why is the base of a saucepan made of stainless steel but the handle is made of hardened plastic?

Question

what is the physics

Answer 1

Steel has high thermal conductivity, so the heat applied to its underside passes through very readily to cook the contents. But the heat would also conduct just as readily into a steel handle, cooking (burning) your hand, too.

The hardened plastic has comparatively low thermal conductivity, making it a good thermal insulator. It allows you to manipulate the steel pan while still being insulated from its heat.

Answer 2

The high thermal conductivity of the steel conducts heat efficiently from the stove burner to the saucepan's contents. The much lower thermal conductivity of the handle allows you to pick it up without being burned.