Newspaper Radiation! [W/Video]

Newspaper Radiation! [W/Video]


Radiation is the transfer of thermal energy using electromangetic waves, which includes visible light, infrared radiation, ultraviolet radiation, x-rays and microwaves and radio waves. A camera flash is designed to give off a whole lot of visible light in a short amount of time. The black ink in the newspaper absorbs this radiation and increases in temperature, while the blank paper reflects the light and does not warm up nearly as much.

Let us know in the comments below if you think this demo is something you would use in your classroom.

This video was produced by The Little Shop of Physics at Colorado State University in partnership with GE.

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Comments (12)

  • Chris Ertl Reply

    This looks great! How much and when will it be available?

    March 3, 2016 at 4:08 pm
  • Peter Edmondson Reply

    The demo is a great idea. One potential problem is another variable beside color – plain paper vs ink. If the white spot had a white ink similar to the black spot having black ink then it would control that variable better. Color is one variable, but the composition of the spot of color is another not accounted for in this demo. Great demo I can use to stat that discussion and then duplicate with our own controls.


    March 3, 2016 at 4:12 pm
  • Paul Burgmayer Reply

    I have a problem with this demo. The white and black portions of the newspaper are not equivalent chemically. In the case of the black paper, there is carbon black and the chemicals added to get it to stick to the paper. I imagine the smoke is the binder vaporizing. In the case of the white paper, neither of these are present so you don’t get the smoke.

    As an alternative, I wonder about putting a sheet of heat sensitive liquid crystal under them both and seeing what color you generate when black and white portions are flashed.

    March 3, 2016 at 4:28 pm
  • Ken Larson Reply

    Nice demo. Could you recommend a particular flash unit that you know would work for us to do this demo?
    Ken Larson
    Luther College Physics Dept.
    Decorah, IA 52101

    March 3, 2016 at 4:42 pm
  • MIchael Garlick Reply

    Awesome Demo Brian, can you tell me the spec’s on the flash unit you were using, it looks like a very high output commercial flash, how much would one like yours cost? If I wanted to add your demo to my bag of tricks? have you used an optical pyrometer to measure the temperature at the instant of flashing, that might be very cool piece of data to add, Temp of black verse temp of white square at the flash point.

    March 3, 2016 at 4:46 pm
  • J Greenhough Reply

    Cool. Yes it would be useful.

    March 3, 2016 at 4:59 pm
  • Maria Knueven Reply

    This is a simple quick demo that is also cheap if you have a flash! Perfect for students to turn an abstract concept into a concrete visual.

    March 3, 2016 at 5:08 pm
  • Maria Knueven Reply

    This is a simple quick demo that is also cheap if you have a flash! Perfect for students to turn an abstract concept into a concrete visual.

    March 3, 2016 at 5:09 pm
  • Marc Kroger Reply

    IR cameras for cell phones are pretty cheap. It would be cool to video the IR view of the paper before & after….. Does our journalism department have a flash unit big enough for this? I’ll soon be finding out….

    March 3, 2016 at 6:13 pm
  • LaNissa Spear-Jones Reply

    This is a simple but interesting way to implement critical thinking skills in comparing variables.

    March 3, 2016 at 6:25 pm
  • Ellen Gordon-Ross Reply

    Great way to get students talking physics.

    March 4, 2016 at 10:25 pm
  • Paula Hitt Reply

    An infrared thermometer could read the temp of the paper right after applying the flash. They are $10 and up. What would really be cool is if you had an thermal imaging camera ($300+). Hold the flash a little higher above a black/white picture, flash, then let infrared camera record what areas are hotter and project them visually – if real time, students could see the heat dissipating, too.

    March 28, 2016 at 8:16 pm

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