手指中的細胞存在較高濃度的鹽，浸浴中，水會朝著更高的鹽濃度移動- (滲透原理), 令細胞中增加的水會導致它們膨脹，從而使手指皺起來（幻想一個充滿水被網包住的氣球）。而在漂浮過程中，由於溶液中鹽的濃度很高，手指中的鹽份和水中的鹽份更接近於相同的濃度，而瀉鹽作為調節劑並抑制水飽和在皮膚中，因此水不會進入手指的細胞而起皺。 但有趣的是，一個世紀以前，科學家已經知道這個好奇的反應不僅僅是一個簡單的反射或滲透的結果。研究發現，看起來很可怕的皺紋能使我們能夠讓我們在潮濕的環境中比較好抓住東西，這很重要啊！當祖先在溪流或是潮濕的環境中採集食物的時候，皺皺的手指，就像輪胎的刻痕一樣，是一條又一條的排水溝，把水排掉、增加了摩擦力，可以讓他們更容易擸食呢！
+ Will the skin go wrinkly when floating?
This is certainly one of the most asked questions, because it really WON'T!
Fingers wrinkle in bath water because there is a higher concentration of salt in the cells in your fingers, and the water follows the salt gradient (water will move towards a higher salt concentration)- osmosis. The increased water in the cells causes them to swell making the finger wrinkly (think of a balloon filled with water surrounded by a tight net). And in the pod, due to the hight concentration of salt in the solution, the salt in the fingers and the salt in the water are closer to the same concentration, and the Epsom salt acts as a regulator to inhibit water from saturating in the skin, therefore water does not enter the cells of the fingers - no wrinkling.
But interestingly, a century ago, scientists already knew that this curious reaction wasn’t only a simple reflex or the result of osmosis. Research has found that the seemingly hap hazard wrinkles allow us to get a good grip on wet objects. The wrinkles allow for water to drain away very effectively in similar way to the rain tyres you can get for cars which improve grip on roads. This would give us a clear advantage throughout our evolutionary history in certain environments. We would be able to climb up out of the water onto rock easier, hold wet weapons or tools better and even keep hold of wet prey.
+ Will our skin dry out after float?
No. Epsom salt is technically not natural sea salt, it is magnesium sulphate and not sodium chloride. It does not have the same drying effects on the skin, instead it exfoliate dead skins, draws oils from the layers beneath which creates baby-soft skin.