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CelticMadSci

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Posts posted by CelticMadSci

  1. It seems like you have two questions, chemicals interacting with the sun, and with magnetic fields. You're not going to get much influence from the sun's magnetic field here on earth.

     

    LCDs like you find in digital watches and calculators have liquid crystals in them that change polarization when subjected to an electric field.

     

    As for sunlight, invisible ink can become visible due to converting UV light in the sun to visible light, though that's not polarization, I know. This is how "brighter-than-white" bleaches work too.

     

    For something to become opaque in the presence of heat, citric acid ink will do this.

  2. Ok, here's a quick one that's very safe.

     

    I made an accopanying video: Rainbow Art - Thin Films.

     

    Materials:

    Black posterboard

    Nail Polish

    Pan of water

     

    1. Submerge the posterboard in water.

    2. Drop nail polish onto the water. Use an (sacrificial) eyedropper for bigger drops and bigger artwork. The drop will float like oil and then spread out, but dry because it is nail polish. It forms a thin film of thickness on the order of light wavelength to produce thin film interference.

    3. Lift the paper starting at one end to capture the delicate films.

    4. Let dry for several hours and you'll have beautiful rainbows.

  3. Hello,

     

    I'd like to share one of my latest experiments, a laser interferometer that I made at home with about $20 of parts (well, I used a green laser, but a red can work too). Of course, I had two mirrors, a lens to magnify the interference fringes, but how did I really save money? I used a 10 cent CD jewel case for a beam splitter!

     

    Even with this hacking, I got some crisp fringes, and I hope to use this to test the stability of my setup when I try making holograms again.

     

    Even though I'm only working with Class IIIa lasers, you should take care not to look into the beam or reflections. Laser goggles of a low optical density might be advisable.

     

    Here's the link to my explanatory video:

    Laser Interferometer - Homemade for $20

     

    For those who may not be familiar with an interferometer, it's just a device that interferes waves. The beam is split in 2 and the resulting beams are projected onto a surface via the mirrors to observe interference. In this case, by interfering light waves, we could potentially measure distances and movement on the order of the wavelength of light, say 532 nm. Michelson & Morley used a device like this to measure the length of a meter accurately and also show the lack of a luminferous ether (a medium for light) thus showing that the speed of light is constant.

     

    Hope you enjoy it. :)

  4. Hi all,

     

    Celtic Mad Scientist here. I'm studying for my Ph.D. in computer engineering but I'm a science enthusiast too (physics, some chemisty, some astronomy). Optics and lasers are particular favorites of mine.

     

    I'll especially be hoping to share some of my experiments with you over in the Amateur Science section.

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