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Activity
1. Rub your hands quickly against each other.
2. Then quickly place them onto your face.
3. Describe what you feel.
Your hands feel warm.
4. Why does it feel warm?
It feels warm as HEAT has been generated when we rubbed our hands together.
HEAT
Heat is a form of energy. Our main source of
HEAT on earth is the
SUN.
What are some sources of Heat?
Natural Sources Electrical Appliances Burning fuels like…
Volcanoes
Geysers
Lava from inside
the Earth.
Electric Iron
Light Bulb
Rice Cooker
Hair Dryer
Wood
Gas
Charcoal
Candle Wax
Petrol
Temperature is the measure of how hot or cold an object is.
Some HEAT sources are also sources of LIGHT. Eg. The
Light Bulb, It gives off both Heat & Light.
What are some Heat sources that are also Light sources?
Temperature is the measure of how hot or
cold an object is.
Temperature
An object that has a HIGHtemperature feels ______. An object that has a LOWtemperature feels ______.
hot
cold
The common units for temperature is
degree Celsius.
OC
Thermometers are used to give an accurate reading of temperature.
Thermometers come in many different types for different uses. For eg.
1. Laboratory Thermometers
2. Digital Thermometers
3. Pyrometers
Laboratory Thermometers
The temperature is
shown by the marking on
the thermometer which is
nearest to the mercury
level.
Are normally filled with
mercury or alcohol.
Laboratory thermometers
are used in the lab to
conduct experiments.
TemperatureHEAT
Differences
1. Is a form of energy.
2. Cannot be measured with a thermometer.
1. Is a measure of how hot or cold an object is.
2. Can be measured with a thermometer.
Heat Flows and Changes in Temperature
Basin filled with Warm Water
Cold can of Coke
What would happen to the can of Coke after it is
placed in the basin for a while?
The Coke can will slowly warm up until it
is the sametemperature as the water in the basin.
This is because it has gained heat from the
warm water.
Heat will always flow from the hotterobject to the colder object, until both
reach the same temperature.
Basin filled with crushed Ice.
Glass beaker filled with
hot coffee.
What would happen to the coffee in the beaker after it
is placed in the basin for a while?
Can you draw the arrows to show the flow of heat?
The coffee will slowly cool down until it is the same temperature as the ice in the basin.
This is as the coffee has lost heat to the ice.
When objects GAIN heat, they:
Increase in temperature.
Catch fire.
Change from solid to liquid. Eg. Ice melting.
Change from liquid to gas. Eg. Water boiling or evaporating.
Expand (Get Bigger, Increase in SIZE).
When objects Lose heat, they:
Decrease in temperature.
Change from gas to liquid. Eg. Condensation.
Change from liquid to solid. Eg. Water freezing to form ice.
Contract (Get smaller, Decrease in SIZE).
Beaker
Bunsen Burner
Boiling Water
Ice Cube
Good and bad conductors of Heat. (1)
Take a look at the experiment setup at the top of the page in your Text
Pg 129. Which of the candles will fall off first? Which will fall last?
What has happened: Heat has been conductedfrom the flame to the candles through the metal rod.
The candle that receives the conducted heat first will start to melt first.
Good and bad conductors of Heat (2).
Take a look at the experiment setup in your Text Pg 130. Which of the
toothpicks will fall off first? Which was the best conductor of heat?
What has happened: The metal rod is the bestconductor of Heat, it conducts heat fastest, so Toothpick A
will be the fastest to drop.
Air is the worst conductor, it conducts heat slowest, so
Toothpick C will drop last.
Good Conductors
SteelCopper
Iron
Tin Aluminium
Some examples of Good & Bad conductors.
Bad Conductors
PlasticWood
Clay
Glass