Investigating Factors that Affect Heat Loss

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Investigating Factors that Affect Heat Loss

PROBLEM

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I have been asked to investigate the link between colour and heat

loss. Does the silver or the black cup lose its heat faster?

HYPOTHESIS

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I think that the black cup will lose heat faster than the silver cup

because black absorbs heat, then releasing it out of the cup into the

surrounding air and surface, where as the silver cup will reflect the

heat back into the cup therefore keeping the water hotter for longer.

SCIENTIFIC KNOWLEDGE

Basically it is due to three factors CONDUCTION, CONVECTION and

RADIATION.

1. CONVECTION - the hot water in both cups will have convection

current in them. The hot water will rise and sink as the water begins

to cool. This means the heat energy is being passed on to the metal

cup over most of its inner surface.

2. CONDUCTION - the metal cups will get hotter as a result of the heat

energy inside the cup. The water will pass on this heat energy due to

the fact that metal is a good conductor of heat. The heat energy will

be conducted throughout the metal cup to the outer surface where it

will be transferred to the air around the cup as radiation.

3. RADIATION - hot objects (i.e. the metal cup) emit mainly INFRA-RED

radiation, and the hotter the object the more radiation it will emit.

How much radiation the object emits will depend on the surface. The

black cup had a dark matt surface and therefore will emit more

radiation. This will mean that the black cup will lose more infra-red

radiation than the silver cup (which is a poor emitter of infra-red

radiation) and as a result it will lose its heat quicker than the

silver cup over the same amount of time.

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EQUIPMENT

The equipment that I used:

· Thermometer

· Metal cups (silver and black)

· Timer

METHOD

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