Alpha Particle Detector

This experiment is for advanced students. Here is another way to detect cosmic rays, only this time you’ll actually see the thin, threadlike vapor trails appear and disappear. These cobwebby trails are left by the particles within minutes of creating the detector. (Be sure to complete the Cosmic Ray Detector first!)

In space, there are powerful explosions (supernovas) and rapidly-spinning neutron stars (pulsars), both of which spew out high energy particles that zoom near the speed of light. Tons of these particles zip through our atmosphere each day. There are three types of particles: alpha, beta, and gamma.

Did you know that your household smoke alarm emits alpha particles? There’s a small bit (around 1/5000th of a gram) of Americium-241, which emits an alpha particle onto a detector. As long as the detector sees the alpha particle, the smoke alarm stays quiet. However, since alpha particles are easy to block, when smoke gets in the way and blocks the alpha particles from reaching the detector, you hear the smoke alarm scream.

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10 Responses to “Alpha Particle Detector”
  1. Aurora says:

    Hmmm – it is working over here. Does this happen with any other of our videos? I would suggest logging out, and then logging back in to see if this clears it up. Let me know if you still need help.

  2. Tyler says:

    Hi misses Aurora, I tried clicking on the video but nothing was going on and I couldn’t seem to get it working, could you help me?

  3. Aurora says:

    I am not sure I understand your question – can you please ask again?

  4. Shiralee Seerden says:

    how dose it bern you


  5. Aurora says:

    Dry ice is the solid state of carbon dioxide (CO2), which needs very low temperatures to transform from gas to solid (a process called “sublimation”). This happens around 110 degrees below zero (Fahrenheit), and is very commonly manufactured by increasing the pressure of the gas in a confined space.

  6. Lorelei Grecian says:

    I know I can’t do this experiment because I’m not old enough but I have a question. Can you make dry ice? And also why and how does it get so cold?

  7. Lillian Jackson says:

    This is amazing! Thanks foe posting so many cool videos Aurora!

  8. Stephen Chisholm says:

    Thank you.

  9. Aurora says:

    Oops! Sorry about that. The video had rendering errors and wouldn’t even play on our system. We recreated the video and it’s being uploaded now, so you can try it out in a little bit. Thanks for letting us know! 🙂

  10. Stephen Chisholm says:

    I am trying to access the Alpha Particle Detector video, but it is not working. Can you please help? Thanks

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