Question

thermal contraction refers to what? as heat decreases, mass decreases. as heat decreases, weight decreases. as heat decreases, volume decreases.

Explanation:

Thermal contraction is a physical phenomenon. Mass is an intrinsic property of matter and does not change with heat (unless there is a phase - change involving mass loss like evaporation, but that's not the general case here). Weight is related to mass and gravity ($W = mg$), so if mass doesn't change (in non - nuclear, non - chemical reaction cases), weight won't change with heat. Volume, on the other hand, is affected by temperature. When heat (temperature) decreases, in most substances (except for some like water in a certain temperature range around 4°C), the volume of a substance decreases due to the reduction in the kinetic energy of its particles, leading to closer packing.

Answer:

As heat decreases, volume decreases.