How does Matter Transfer Thermal Energy?

M.R. Anglin
M.R. Anglin
A metal pan on a hot burner conducts thermal energy.
A metal pan on a hot burner conducts thermal energy.

Matter will transfer thermal energy in one of three ways: through conduction, convection, and radiation. When two objects of differing temperatures are put together, the objects will endeavor to reach thermal equilibrium. That is, heat will be transferred from the higher concentration to the lower concentration—from hot to cold. In other words, the hotter object will transfer heat to the cooler object until both objects have the same temperature. Once the objects reach equilibrium, they will tend to stay there unless there is some sort of external change.

The movement of water molecules in boiling water is an example of natural convection.
The movement of water molecules in boiling water is an example of natural convection.

The molecules in an object with higher thermal energy vibrate faster than an object with low thermal energy. The moving molecules can then bump into other molecules, causing them to move as energy is transferred. Conduction is what happens when objects transfer thermal energy by molecules bumping against each other. This can be seen when a metal spoon is dipped in hot tea. The molecules from the tea vibrate against the molecules in the spoon, causing the molecules to speed up and thus causing the spoon to heat up.

Another way to move thermal energy is convection. Convection has to do with heat being transferred through the movement of fluids. There are two types of convection: natural and forced convection. Forced convection uses objects like a pump or a fan to move fluids and transfer heat. Examples of forced convection include convection ovens and fluid heat radiator systems.

Natural convection occurs when a fluid has two different temperatures causing differing densities. An example of natural convection is water being heated on a stove. The heat from the stove heats up the bottom of the water, causing the molecules to vibrate faster. When molecules vibrate, they expand and lose density, causing the warmer water to rise and the cooler water to sink. The cooler water will then heat up and rise to the top. The circular current this process produces is called a convection current and is responsible for many aspects of the weather.

The last method the world uses to transfer thermal energy is radiation. With radiation, objects can transfer thermal energy through a vacuum. This is the type heat transfer by which the sun warms the earth. In this process, thermal energy is transferred in the form of infrared rays. Though thermal energy can be transferred through radiation, we feel the heat when the infrared rays strike an object, like air, and cause the molecules to move faster, thus heating up.

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Discussion Comments


@miriam98 - I think that they do see it, but I am not sure that wind power is not without its pitfalls.

I am well aware that some well known oil industry tycoons have pushed the idea of windmills filling the land and providing us with most of our energy needs, but there have been some glitches in even implementing windmills on a small scale.

There have been reports of wildlife, for example, being caught in the wind mill rotor blades, messing up the windmill and of course killing the wildlife. On a less destructive note, there is also the problem of the aesthetic appeal of windmills. Many residences don’t want windmills perched nearby, potentially adversely affecting their property values.

I am not saying that I subscribe to all the notions myself, but we do need to have a discussion about the pros and cons of wind energy in my opinion.


@NathanG - Tornadoes are definitely bad news. The good news is that we can tap winds to create energy in a way that is useful and helpful, not destructive.

I think that wind power is one of the best renewable source of energy. Windmills can easily generate heat and electricity, and store that energy in batteries when the winds aren’t blowing strong.

I personally believe that we could combine wind and solar power to create a bulletproof solution. The solar cells can capture the energy released by the sun’s radiation, and the windmills can trap the winds as they pass by.

I don’t know why so many of our politicians don’t see the usefulness of renewable energy and jump on the bandwagon more aggressively.


I live in tornado alley, and so I know of one destructive way that nature taps Earth for energy each year.

A tornado basically results from convection currents. We live in the middle of the country and so we get both cold fronts and warm fronts meeting in our area.

When strong warm fronts meet with the cold fronts, they create a current in the air, with the heat transferring to the cold as the article talks about. In the worst case scenario, you wind up with a tornado.

What’s surprising to some people is that tornadoes can follow on the heels of relatively warm, uneventful weather patterns; some people mistakenly think that you need a very strong storm system.

In reality, all you need is hot air and cold air getting together, and then the tornado forms.

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    • A metal pan on a hot burner conducts thermal energy.
      By: Spectral-Design
      A metal pan on a hot burner conducts thermal energy.
    • The movement of water molecules in boiling water is an example of natural convection.
      By: Ioana Davies (Drutu)
      The movement of water molecules in boiling water is an example of natural convection.