How do we measure the thermal energy of an object?

[Mr Davis 97]

I know that temperature is used to measure the average internal kinetic energy of an object, but how do we go about measuring thermal energy? It seems as though temperature could only compare the thermal energy of objects with the same mass and volume. But for objects with different mass and volume, this would not be the case. For example, a lake has a higher thermal energy than a roasting marshmallow, while the marshmallow as a higher temperature.

 

[mfb]

I know that temperature is used to measure the average internal kinetic energy of an object

It is not, but the concepts are related.
You can measure it by adding or removing a well-known amount of energy, and measuring temperature before and after.

For example, a lake has a higher thermal energy than a roasting marshmallow, while the marshmallow as a higher temperature.

There is the concept of specific heat and similar concepts, "[something] per mass of the object" - marshmallow and the lake have comparable specific heat capacities, and maybe similar specific thermal energy as well.

 

[crador]

It is not, but the concepts are related.
You can measure it by adding or removing a well-known amount of energy, and measuring temperature before and after.
There is the concept of specific heat and similar concepts, "[something] per mass of the object" - marshmallow and the lake have comparable specific heat capacities, and maybe similar specific thermal energy as well.

I'd say the roasting marshmallow has a much higher specific thermal energy, whereas the lake has a much higher total thermal energy. But maybe I am missing something.

 

[mfb]

Not sure about the specific thermal energy, water and ice have a large specific thermal heat capacity.

For the total energy, sure.