A stainless steel canister is filled with hot water and placed in a cold room. Describe the microscopic processes by which thermal energy is transferred from the hot water, through the steel wall, into the surrounding air.

State why the rate of thermal energy transfer from the canister to the air decreases as the water cools down.

A student wants to test the hypothesis that a canister with a shiny, silver outer surface loses thermal energy more slowly than a canister with a dull, black outer surface.

Describe, with the aid of a diagram description, an experiment to investigate this hypothesis. Your description should include:

• the apparatus used,
• the variables that must be controlled,
• the measurements to be taken,
• how the observations are used to reach a conclusion.