Find out the rate of which heat transfer happens.

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Science Investigation: Insulation

Science Investigation: Insulation

Introduction

My investigation is to find out the rate of which heat transfer happens. Heat transfer is a process in which energy in the form of heat energy is exchanged between materials that are at a different temperature. Heat is generally transferred by conduction, convection, radiation and evaporation. All of these processes can all happen simultaneously but it is likely that one will give the greater heat exchange. Heat is exchanged through the brick wall by conduction. The surfaces of a high-speed aircraft are heated up by convection. The earth is heated by heat that is being radiated from the sun.

These experiments involved the temperature of hot water being recorded at chosen intervals in a copper can.

Here is a description of the following processes that will affect my experiment:

Conduction

This is where heat energy passes through the walls of the can by making the particles of the can vibrate and then they will make the particles next to them vibrate causing the heat to pass through the walls of the can and out to the surroundings. Materials that are good thermal conductors tend to be good electrical conductors; metals such as gold, silver and copper have high thermal conductivity's and will conduct heat readily. Materials such as glass have much smaller heat transfer values and are poor heat conductors.

Convection

This is where the cooler water particles sink down to the bottom and the warmer water particles float up to the top. Convection will only affect my experiment if I did not have a lid. This is because the warm water will float up to the top and the heat energy will escape out of the top. If a pan of water was being heated from below then the water particles at the bottom of the pan will become warm as therefore become less dense, they will begin to rise to the top of the pan. As the warmer water particles begin to rise, the cooler water particles at the top of the pan will sink to the bottom, as they are less dense. Once at the bottom of the pan the will start to get warmer and become less dense. This process will continue until the pan of water is at the same temperature.

Radiation

This is when the warm water particles vibrate the water particles next to them. This will give them more energy and will make the water there warmer. The water particles at the top of the can will radiate the heat energy into the surrounding air. For heat to radiate it does not need to be in contact with matter. Heat can radiate for some thing to another body through a complete vacuum, this is how the sun heats up the earth. This process can also be called the Wave Motion.
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Evaporation

This could cool down the water, as when the water evaporates it will take the heat away with it in the same way evaporating sweat cools down our bodies. If I use a lid this could slow down this process. As the water vapour will not be able to escape into the air as quickly as it would normally keeping the heat in for longer.

If I insulate the can with different materials then it will slow down the heat loss, but I cannot stop it. This will be useful for keeping drinks hot.

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