Think of all the ways you can create heat! You can start a fire, run around the playground, rub your hands together, or turn on a heater. Let’s learn more about heat energy!
Heat is the transfer of energy from one object to another, due to differences in temperature. There are three main types of heat: Convection, Conduction, and Radiation.
Conduction is the transfer of heat that happens by direct contact.
Convection is the movement of heat by actual motion of matter. So, when a fluid is heated and then travels away from the source, it carries the heat with it. Metals conduct heat better than others. This is why we make our pots and pans out of stainless steel or copper!
Imagine a hot cup of tea. If you leave that cup of tea out on the counter, it will cool down because both the countertop and the surrounding air temperature is cooler. The heat is being transferred from the hot liquid and mug into both the countertop (conduction) and the surrounding air (convection). Now imagine a cold can of soda. As you leave this can of soda out, it will warm up, as the warmth from the surrounding air (convection) and countertop (conduction) transfers to the can and liquid. Want to test this energy transfer? Just move the can of soda or the mug and then feel the countertop where it was sitting. It will be a different temperature than the rest of the counter due to conduction!
Over time, both objects will reach thermal equilibrium, meaning they will match temperatures. As systems reach thermal equilibrium, the energy transfer stops.
All materials radiate energy based on their temperature: the hotter an object, the more it will radiate. The coil on an electric stovetop radiates heat. Seeing any metal glowing red is an example of radiation. Radiation, in combination with convection, heated-up our pot of water to make our mug of tea!
The study of heat and the transfer of energy is part of the study of physics, called thermodynamics.
Fun fact: Because fabrics do not transfer heat well, clothes work great to keep heat in, helping us stay warm!
