LALALA; physics! :D

Physics

Chapter 8.5 - Applications of Thermal Energy Transfer

Uses of good conductors of heat

1) Cooking Utensils

Imagine, your cooking pot is made out of wood/plastic, its gonna take a billion years for your food to get cooked. That is why our cooking pots, saucepans are made out of metal, this is to ensure direct heating is involved.

2) Soldering iron rods

the tip is made out of copper as copper is a better conductor of heat then iron.

3) Heat exchangers
helps save energy, mostly used in large laundry facility.

Uses of bad conductors of heat (aka insulators)
1) Handles of appliances & utensils

do you notice that your cooking pots, saucepans, kettles have handles that are made out of plastic? this is because plastic are insulators & it will prevent us from burning our hands! :D

2) Table mats

they are made out of cork so that your super hot kitchenware can be placed on the table mats without damaging your beautiful table.

3) wooden ladles

extremely useful for stirring your soup or scooping up rice.

Common applications of convection

i remember we learnt something from geography about convection!

1) Convection currents in the mantle

remember to click to enlarge! & paiseh, i scan until like that. hhahas

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2) Sea & Land Breezes

YAY! physics & geography can relate! :D :D :D

3) Radiator

Common applications of radiation

1) Teapot

have you ever wondered why is your teapot always made out of shiny material & not dark materials? remember the 3 factors of the rate of infrared radiation? As shiny surfaces are bad absorbers of radiation, it can keep your drinks hot longer then dark surfaces (:

2) Greenhouse

infrared radiation passes through the glass roof of the greenhouse & this warms up the plants & soil. When these plants & soil gets warm, they emits infrared radiation too. however, this infrared radiation is unable to pass through the glass roof as it is different from the sun's infrared radiation. the amt of infrared radiation will slowly build up, causing the temperature to rise in the greenhouse.

3) Vacuum flasks
made to minimise heat loss in 4 ways, conduction, convection, radiation & evaporation.

Stopper - is usually made out of poor conductors of heat.
Vacuum - conduction & convection is prevented by the vacuum
Silvered surface - to minimise heat loss thru radiation & it is able to reflect the radiant heat heat to the liquid, keeping the liquid warm.