What is the difference between heat and temperature?

Heat and temperature are related but distinct concepts:

• Temperature is a measure of the average kinetic energy of the particles (atoms and molecules) in a substance. It's a measure of how hot or cold something is. Think of it as the intensity of the thermal energy. We measure temperature using scales like Celsius, Fahrenheit, and Kelvin. A higher temperature indicates particles are moving faster on average.

• Heat is the transfer of thermal energy from one object or system to another due to a temperature difference. Heat flows spontaneously from a hotter object to a colder object until thermal equilibrium (equal temperatures) is reached. Heat is a form of energy, and it's measured in Joules (J) or calories (cal). The amount of heat transferred depends on the temperature difference, the mass of the objects, and their specific heat capacity (how much energy is needed to raise the temperature of a substance by a certain amount).

Here's an analogy:

Imagine two containers of water. One is at 80°C (high temperature) and contains 1 liter of water. The other is at 20°C (low temperature) and contains 2 liters of water.

• Temperature: The first container has a higher temperature.
• Heat: If you mix the two containers, heat will flow from the hotter water to the colder water. The amount of heat transferred will depend on the temperature difference, the volumes of water, and the specific heat capacity of water. The final temperature of the mixture will be somewhere between 20°C and 80°C, but closer to 20°C because there's more cold water.

In short: Temperature is a property of a system, while heat is the transfer of energy between systems due to a temperature difference. You can have a high temperature with little heat (a small, hot object), and you can have a large amount of heat transferred with a small temperature difference (a large, hot object cooling slightly).