Joe noted that the temperature in his aquarium dropped overnight. He concluded that thermal energy moved from the aquarium to the air around it. Does this validate or invalidate the Law of Conservation of energy?

validate

Explanation:

Law of Conservation of energy

According to the law of conservation of energy, energy of a body or a system gets transferred to another system as different energy. We cannot create energy nor we can destroy energy. Energy is always transformed into other forms of energy.

In the context, Joe noticed that the aquarium's temperature dropped during the night and he concluded that according to the law of conservation of energy, the energy of the aquarium in terms of thermal energy is being transferred to the surrounding air.

This is because the aquarium is considered to be an open system where energy can come in and move out.

Hence Joe's statement is valid.

It validates the law of conservation of energy