To compare the cooling rate of water in an insulated and non-insulated container.

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Physics coursework

Aim: -

        To compare the cooling rate of water in an insulated and non-insulated container.

Predications: -

Qualitative

        As time passes the temperature of the water falls.

Quantitative

        The passage of time and the temperature of the water vary inversely proportionally i.e. as the time gets greater the temperature of the water gets less and they vary at an equal rate.

        I also predict that the rate of cooling will be less for the water when at lower temperature therefore the rate of cooling for the insulated calorimeter is greater than for the non-insulated calorimeter.

Theory: -

Since the water is hot more energy is given to the copper calorimeter particles, so when the copper particles collide with the air particles, the copper particles have more energy, the energy is passed to the air particles. When the energy is given to the air particles, it is given as heat; therefore the water particles lose energy to the air, which makes the temperature of the water decrease rapidly. The water particles keep losing the energy to the copper particles & the copper particles keep losing the energy to the air particles, until the air particles contain more energy than the water & copper particles. At this point only a few water particles have got more energy then the air particles. Therefore the water temperature decreases slowly. This happens until the system has reached equilibrium and then keeps it at a certain temperature.

        In the experiment we will use bubble wrap as insulation, the bubble wrap will reduce the heat loss, as it isn’t a conductor. The bubble warp would be a good insulator because it has air trapped in it (Even though some heat will escape through the plastic, it will reduce heat loss dramatically). The heat loss will not radiate away unless the colour of the bubble wrap is shiny, shiny surfaces are poor absorbers of radiation, the radiation is reflected back. Dark & dull surfaces are good at absorbing & emitting radiation. Radiation travels as energy. I have to make sure I cover the top part of the calorimeter, so no water vapor & water particles can escape, through convection, because hot material rises since it is less dense & cool material falls since it is denser. The air around the calorimeter will absorb the energy, but it won’t do it quickly because the air particles are set out far apart & don’t have bonds in between them. So the particles don’t collide much, therefore the heat doesn’t pass across quickly. Conduction basically works because the particles are closely set and there are bonds in between them.  The particles (solid) are tightly packed together, so they collide more. When they collide, the energy is passed.  The more energy is passed, the more heat is given. The bonds in solids, help in the conduction state, because the bonds push/pull on the particles so they collide more frequently. This means that more energy is given, which means the heat can be passed on quickly.

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        Air is an insulator.  Air is an insulator because the particles are too far apart and don’t have bonds in between them. The particles are set out far apart, so they don’t collide as much. This means that they can’t pass the energy.  Which means they stop conduction.  There is also some help in metals, because they have free electrons that carry the energy as they move between particles.

Diagram of experiment: -

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