Grade 4, Unit P.2, Heat and temperature 72 52

Physical science

Unit 4P.2: Heat and Temperature

Heat and temperature

Insulation

Science skills:

Estimating

measuring

Predicting

By the end of this unit you should know:

The difference between heat and temperature.

How to measure the temperature.

Things will either warm up or cool down to match

the temperature of their surrounding

Substances are different in their conducting and

insulating properties.

Grade 4, Unit P.2, Heat and temperature 73 52

Physical science

Make a mind map! Write as much as you know, even

draw, about the words HEAT and TEMPERATURE.

HEAT

TEMPERATURE

Grade 4, Unit P.2, Heat and temperature 74 52

Physical science

Activity: Heat and temperature

Is it hot or not?

Collect three bowls of water; fill the first one with

warm water, the second one with tap water. Fill the

last bowl with ice cold water.

Predict which bowl is the coldest. How do you know?

Test each bowl carefully with your hands. Were you

right? Put the bowls starting with the hottest.

We use our sense of touch to find out how hot our

surrounding is. You can feel the temperature of water

because the heat flows from the three bowls to your hand.

Now put one hand in the iced water, and the other

hand in the warm water, keep them there for a about

a minute. Take them out and put your both hands in

the third bowl. Discuss how you feel?

Heat is a flow of energy from warmer matter to cooler matter.

4.14.1, 4.14.2

Grade 4, Unit P.2, Heat and temperature 75 52

Physical science

We feel the heat with our hand but sometimes our senses

can be fooled!

Have you ever felt that you didn’t need a

jacket, and then when you went outside you

were wrong!

Sometimes we need to know the exact

temperature of things.

To measure the temperature accurately we use a

thermometer.

Many thermometers are made of glass tubes.

At the bottom of the tube is a wider part

called the bulb. The bulb is filled with a liquid.

Some liquids that can be used are mercury (

this is not allowed in schools as it is very

dangerous) or colored alcohol. When the bulb is

heated, the liquid in the bulb expands, or gets

larger. It rises in the glass tube. When the

bulb is cooled, the liquid contracts, or gets

smaller. It falls in the tube.

On the sides of the thermometer are a series of marks.

You read the temperature by looking at the mark on the

tube where the liquid stops.

This is a regular thermometer and

it is used in many ways

Grade 4, Unit P.2, Heat and temperature 76 52

Physical science

Temperature is usually measured on two scales. They are

the Fahrenheit scale and the Celsius scale.

Activity:

Predict the temperature of each bowl.

Check your predictions by using a

thermometer.

Record your results in the table.

How close were your estimates?

Bowl

Estimated

Temperature

What YOU

think!

Measured

temperature

Actual

temperature

Warm water

Tap water

Cold water

Measuring temperature

The temperature can be estimated using our sense of

touch. In order to measure the temperature accurately we

use the thermometer.

Temperature is a measure of how hot or cold something is.

Grade 4, Unit P.2, Heat and temperature 77 52

Physical science

Types of thermometers:

Clinical thermometers: The clinical thermometers are used

to measure the body temperature of the patient like:

Ear thermometer Underarm thermometer Oral thermometer

Food thermometers: There are many food thermometers

like:

Dial oven-safe thermometers digital instant thermometers

Outdoor thermometers: The

outdoor thermometers are used to

measure the temperature of the

surrounding air.

Grade 4, Unit P.2, Heat and temperature 78 52

Physical science

Flow of Heat

Don’t let it get cold

1. Imagine a hot dinner on a cold day. What happens to

it if you don’t eat it straight away?_____________

2. Imagine a cold drink on a hot day. What will happen

to it if you leave it for a long time before you drink

it?__________________

Does the temperature of something hot or cold change to

be more like the temperature of its surrounding?

Activity:

You will need:

3 thermometers

A bowl of iced water

A bowl of tap water

A bowl of warm water

Grade 4, Unit P.2, Heat and temperature 79 52

Physical science

Steps:

1. Firstly measure and record the temerature of the

room.

Room temperature ______________

2. Estimate and then measure the temperature of the

water in each of the three bowls. Record your

measurements.

3. What do you predict the temperature of the water in

the three bowls will be in one hour’s time? Explain your

prediction. ___________________________________

Bowl

Iced water Tap water Warm water

Estimated

temperature

Measured

temperature

Temperature

after 10 min.

Temperature

after 20 min.

Temperature

after 30 min.

4. Leave the bowls for 10 minutes. Measure the

temperatures again and after 20 minutes and 30 minutes.

Grade 4, Unit P.2, Heat and temperature 80 52

Physical science

What do you notice? Can you explain what happened?

______________________________________________

What do you notice about the temperature of the bowls

and the room?

______________________________________________

Anything that is at a different temperature from its

surrounding will change temperature over time. If left long

enough, it will either warm up or cool down to match the

temperature of all other things around it, including the air.

Both the hot dinner and the cold drink will end up at the

temperature of the surrounding air.

Grade 4, Unit P.2, Heat and temperature 81 52

Physical science

Activity

Time

Temp

Fix a thermometer

outside – decide with

your teacher where.

Measuring the

temperature during

the day and complete

the table:

Time Temperture outside

7am

9am

11am

1pm

2pm

Use the data and plot a graph. Join

the lines making a curve.

Questions:

When was the temperature

is highest during the day

(24 hours)? ____________

Why do you think it

was the highest at

that time?

