5 energy c02 powerpoint slides

© 2014 Marshall Cavendish International (Singapore) Pte Ltd
www.marshallcavendish.com/education

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.
What is temperature?
bulb
A 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.

5 energy c02 powerpoint slides

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5 energy c02 powerpoint slides