Exothermic and endothermic reactions

During endothermic reactions, energy is taken in from the surroundings. E.g. thermal decomposition. On the other hand, exothermic reactions, energy is released to the surroundings.

Endo thermic is heat taken in and exothermic is heat given off. — Think of a group of thermometers entering (endothermic) a sauna where they take in energy. Later on, the thermometers exit (exothermic) and go outside where they release energy to the surroundings.

Entering = Endothermic = taking in energy from surroundings

Exiting = Exothermic = giving energy out to the surroundings