If I knew what to say here it would be clever. #swimlyfe
Polymer absorbs water and expands. It keeps almost the same refractive properties as water and appears invisible.
The polymer is Sodium Polyacrylate (or similar)
Firstly. It freaks me out/worries me a bit about how many people reblog this and talk about using it to kill someone…
Please don’t use this to kill anyone. GENUINELY.
Before you try and plot the perfect murder, take heed. It takes a while for these things to expand. You’d be caught out pretty quickly when that person went to the ER/A+E for stomach cramps and they noticed an obstruction. Unsure if it would show up on x-ray, though…
As for your stomach - I’m unsure how a sodium polyacrylate ball of this size would react with the 0.1M HCl of your stomach or how fast/how it would break it down. I also don’t recommend you experiment, unless you’ve got some 0.1M hydrochloric acid lying around. If you DO have 0.1m HCl lying around, please test it and tell me! (I don’t have these balls in my lab).
Also, to answer some other reblogs on this post:
- If you made a suit out of this and stood in a pool of clear deionised water you would not become invisible. You would look very naked. However, if you wanted an underwater jelly-like invisible birthday suit, then this stuff is for you.
- If you made an underwater den out of this, you would be pretty easy to spot whilst sitting inside it as it would be completely transparent (and you would be completely opaque). However, it would still cover you, act as some kind of barrier and confuse your enemies. I’m pretty sure fish would probably try to eat it. In small amounts, sodium polyacrylate is used as a food additive.
- Remember that this probably wouldn’t work so well in the sea. Sea water contains many impurities that could potentially alter its refractive index. The refractive index of water is dependent on salinity and also temperature. Read more about that here and here. This means that depending on where you were to do it in the world, the effect would be different, and the hydrogel structure would be more or less invisible.
Learn more about refractive indexes here.