Why do we want to group materials? what advantages does it have?

Question

2. A saucepan is largely made of metal with only the handle and sometimes the lid being made of non metal materials. Explain why these materials have been chosen in each case.

Answer 1

Metal passes heat. So, if you put the saucepan on a fire, the heat will be transfered along the handle and the handle will be hard to hold cause it's hot. In order to prevent this, the use of non-metal materials will be helpful cause non-metal don't transfer any heat.

Answer 2

Metals contain free electrons.  Free electrons allow energy (in this case heat) to transfer quickly through the whole of the material.  If you used metal for the handles and lids then they would get hot with the saucepan.  Non metal materials dont have free electrons and will therefore not conduct heat as easily making them insulators.  They will remain cool when the saucepan get hot so that you wont burn your hand when you go to pick it up.