to the bulb There it changes to light energy The bulb gives off light

A fl ashlight battery can only store a small amount of energy The bulb will not glow if the energy in the battery has been used up

The fl ashlight battery’s chemicals are stored energy

Turning the fl ashlight on changes them to light.

Energy from Fuel

Coal, oil, natural gas, and gasoline are fuels

Their chemicals change as they burn Their stored

energy becomes heat energy and light energy

If you strike a match, its chemicals burn Their

stored energy changes into heat and light

Natural gas has stored energy Its stored energy

changes into heat energy as it burns This heat

energy cooks food and warms the air

Fuels such as natural gas give us light and heat The

stored energy in matches also gives us light and heat.

5

Energy from Food

You need energy to be strong and healthy

That energy comes from food Chemical changes

in your body break down the food you eat The food’s stored energy is released Your body uses this energy to grow, stay warm, work, and play

Your muscles change some of this energy into motion Then you can run and kick a ball Some

of the energy from food becomes heat Heat energy keeps your body warm

Your body uses stored energy while you play.

What are some

ways that energy

changes form?

Changing Forms of Energy

Energy changes forms all the time These

changes happen in living and nonliving things

Moving objects have a kind of energy called

energy of motion The faster an object moves,

the more energy of motion it has

Machines change energy from one form to

another A car engine changes the stored energy

in gasoline The stored energy becomes energy of

motion Energy of motion turns the car’s wheels

Animals, cable cars, and toys change

energy into energy of motion.

7

Forms of Energy

Chemical Chemical energy is found in food

Eating food changes its stored energy

It becomes energy you can use.

Motion Motion energy is the energy of moving things Moving parts in machines have this energy.

Electrical Electrical energy passes through wires made of a special metal It runs machines such as TVs.

Light Light energy comes from the Sun

Plants use light energy to make food.

Thermal Thermal energy is felt as heat Matter moves faster when its heated

Transfer of Motion

Energy of motion is transferred, or passed along

Think of rolling a ball toward another ball The

rolling ball might hit the other ball It might slow

down and stop But its energy would not go away

Some of it would transfer to the other ball

The other ball, with its new energy of motion,

might move

Energy is always changing forms But it is never

lost The total amount of energy never changes

The ball on the far right will transfer its energy of motion to the other balls.

9

Motion and Heat

When objects hit, some energy of motion changes into heat energy This happens because

of friction Friction is a force caused by rubbing

It slows down the energy of motion It can cause moving objects to slow down or even stop But it does not cause energy to be lost The amount of energy stays the same

Friction is produced by the race car’s spinning wheels.

What are some

ways energy moves?

Water Waves

Water waves can be small, like ripples in a

bucket of water Waves can also be huge, like

those formed by ocean storms A water wave’s size

depends on how much energy it carries

Water waves move up and down But the water

stays in about the same place Energy travels

forward through the water

Energy is moved through

water by waves.

Making Waves

The tub below was fi lled with water to show how water waves transfer energy Two balls were placed in the tub Then one end of the tub was lifted and put down A wave spread through the water The wave moved past the balls The balls moved up and down But they stayed in about the same place

The waves move the balls up and down, but not forward.

Sound Waves

The energy of air moving back and forth can

make sounds When a bell rings, it moves back and

forth very quickly It pushes air particles together

Then the particles spread apart This movement

forms a compression wave Sounds waves are

compression waves

Transfer of Sound Energy

Sound waves from the saxophone travel from

the instrument to your ear They make your

eardrum vibrate when they hit it The waves transfer

sound energy from the saxophone to your ear

Vibrations from the

saxophone produce

compression waves.

13

Hearing Sound

Your eardrum stretches across your ear’s inside

It is thin and skin-like Vibrations of the eardrum travel along bones They move to other parts inside the ear They travel to your brain as signals The signals help your brain fi gure out what you heard

Compression waves from the saxophone cause the eardrum

to vibrate.

Eardrum

Parts of Earth’s crust can move suddenly These

movements, called earthquakes, send energy waves

in all directions Energy waves make the ground

vibrate They can crack the ground and make

buildings fall

An earthquake’s energy waves damaged

this road in Oakland, California

Earthquake Waves

An earthquake causes three kinds of waves

One kind is like a sound wave These waves push the ground in the direction they are traveling The ground then moves back Another kind is like a wave of water It shakes the ground up and down

The third kind shakes the ground from side to side

Earthquake waves are strongest at the point where the earthquake starts They lose strength as they move away

This parking garage nearly collapsed during a 1994 earthquake.

Where does electricity

come from?

Electrical Energy

Electricity is a form of energy that can fl ow

as a charge through a wire It is made at a power

plant It is made using energy from water, wind,

the Sun, and fossil fuels It is also made using

nuclear energy Electricity is changed into energy of

heat, light, or motion when it reaches your home

This diagram shows the wires that carry

electricity to peoples’ homes

16

Transmission Wires

Power Destination

17

Sources of Electricity

Many things in your home run on electrical energy This electrical energy comes from different sources The energy of moving water is changed into electricity So is the heat energy of burning fuel The heat from special fuel at a nuclear power station is also changed into electricity Electrical energy can come from the energy in wind and sunlight too

San Francisco’s subway cars use electrical energy to move.

This power plant burns natural gas to make heat energy The heat energy is changed into electricity.

Moving water produces energy

of motion The power station changes the energy into electricity.

19

Windmills change wind energy into electricity These windmills are found near Livermore, California.

This power station uses nuclear

energy to make heat energy The heat energy is changed into electricity.

compression wave a wave that carries energy

by squeezing particles together and then letting them spread apart

electricity electrical energy that moves

through wires

ability to make things move, stretch, or grow; or cause change

energy of motion the energy carried by

moving objects

motion into heat energy

stored energy energy in food, fuel, and

batteries that can be changed to motion, light,

or heat

Glossary What did you learn?

1 Where does most of Earth’s energy come from?

2 What makes a fl ashlight’s bulb glow?

3 When a fuel burns, what does its stored energy change

into?

energy Write a topic sentence that describes what energy is Then add sentences that tell about two kinds

of energy.

page 9? What details support it?