HEAT

What do you think thisphotograph shows?

ENERGY of HEATIt takes heat to shape glass or to

make a cup of tea.

Temperature measures how hot or

cold something is.

Energy moves between objects that

have different temperatures.

HEAT is energy that moves between

objects of different temperatures.

The difference in temperatures makes

the energy move back and forth.

Temperature is

measured in

different scales.

The two scales on

this thermometer are

CELSIUS

and

FAHRENHEIT.

Clothing traps heat near our body.

Water coming from a shower head is hotter than the air

around it.

Ice cubes melt as heat transfers to them from the

warm air.

Heat moves from the burner to the pan, to the water, and

then to vapor, to the air.

This is dry ice – frozen carbon dioxide.

It is about -80 degrees Celsius /

-112 degrees Fahrenheit

HEAT

on the

MOVE

Heat moves from your hand to the

snow and the snow melts.

Your hand feels cold.

Heat is CONDUCTED from the soup

to the spoon.

Soon the spoon feels hot.

CONDUCTIONConduction is the transfer or

movement of heat between two objects

that are touching.

Conduction can also occur within an

object. Heat moves from inside your body

to warm your skin.

Your feet and hands stay warm because

heat is moving all around your body.

CONVECTIONConvection is the transfer of heat

within a liquid or a gas.

Particles in liquids and gases move

more easily because they are farther

apart.

The particles take heat with them.

Heat from a campfire warms the air

around it by convection.

Hot air rises above the cooler air in the balloon.

That’s what keeps a hot-air balloon in flight.

Heat is conducted from the burner to

the pot and then to the water.Heated water travels up, warming

the cool water above.Cooler water sinks to the bottom,

where it gets heated.The cycle repeats – this is called

CONVECTION CURRENT.

FEELING RADIANT

Heat moves by conduction

between solids that are

touching.

Heat moves by convection

through gases and liquids.

Heat can also move as

RADIATION.

Radiation is the transfer of heat without matter to carry it.

Heat leaves one object and goes instantly to another.

Standing near a campfire

you feel the warm air, you

also feel the heat through

radiation.

Heat from the sun radiates through

space and through the atmosphere

before it warms your face.

Heat radiating from this light

keeps these chick eggs warm.

RADIATION is the transfer of heat

without matter to carry it.

Heat leaves one object and is

transferred on to the other.

Radiation is the most important way

heat can move.

Life on Earth needs heat from the sun.

But space is a vacuum.

How does heat travel through the

emptiness of space?

by RADIATION!

Heat moves through some

materials very easily.

Heat from an oven moves easily into

a pan. But heat from the pan did

not pass through the oven mitt.

A material that allows heat to

move through it easily is called a

conductor. Many heat conductors

also conduct electricity well.

Glass does not conduct heat well.

If you pour boiling water into a

metal bowl the outside of the bowl

quickly gets hot. A glass bowl

gets warm more slowly.

Boiling water

in glass cup.

Boiling water in

metal pot.

Marble or stone does not conduct

heat as well as metals do. But it

can still conduct heat away from

your body. That’s why marble

feels cool when you touch it.

Metals are great heat conductors.

Some metals conduct heat better

than others do.

For the most part, solids are better

conductors of heat than liquids or

gases are. That’s because the

particles that make up a solid are

packed closely together. They vibrate,

but they don’t move apart very

much. Heat can move quickly form

one particle to another.

Look carefully at this experiment.

What happened? Why?

Particles in the hot coffee have higher kinetic energy which transmits heat to the cup and ultimately to the air

surrounding the cup.

But not all materials are conductors.

Heat does not move easily through

some materials.

And it does not move at all through

other materials.

Materials that do not conduct

heat well are called

INSULATORS.

Oven mitts are insulators.

They are made of materials that are

poor conductors of heat. When you

remove a pan of cookies from the

oven, your hands don’t get burned.

Gases can be good insulators. A thin

layer of trapped air is an excellent

insulator. In cold weather, layers of

clothing trap your body heat near

you. There is air between the layers

of clothing. Along with the clothing,

the air insulates your body.

Insulators can be used to slow

down the movement of heat. Metal

wires conduct electricity and heat.

Most wires are covered in rubber

to insulate them and keep people

safe from the electricity and heat.

Hair is an Insulator

Most furry animals stay warm in

cold weather. Fur is made of thick

hairs. Around each hair is air. The

air and the fur act as insulators,

keeping the animals warm.

How does a thermos work?

A thermos has a glass lining.

This glass lining holds the cocoa or soup.

Glass is not a good conductor of heat.

Energy can even move in a vacuum. Using

a reflective silver surface act like a mirror.

It reflects some heat back.

There is a vacuum between the inner and outer

glass layers of the thermos bottle. The vacuum

keeps conduction or convection from taking

place. Using this system reduces conduction,

convection, and radiation.

The cocoa stays hot.

How can knowledge of insulation

help us conserve energy?

When the weather is hot,

you want to keep heat

from coming into your

home. When the

weather is cold,

you want to keep heat

from leaving your home.

It costs money to cool

and heat a home. Heat leavingthe home

There are different ways to slow the

flow of heat into or out of a house.

Some things need to be done while

the house is being built.

Others things can be done to an

existing home.

Insulating a home saves money.

It also helps conserve energy.

The number 1 thing that can be done

to conserve energy is insulation.

Insulation is blown inside the walls

of a house. Insulation keeps heat

from traveling through to the attic.

Insulation keeps heat from escaping

through the walls.

The next thing that you can use

to conserve energy is windows.

New windows have two

panes of glass to limit conduction.

They also have a special coating

that limits heat radiation.

Insulating pipes is another way to

conserve energy. Hot pipes radiate

heat from water into the air.

Wrapping the pipes keeps the

heat from escaping.

Soil is a great insulator.

Basements are usually cool, even

in the summer because soil covers

the sides of basement walls.

REVIEWWORD BANK – WORDS MAY BE USED MORE THAN ONCE

insulator conductor conduction convection radiation

Heat moves easily through it: _______________________________

Heat does not move easily through it: ________________________

Solids often do this to heat: ________________________________

A thin layer of trapped air can do this to heat: _________________

Which forms of heat transfer do insulated bottles prevent: ______

______________________________________________________

Wrapping hot water pipes prevent which form of heat transfer: ___

______________________________________________________

REVIEWWORD BANK - CONDUCTION CONVECTION RADIATION

Add hot water to bath ____________________________________

Space heater ____________________________________________

Iron-on decals ___________________________________________

Clothes dryer ____________________________________________

Sunlight through window _________________________________

Sandwich press __________________________________________