Describe how thermal conductivity of wall materials affects the rate of cooling of a building.

Wall material choices affect how quickly a building cools. In the Energy transfers in a system subtopic, a low-conductivity wall material reduces conduction from the warm inside to the colder outside, so the internal energy store decreases more slowly. This is a material-choice explanation, not a wall-thickness explanation. A strong answer compares high- and low-conductivity materials, links them to cooling rate, and explains why insulation reduces the energy needed for heating. Approved keywords to include in this revision point: thermal conductivity.