_____________________

_____________________

_____________________

Grade 4, Unit P.2, Heat and temperature 82 52

Physical science

Key words:

Heat

Temperature

Thermometer

Degrees

Celsius

Fahrenheit

Surrounding

Room

temperature

Key ideas:

How hot or cold something is, is

called temperature.

We can measure the

temperature using a

thermometer.

Heat, a flow of energy from

warmer matter to cooler matter.

Over time, every material will

become the same temperature as

its surrounding.

Key questions:

1. What is the difference between heat and

temperature? --------------------------------------------------------------

--------------------------------------------------------------

--------------------------------------------------------------

2. Explain why energy flows from the outside air into the

inside of a refrigerator. -----------------------------------------------------------------------------

-----------------------------------------------------------------------------

--------------------------------------------------------------------------

Grade 4, Unit P.2, Heat and temperature 83 52

Physical science

3. Look at the following picture below. What will happen

to the temperature after (1) hour? The temperature of

the juice will be:

a) The same temperature

b) The room temperature

c) Increased over time

4. Look at the thermometer. Write the temperature it

shows in °C.

20°C

Grade 4, Unit P.2, Heat and temperature 84 52

Physical science

Insulation

All cups have hot liquid in it. Which cup would you prefer

to hold? And why? Discuss. Think carefully about this one!

Materials that allow heat to pass through them easily are

called thermal conductors.

Metals and glass are good thermal conductors.

Some materials do not conduct heat well. They are called

thermal insulators.

Materials such as plastics, wood, wool and air are good

thermal insulators.

4.14.3

Grade 4, Unit P.2, Heat and temperature 85 52

Physical science

Thermal insulator

A thermal insulator is a material that does not allow heat

to travel through it easily.

Which of these spoons do you think will be a good thermal

insulator?

Metal spoon Wooden spoon Plastic spoon

A saucepan of hot water

Think…

What does the handle of each spoon feel like when

they have been standing in the hot water for 10 minutes?

Grade 4, Unit P.2, Heat and temperature 86 52

Physical science

Activity

You will need

Three cups made from different materials (plastic-glass-

metal), thermometers, and hot water.

Steps:

1. Fill the cups with hot water.

2. Measure the temperature of the cups.

3. After 15 minutes measure the temperature again.

4. Record your results what do you observe

Cup

Plastic Glass Metal

Temperature

Temperature after

15 minutes

Which material would you choose for a cup of tea? Why?

_____________________________________________

Insulation Activity

You will need:

3 identical cups (with covers).

kettle (for boiling water – your teacher will pour the

hot water for you),

3 thermometers,

3 different types of materials (bubble wrap, foil,

paper, elastic bands).

Grade 4, Unit P.2, Heat and temperature 87 52

Physical science

What do you need to keep the same? In order to make it

a FAIR test

___________________________________

Wrap each cup with ONE of the materials, use elastic

bands to help you.Put the lid, on make sure you have a

hole to put the thermometer through. Record the temp

every minute for 13min.

Material Time (mins)

Foil

Paper

Bubble

Wrap

This is the same experiment as

yours. Here they are using

metal cups and digital

thermometers, you can see the

different insulation they are

using.

Grade 4, Unit P.2, Heat and temperature 88 52

Physical science

Think about it?

Five glasses containing water at 60˚C were each wrapped

in a different material. After 10 minutes, the water

temperature in each glass was recorded. The results are

shown in the table below.

Which material would you choose to wrap around a water

pipe in winter to stop the water from freezing? Explain

why? ______________________________________________________________

Some materials conduct heat very well.

Saucepans are made from

metals: they heat up

quickly. However the

handles are usually made

from another material

Such as plastic or wood,

because they are

insulators.

Think of a metal spoon

that has been left in a

steaming cup of coffee-it

gets very hot! Metals are

materials that conducts

heat well.

Grade 4, Unit P.2, Heat and temperature 89 52

Physical science

Project:

What’s the problem with getting ice-cream home

from the shops in the summer? Yes, it nearly

always starts melting before you can get to the

freezer.

Your challenge is to design some kind of packaging or bag

that will keep ice-cream cold for enough time to get home

from the shops. You will make your design in school.

What I will need:

_____________________ _____________________

_____________________ _____________________

_____________________ _____________________

What I will do:

_____________________________________________

_____________________________________________

_____________________________________________

Why I think it will work:

_____________________________________________

_____________________________________________

____________________________________________

Explain why some materials keep foods cool and

others don’t.

__________________________________________

__________________________________________

______

Grade 4, Unit P.2, Heat and temperature 90 52

Physical science

Key words:

Thermal

conductor

Thermal

insulator

Conduct

Insulate

Key ideas:

Materials that allow heat to

pass through them easily are

called thermal conductors.

Materials do not conduct heat

well are called thermal

insulators.

Key questions:

1. What do we call materials that do not let heat pass

through them?

--------------------------------------------

2. Salman bought a flask. Which of these are true and

which are false?

a. The flask will only keep drinks hot. True / False

b. The flask will keep cold drinks cold. True / False

c. The flask will not keep cold drinks cool.

True / False

d. The flask will keep hot drinks hot. True / False

Grade 4, Unit P.2, Heat and temperature 91 52

Physical science

3. Sara is cooking some rice at home. She puts water

into a metal pan and places the pan on the cooker.

Why is metal a good material for the pan?

_________________________________________________

4. Look at the graph and answer these questions.

a. Which cup kept the liquid warmest? .....................

d. Which cup is the best thermal insulator? ......................

c. What do you think was the temperature of the

room? .....................