How the increase in clothes on a body prevents heat loss.

Authors Avatar

Physics Coursework- Heat Transfer

Planning

Introduction

In this experiment I hope to find out how the increase in clothes on a body prevents heat loss.  To put this experiment easier to make we shall use test tubes as the body and increase the number of cotton layers around it to represent the clothes.

We shall plan a strategic method to calculate the heat loss in each test tube over a certain period of time. We shall observe how fast the body decreases in temperature by recording the temperature every 30 seconds.

Safety

In this experiment we shall be working with a lot of glass therefore we have to be careful in the presence of test tubes. The thermometers are also very fragile and the mercury may be harmful if released.

Fair Test

To keep the experiment fair, we have to keep everything the same except for the one variable we alter. This will then give us accurate results and help us find out what we intend to without altering the results.

Prediction

I predict that the more layers the test tube will have around it, the less heat it will lose in a certain period of time. The heat will be lost more slowly. I shall backup my prediction with my scientific knowledge.

There are 3 ways in which heat travels: convection, conduction and radiation. Conduction mainly happens in solids where one row of particles are vibrating and then pass on to the next row making them vibrate and so on. Radiation happens when there is a hot object and a darker coloured one next to it that attracts the heat. Convection is all to do with hot air rising and colder air taking its place, they go round in a cycle.

But the theory of convection is the one used mainly in this experiment.

This diagram explains exactly what happens to the air when the water inside the test tube is hotter than the surrounding water. So when the human body is submerged in the ocean, it is hotter than the water around it. And the heat is loss to the ocean heating up the water around it.

This hot water then moves up to the surface and the colder water around that moves closer to the body where once again heat is given out heating the water and starting the cycle all over again.

However when there are layers around the body the heat loss processes becomes much harder. Again from the diagram we can see that the water that gets heated finds it hard to rise because of the layers. And therefore no cold water can replace its place and get heated. So there will be just little heat loss to the primary water and then I predict there should be no dramatic change after that.

The difference in the number of layers will determine how long it will take for the water to escape and how much water escapes in the first place. The more layers the harder it will be for the water to rise therefore the harder it will be for heat to get lost.

I predict my graph will look like the following because it’s more likely the insulated body will maintain the heat longer.

Preliminary

Join now!

In the very first lesson we had with the equipment, we worked to justify our method. This experiment helped us decide on the measurements we take and the procedure in which we carry out the experiment. It also justified the temperatures. For example we found out that we had to keep the surrounding temperature in the pot constant throughout the whole experiment. The temperature didn’t change dramatically through one experiment but we saw that sometimes we had to add or remove ice when needed.

We also found out that 30seconds were a good enough length of time to keep ...

This is a preview of the whole essay