Hot molecules move faster than cold molecules. When a fast molecule crashes into a cold molecule, the fast molecule gives away some of its energy and heats the other molecule. [3] X Research source For example, say you’re reading this article on your laptop (which is sitting on your lap). The bottom of your laptop is most likely warm and heating your legs, and that’s all because of conduction. [4] X Research source
For instance, let’s pretend you’re in a hot tub. As the water bubbles and moves, it begins to heat up and create steam. The bubbles and steam are a product of convection.
The sun is a perfect example of this. The sun’s rays can warm your skin as you sunbathe (even though you’re not physically touching it) because its electromagnetic waves travel from space to your spot on the beach. Every object above 0° Kelvin emits radiation, including you! This is why you may feel warmer standing next to someone on a cold day. [7] X Research source
With this in mind, radiation also follows the law of reflection and refraction, which explains how light and heat can bounce or change direction against a surface. [9] X Research source
If we were to go back to our example with the laptop, you’d most likely be able to tolerate the warmth from the laptop for a few minutes. But as the clock ticks, your legs will get hotter and hotter until you have to move the laptop away.
The crackling fire warms you and the bottom of the pot with radiation, emitting a hot light. As the water starts to heat up, it begins to bubble as the hotter molecules move up (eventually turning into steam) and the denser, cooler molecules sink. This is called a convection current. Heat is then transferred to the outside of the pot and the handle, thanks to the molecules rubbing together through conduction.
