Answer, and give a reason. Why are the handles of pans made of wood or plastic?
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Answer, and give a reason.
- Why are the handles of pans made of wood or plastic?
- On a cold morning, why does a metal door handle feel colder than a wooden door?
- Why do birds fluff up their feathers in winter?
Need a reminder? The key ideaShow
Conduction: ; thermal resistance , adding for layers in series. : copper , aluminium , steel , glass .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) Wood and plastic conduct heat poorly, so the handle stays cool to hold.
Step 2. (b) Both are at the same temperature, but metal conducts heat from your hand much faster.
Step 3. (c) Fluffed feathers trap more still air, a very poor conductor, which keeps the heat in.
Answer: Low and high conductivities in each case.
Watch out. 'Feels cold' measures heat flow, not temperature.
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