Eli5: Entering water on terminal water


So I have had this general curiosity for a while. Could one, in theory, be falling at terminal velocity and approaching towards water use something to break the surface tension of water and survive?

In: Physics

Surface tension is just part of the problem. The other is that water is really heavy, and it has to get out of the way quickly in order to let you sink in. Moving heavy stuff quickly requires a lot of force, which is transferred into the body, leading to injuries.

What can help is to pump air into the water. This 1) breaks surface tension, 2) replaces some of the heavy water with light air, lowering the average density and thus force required to push it out of the way.

In general, to brake falls, you want something that poses little resistance at the beginning (so you slow down gently) and more at the end, so you actually stop moving. Thus, air cushions or nets are popular choices.

You cannot “break surface tension”. It is an inherent property of water like density. You would not say you could break density.

You can however change it. As one poster said, you can change the bulk density by having air bubbles in the water and you can add soap to significantly reduce surface tension.