Which term describes the hotness or coldness of a substance?

• A. Temperature
• B. Humidity
• C. Barometric pressure
• D. Wind

Answer: (A)

Temperature is the measure of how hot or cold a substance is. It reflects the average kinetic energy of the molecules in the substance and is what a thermometer reads when placed in contact with it. Temperature tells you whether something will gain or lose heat when it interacts with its surroundings, and it drives heat transfer between objects until equilibrium is reached. In environmental work, temperature helps predict energy needs (how hard a heater or cooler must work), affects water quality (warmer water holds less dissolved oxygen and changes reaction rates), and influences many atmospheric and ecological processes. Humidity, on the other hand, is about how much water vapor is present in the air; barometric pressure is the atmospheric force per unit area; and wind is the movement of air. None of those describe how hot or cold something is, which is what temperature captures.