5 energy c02 powerpoint slides

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What is the difference

between heat and temperature?

Questions to think about…

What is heat?

Why do things become hot or

cold?

What are the effects of heat gain and heat

loss on matter?

What are the effects of expansion and contraction in our

daily lives?

What are good and poor conductors of

heat?

What is temperature?


What is heat?• Heat is a form of energy that makes things

warm.• Things that give out heat are known as

sources of heat.• Burning fuels such as wood and gas

produces heat.• Electrical appliances like electric irons,

water heaters and electric ovens are also sources of heat.


What is heat?

• The Sun is our main source of heat.• It keeps the Earth and living things on Earth warm.


• Temperature is how hot or cold something is.• Temperature is measured in degree Celsius (°C).• Thermometers:

– These are used to measure temperature. – Thermometers usually have a liquid inside the

bulb. The level of the liquid rises or falls according to temperature changes.


bulbA thermometer



• There are different types of thermometers for different purposes.

A clinical thermometer such as the one above is used to measure temperatures a few degrees below or above the body temperature of 37°C.

placed under armpit or tongue

A digital thermometer like the one on the right can measure the temperature of our surroundings.

A laboratory thermometer is used to measure temperature in Science experiments.



• Heat sensor and datalogger– A heat sensor can be connected to a datalogger.

These can be used to measure temperature.

heat sensordatalogger


Reading a thermometer

• Reading temperature on a thermometer – how to read correctly:– Step 1: Hold the thermometer upright.– Step 2: Look at the level of the liquid.– Step 3: Position your eyes at the same level as

the liquid in the thermometer (see the next slide).– Step 4: Read the marking nearest to the level of

the liquid in the thermometer.


Reading a thermometer

• Reading temperature on a thermometer – how to read correctly:


What is the difference between heat and temperature?

• The difference between heat and temperature:

Beaker A

60°C 30°C

Beakers A and B have the same amount of water. But the water in beaker A has a higher temperature than the water in beaker B.

To heat up the same amount of water to a higher temperature, more heat is needed. Thus, the water in beaker A has more heat than the water in beaker B.

Beaker B


What is the difference between heat and temperature?

• The difference between heat and temperature:

80°C 80°C

Beaker C has more water than beaker D. The water in beakers C and D is at 80°C.

However, there is more heat in beaker C than in beaker D since more heat is needed to warm up a greater amount of water.

Beaker C Beaker D


Why do things become hot or cold?

• Things become hotter when they gain heat.• Things become colder when they lose heat.• Heat travels from a hotter place to a colder place until

both places reach the same temperature.


Why do things become hot or cold?

The mug is gaining heat from the hot

chocolate. This will cause the

temperature of the mug to rise.

The noodles is losing heat to the

surroundings, which will cause the temperature of the noodles to fall.


What are the effects of heat gain and heat loss on matter?


Change in state of water

• Water gains heat and changes from a liquid to a gas (water vapour) when heated.

• Water vapour loses heat and changes back to a liquid when cooled.

Water droplets


Expansion and contraction of a solid

• A solid expands when it gains heat.• A solid contracts when it loses heat.


Expansion and contraction of a liquid

• A liquid expands when it gains heat.• A liquid contracts when it loses heat.

A flask of coloured water is placed in hot water

A flask of coloured water is placed in cold water


Expansion and contraction of a gas

• A gas expands when it gains heat.• A gas contracts when it loses heat.

A balloon is placed over the mouth of a conical flask.

In hot water In cold water


Why are the wires hung

loosely?

What are the effects of expansion and contraction in our daily lives?

Why are gaps left in

the pavement?


What are good and poor conductors of heat?

• Metals allow heat to flow through them easily.– They are called good conductors of heat.

• Materials like wood, plastics, rubber and air do not allow heat to flow through them easily.– They are called poor conductors of heat.