Educator Notes: 
This section shares more details about how conduction and convection can make a wildfire grow. Students may share some of the following observations about how wildfires are influenced by energy transfer:

Conduction
Objects must be touching to transfer heat through conduction. 

Example: A branch of a tree that is on fire touches another object in the forest, which raises the temperature until the second branch lights on fire, growing the wildfire. 

Convection
Hot air rises, while cold air falls with convection.

Example: Burning materials on the forest floor preheat the leaves and branches of shrubs and trees above the fire. The air rising can also lift burning materials like embers, which can grow the fire.

Radiation
Objects are not touching to transfer heat through radiation.

Example: Burning objects release energy in the form of heat. As the fire grows, heat radiates from the wildfire, and increases the temperature of the area close to the fire.

Observe the diagram below to think about how heat transfers in the world around us.

heat transfer methods. A diagram demonstrates convection, using circular arrows to describe how water heats up and rises, while cool water sinks. Wavy arrows show the principle of conduction, where objects close to a heat source increase in temperature.

Conduction

This is the process where heat moves between objects that are touching.

It happens because particles in a solid object vibrate faster when they’re heated. These faster-moving particles bump into their neighbors, making them vibrate faster too. This way, heat travels from the hotter part of an object to a cooler part.

Convection

Heat moves in liquids and gases through convection.

As a liquid or gas gets heated, it becomes less dense (or lighter) and rises. Once it’s away from the heat source and begins to cool, it becomes more dense (or heavier) and sinks. This creates a continuous loop or cycle called a “convection current”. It’s the reason warm air rises and cold air sinks in a room.

Radiation

When things are hot, they emit more of this energy.

Unlike conduction and convection, which need a material (like metal or water) to transfer heat, thermal radiation can travel through empty space. That’s how the Sun heats the Earth from so far away. The energy travels in waves and can be absorbed by objects, warming them up.

THINK-PAIR-SHARE

Based on the definitions above and what you’ve learned in class so far, how do you think that conduction, convection and radiation might contribute to wildfires starting and growing?