What is the name for a device that provides a thermally isolated environment in which substances exchange heat?

calorimeter

Explanation:

The calorimeter is a thermally isolated device from the environment and widely used in educational laboratories to study the amount of heat exchanged between two or more bodies of different temperatures. It is a very simple container, built so that there is no heat exchange between it and the environment. There are various shapes of calorimeter, but all are basically a thin-walled container that is surrounded by another thicker, more insulated closed container. The calorimeter prevents heat entering or exiting as in the thermos, for example.

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