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OP31 carry out simple experiments to show the transfer of heat energy by conduction, convection and radiation; investigate conduction and convection in water
These methods of transferring heat can be demonstrated using a ball as the heat and people as the particles of the matter.
Conduction is when heat travels from one particle to another. Heat moves through solids by conduction.
Convection when liquid or gas particles take extra energy and move with that energy.
Radiation is when energy is transferred in straight lines from a source of energy to other bodies
Conduction the ball moves from person to person showing how heat energy is passed from particle to particle
Convection the ball is carried by a single person
Radiation the ball is kicked or thrown to another person
Conduction
If i gave you a glass of water, but it was plastic would you know that i lied?
When you touch and hold metals how does that feel, hot of cold ??
Conduction is when heat travels from one particle to another. Heat moves through solids by conduction.
Each particle in the solid vibrates more when it is heated, this extra vibration shake the particles next to it, thus the particles share their heat.
Each particle passes on the heat energy to the particle next to it.
An experiment to show conduction in metals
Method
Stick a thumb tack to the end of each of a number of different metal rods
Place the rods in some heated water
The pin that falls off 1st is considered to be on the metal that is the best conductor, the pin that falls off last is considered the worse conductor.
Alternative method
Place equal blocks of ice on different surfaces in the same room, different containers, see which one melts the quickest
Convection
Convection
Convection
Convection when liquid or gas particles take extra energy and move with that energy.
Convection when liquid or gas particles take extra energy and move with that energy.
In the convection experiment add the colour after the liquid has been heated for a little time
In the convection experiment add the colour after the liquid has been heated for a little time
In Liquids and gases the major method of transfer of heat is Convection. This is where the molecules move and deliver their heat energy some place else. They heat up, the molecules gain kinetic energy and the vibrate more vigorously, this makes them bigger but the mass has not changed, therefore their density goes down, therefore they float towards the top.
In Liquids and gases the major method of transfer of heat is Convection. This is where the molecules move and deliver their heat energy some place else. They heat up, the molecules gain kinetic energy and the vibrate more vigorously, this makes them bigger but the mass has not changed, therefore their density goes down, therefore they float towards the top.
to demonstrate convection in Liquids
take 2 bottles, fill one with clean cold water, fill the other with warm < 50oC water with a colour, both bottles to the brim.
Steady the warm bottle, cover the cold bottle with some thin rigid plastic or card,
Place the cold bottle on top of the warm bottle, remove the card,
secure the bottles
observe
Convection Apparatus,
only add the dye after the liquid has been heated for a while
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Radiation
Radiation
OP31c To investigate Radiation
OP31c To investigate Radiation
apparatus
2 tins, one black & one shiny,
Method
Take the 2 tins, fill them with equal amounts of water
Place them in bright light
Monitor the temperature of both tins of water over time.
Other experiment
fill both up with hot water,
monitor the cooling temperature
Black object vs shiny / white objects
Black objects absorbs heat.
Black objects absorbs heat.
White objects or shiny objects reflect heat.
what do you notice about the temperatures?
what do you notice about the temperatures?
draw a graph of the temperatures falling over time
what can you conclude ?
or use a spot light
shine it on the cans and again observe the temperatures over time.
Other exp
Glass and the sun's rays.
Glass, Thermometers.
Four sheets of glass arranged like a glasshouse.
Place one thermometer under glass and one outside.
Record temps.
Every 40 mins.
for 1 school day.
Tabulate
Graph.
Insulation
Insulation is a materials ability to keep heat from transferring,
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