Why are your hands slippery when dry, get “grippy” when they get a little bit wet, then slippery again if very wet?
In: Physics
Your body needs moisture to work properly. So the grip of your hands is kind of determined by all the ridges, and their ability to sell swell and squish. All those little lines, like your fingerprints and such, they fill with water when there’s moisture, and then when you grab things, they are able to apply extra pressure, creating better grip. Obviously this swelling is near microscopic, but have you ever stayed in the water until your hands prune? That is your skin swelling to give you grip in such a wet environment.
I’m using this to train for teaching my kids, hope this is good.
“Why can I masturbate dry, or with a ton of water in the shower, but not when my hands are damp?”
This reminds me; if you have slippery hands while riding bmx just rub a little dirt in your hands and your hands will be dry for awhile (close to an hour)
Im sorry if I dont understand this cause I dont have experience with American culture. But ELI5 like these confuse me.
They seem to be asking for explanations on things that aren’t true in the first place.
I mean no offense. But I wonder if the OP can describe what they mean by slippery when dry and gripper when slightly wet. In my experience, any amount of water makes things more slippery, except in circumstances where things like plastic bags stick to water.
Water sticks to water, making wet things stick to wet things. If the layer of water is thick the surfaces can easilly slide because water easilly slides across itself.
However, if the water layer is thin and the surfaces aren’t smooth then the surfaces can still touch in a lot of places. The water can still stick the surfaces together, but not be thick enough to make sliding easy, and the sticking caused by being wet makes sliding even harder than if the surfaces were dry.
A little bit of water (like licking your fingers to open a plastic produce bag) can help with grip in some circumstances but not all–this is why, for example, athletes sometimes use chalk bags.
If you’re talking about circumstances like opening a produce bag, then it’s more to do with surface tension than with any potential softening of the skin layer, I believe.
If your hands are slippery when dry, your hands are either dirty or you’re dehydrated. Hands are naturally quite grippy, of properly hydrated.
The surface tension of water is greater than the surface tension of your dry skin, which is mostly just tiny dead flaky bumps. Once you have too much water, no, you’re no longer dealing with service tension and now you’re dealing with fluid viscosity, which counteracts the tension.
Source: science and 25 years of hyperhidrosis presenting primarily in the hands and feet
Water has a high surface tension. Think of this as water molecules being so attracted to themselves that they minimize the surface area at any water/air interface. This is why water forms into beads or droplets. If you add a little bit of water to your finger and apply it to a plastic grocery bag or book page, when you pull away the top layer of the bag or book page will move with your finger. Separating from your wet finger would require that the water/air surface area increases against the surface tension force which is trying to minimise the area.
If there is enough water to produce a thin film between two sliding surfaces lubrication will occur. Some good examples of this are bearings, air hockey tables, or walking on wet brick. You would only notice this briefly while walking, but the thin layer of water would cause you to slip before your shoes contact the ground.
“There’s a fine line between between ideal friction and ideal lubrication.” – Dr. Ruth Westheimer
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