# Homework Help: Thermal conductivity of neoprene!

1. Dec 13, 2004

### Sophie_King

Hi,
i would appreciate any help i could get on this, thanks.
I'm stuck on part of a biomechanics assignment which is to work out the thermal conductivity of neoprene. I've done this part but am having difficulty on the following question;

"Using the value that you have obtained for thermal conductivity, estimate the heat loss from a person, immersed in water at 10ºC if A) they are wearing a 3mm wetsuit and B) if they are wearing a 5mm wetsuit"

I have the thermal conductivity of the wetsuit but i'm not sure how to work out the heat loss from that and what unit measurement to give the answer.

I'm not saying that i want the question done for me but if you think you know how to do it I'd like a few pointers!

Thanks again.

2. Dec 13, 2004

### ZapperZ

Staff Emeritus
This should have been in the Homework Zone.

You know that the rate of heat (Q) loss (or heat flow) is given by

$$\frac{\Delta Q}{\Delta t} = -kA \frac{\Delta T}{\Delta x}$$

where k is the thermal conductivity, A is the cross-sectional area of the heat flow, and $$\Delta T/\Delta x$$ is the temperature gradient.

Depending on what you can estimate, you may have an estimation of a person's surface area that's covered by the wet suit to plug into A. However, if not, you can always divide out the area so that your answer will be the rate of heat loss per unit area. The temperature gradient should be obvious, because you know the body temperature, you to know the temperature of the water, and you know the thickness of the wet suit that separates these two temperatures.

So I think the problem is solved.

Zz.

3. Dec 13, 2004

### Sophie_King

Thank you very much for your help.
The answers is always realy obvious when you know it!
Sorry i posted in the wrong area, i've only just joined the forum,
Thank you again