Calcium Ammonium Phosphate

This compound is often used as a fertilizer, especially if the soil is acidic. It can also be used in a cold pack (where I got the crystals). When the solid is exposed to water, there is an endothermic (cooling) reaction. Here I dried out the salt and used crossed polarizing filters to view the crystals.

2 Comments Add yours

  1. tpollina says:

    Beautiful!! Could you create a post or indicate the protocol and the setup for this polarization?

    1. Puchina says:

      Thanks! You can check out

      Basically, I got a polarizing plate and cut it. Then I taped one of the plates to the LED light that came with my Foldscope. I brought the specimen into focus and then I put the other polarizing plate at an angle to the one on the light, but held it up to the part of the lens that was closest my eye. I then rotated the one that is not attached to get the most interesting image! Good luck!

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