Thermal Radiation: The Most Important to Earth’s Climate

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 Today, Brian Jones and Sheila Ferguson, members of “The Little Shop of Physics,” taught us 13-year-olds about thermal radiation and thermal energy.

 Today, Brian Jones and Sheila Ferguson, members of “The Little Shop of Physics,” taught us 13-year-olds about thermal radiation and thermal energy.

First, Jones and Ferguson gave us Thermal Imaging Cameras. With these cameras, they invited us to look around with them. The coldest areas and materials were black, and the warmest were white. When we went outside, we took pictures of objects with the camera. Thermal imaging cameras are for learning about the world.

We took pictures of the sky, which was surprisingly dark. Very, very dark. There was a pole in the picture too, which was bright white. On sunny days, the sun gives off more energy. But on cloudy days, the clouds give off more energy because of cloudshine. NOTE: If you ever have a thermal imaging camera, NEVER point it at the sun.

We also took a picture of Jones. He was very white in the camera and his glasses were black. Mammals show up on the cameras, whereas cold-blooded creatures don’t. When Ferguson told us to look at the windows, we found that the windows were, in fact, dark. We couldn’t see through the windows, but we could see our reflections. Windows emit, but don’t transmit. The doors, however, were very white.

This is because of thermal energy. It is extremely important to Earth’s climate, which was a fact discovered by Tyndall in 1867. However, we can’t see thermal energy. This is because it’s wavelengths are much much longer than the wavelengths of visible light, making infrared light part of the invisible spectrum.

Because of the longer wavelength, infrared can interact with greenhouse gases and water vapor. If we took an thermal imaging camera into space with us, the Earth would shine as brightly as the sun. This is because the Earth is emitting the same amount of infrared rays as it is receiving from the sun, because that is where all energy comes from. What comes in must come out, in equal amounts.

After Jones and Ferguson answered very, very many of our questions, we did an experiment. There was a small black platform with three small square panes of glass, and a light-bulb warming the glass. We switched off the light-bulb and moved it, because it was still emitting thermal energy.

We took the temperature of the center of the first glass, then removed the glass. Then we took the temperature of the second glass center, then removed. We used the same procedure with the last glass center. Then, finally, the black platform center. It got warmer and warmer towards the black platform, the center of which was 50.7 degrees celsius.

Before we left, Jones and Ferguson gave us little packets full of liquid and one metal tablet. When we clicked the metal tablet, a white substance quickly filled out into the packet and hardened. It was very hot, it is a hand-warmer.

For more information, please visit their website at:
littleshop.physics.colostate.edu