Both conduction and convection are methods of energy transfer that need particles to transfer energy. However, convection happens in liquids and gases, in which the particles are far apart and are free to move randomly. Although the particles in liquids are closer together than gases, they are still able to move and flow.

Near the source of heat, the particles have a lot of thermal energy, so they vibrate and move much faster. This leads to the particles moving further apart, making the gas or liquid less dense.

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It is important to remember that the particles do not become less dense as they do not change in size, only the overall gas or liquid becomes less dense.

1. The moving particles with a lot of thermal energy rise and transfer energy to the particles at the top, replacing the particles with little thermal energy.

2. Particles at the top, which as a whole are cooler and denser, fall to take the place of the high-energy particles.

The constant cycling of particles is called a convection current. A constant current of particles, rising and falling with the transfer of energy to colder regions.

Let’s look at an example with water heating in a pot:

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1. The pot is heated from the bottom.

2. The particles at the bottom of the pan start to vibrate more as they are heated.

3. These particles then transfer heat energy to other areas of the pan and the water molecules at the bottom of the pan.

4. The water inside the pan is being heated using convection, which is why convection currents start to form.