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Comment by eande

2 days ago

Another one of these fascinating super absorbent materials is SAP (Superabsorbent polymer).

It is heavily used in diapers, tissues, water retention for plants, etc. SAP can absorb liquid up to 30-60 times its own volume.

https://en.wikipedia.org/wiki/Superabsorbent_polymer

I think it's more expensive, and I'm not sure it can absorb vapor (not liquid)

It's fun that it has the same refractive index as water, so if you put clear ones in water they disappear. Then you ask someone to put their had in a bowl with them for a surprise.

Aka orbees. Also useful as a soil amendment if you have clay soil, it stops it from claying so much and retains water underground for plants.

They make glow in the dark ones, which I put into a masonry jar with some distilled water and a drop of bleach, I light it from underneath with a USB LED and it glows for about an hour. Cool night time light.

Back in the early 90s they had a different name and they were irregularly shaped. This was for Soil Amendment. I think it started with a Z.