Forms of Energy

Energy – the ability to cause changes in matter

A moving car has energy. The race car’s engine changes the
energy stored in gasoline into movement. The car moves because
one form of energy changes into another.

A boy riding a bike has energy. The boys muscles supply the
energy to pedal the bike. Moving the pedals makes the bike
move.

A baseball player has energy. He must get energy inside his
body from the food he eats to be able to hit the ball.

A water wheel has energy. The moving water supplies
the energy to turn the water wheel.

Multiple Choice

Which of these objects best demonstrates energy?

• a car being driven

• a vase holding flowers

• a book sitting on the floor

• a balloon floating on water

Multiple Choice

Which of these is an example of energy doing work?

• a roof stopping rain

• a door staying closed

• a notebook sitting on a desk

• a loaf of bread baking in an oven

Multiple Choice

Which of the following is NOT an example of using energy to create a change?

• a fireplace burning wood for a fire

• a solar cell using light for electricity

• the gasoline in a car making the engine run

• the ink in a pen making a stain when it leaks

Multiple Choice

Which of these is NOT an example of energy causing motion?

• sitting still on a swing

• hitting a tennis ball softly

• sliding fast down a slide

• kicking a soccer ball hard

Energy comes in many forms.

Electrical charges can turn on lights, cool your

home, and allow your TV to turn on.

Electrical Energy

is the energy produced when electrons move from one place to another place. The movement of electrons is electricity.

Electrical charges can turn on lights, cool your

home, and allow your TV to turn on.

Mechanical Energy

is the energy an object has because
due to its motion or due to its position.

When work is done on an object, that object gains

energy. The energy acquired by the object on which work

is done is known as mechanical energy.

Multiple Choice

Which of the following is the best example of mechanical energy?

• a lamp that is turned on

• a ball that is hit with a bat

• wood that is burning in a fireplace

• music that is coming from a speaker

Multiple Choice

A vase with flowers is sitting on the teacher's desk. What type of energy does this vase have?

• stored thermal energy

• released thermal energy

• stored mechanical energy

• released mechanical energy

Multiple Choice

Some interactions involve more than one form of energy. Which forms of energy are produced when a hammer hits a nail?

• electrical and mechanical

• sound and mechanical

• light and sound

• chemical and mechanical

Chemical Energy

is the energy stored in materials such as

food and fuels. Chemical energy is the result

of atoms and molecules interacting.

Plants use the energy in sunlight to make food. In the process, the
sun’s light energy is changed to chemical energy. Some of the
chemical energy is stored in the plant. Animals that eat the plants
take in this chemical energy and animals that eat plant-eating animals
also take in the chemical energy. You and other animals use this
energy to stay alive.

Multiple Choice

Which example demonstrates the use of chemical energy?

• a ball landing

• a burning fire

• a magnet holding a picture on a refrigerator

• a marble sitting still at the bottom of a ramp

Heat Energy (also called thermal energy) is the energy of moving particles. Moving particles have energy.

Particles in the pot move faster then the
particles in water move faster. The more
the water particles are heated, the faster
they move.

Heat energy can be produced in
different ways. All of these ways
change another form of energy
into heat energy.

The energy of motion can produce heat energy. Heat is produced
when two objects are rubbed against each other.

Multiple Choice

Which energy form is transferred through a cup as the ice melts in a drink?

• chemical

• heat

• light

• sound

Light Energy is the energy that travels in waves.

Light travels in a straight line until it strikes and object or travels

from one material to another.

If you shine light on a
surface, some of that
light will bounce off, or
be reflected by, the
surface. This process is
called reflection.

When light passes from
one object to another,
light changes
direction slightly. This is
called refraction.

Light can be taken in by an object. This means it is absorbed. Most objects
absorb some colors of light. Only clear objects transmit the light that hits
them.

Multiple Choice

There is only one fish in the fishbowl below. When Joseph looks down at the fish, the image he observes is closer to the surface than the actual location of the fish.

  Which wave characteristic does Joseph’s observation demonstrate?

• absorb

   

• diffract

• reflect

•   refract

Multiple Choice

When a person looks into a mirror, how do light rays behave to allow the person to see the image?

• The light rays are bent by the mirror.

• The light rays are stopped by the mirror.

• The light rays are reflected by the mirror.

• The light rays are absorbed by the mirror.

Multiple Choice

For a special dinner, Catherine’s mom lit some candles in the living room for decoration. What two forms of energy does the fire from a burning candle release?

 

  

• light and heat

    

• sound and chemical

    

• magnetic and nuclear

    

• electrical and mechanical

Sound Energy

is the energy carried by sound waves which

are produced when an object vibrates.

The different vibrations that cause these sounds are carried by sound

waves with different characteristics.

The pitch of a sound is how high or low the sound is. When vibrations are short

the pitch is high. When vibrations are long, the pitch is low.

Multiple Choice

Melissa’s school rings a bell to alert students that it is time to start class. When the bell rings, it vibrates. The use of vibrations to send messages is an example of which type of energy?

• chemical

• heat

• light

• sound

Multiple Choice

When an object vibrates, causing air particles to move and vibrate, sound is produced. If the vibrations are fast, what feature of sound is heard?

• low pitch

• high pitch

• loud sound

• soft sound

Energy is the ability to do work.

In Science, work is done when a force moves an object.
Energy can cause motion. Energy can also cause
changes in matter.

Energy is a property of matter, and all matter has it.
Whenever a light bulb is lit, a turkey is roasted, an
orchestra plays, a fan spins, a book falls off the shelf,
or a fire burns, you can be sure that energy made it
happen.

Multiple Choice

Frank uses a bowling ball to demonstrate how energy can cause changes. Which of the following actions would NOT demonstrate a change caused by applying energy to the ball?

• He holds the bowling ball in both hands.

• He spins the bowling ball with one hand.

• He rolls the bowling ball across the floor.

• He lifts the bowling ball to place it on a shelf.

Multiple Choice

How does the Sun’s energy create change in plants?

• It allows the plant to breathe.

• It changes carbon dioxide and water into food.

• It changes the position of the plant.

• It gives water to the plant.

Energy can cause changes in matter.

People use electrical energy to start car engines,
run the headlights and taillights, and light buildings and
streets.

Heat energy deep below the Earth’s surface makes
a volcano erupt. The eruption can throw lava, rocks,
and ash high into the air.

Plants use the energy in sunlight to change carbon
dioxide gas and water into a simple sugar for food.

Windmills change the energy of moving air into
electrical energy. Wind turns the windmill’s blades.
The blades turn a rod that is connected to a
generator that produces electricity. But using
windmills to generate electricity only works well
in places where wind blows steadily.

Moving water has energy. Hydroelectric power plants use
turbines and generators to convert the energy or moving
water into electricity. Most hydroelectric power plants are
part of dams built across rivers. In some coastal areas, the
moving water in ocean tides is used to generate electricity
also.

Multiple Choice

Hydroelectric power creates electricity by using moving __________.

• Heat

   

• Air

• Water

    

• Light

Multiple Choice

Windmills or wind turbines use wind to create _________________.

• Heat Energy

• Light Energy

• Sound Energy

• Electrical Energy