Why is it that you can survive a high fall into deep snow but not water?
In: Physics
Deep powdery snow can compress to an extent and absorb some of the energy of your fall. Water cannot compress, it has to move out of the way and the polar force holding water molecules together (surface tension) causes the surface of the water to behave like a solid for a split second when exposed to a high energy impact.
In large part it’s due to the compactibility of snow slowing your fall. There’s a lot of air trapped in there, and it will get packed more densely underneath you as it slows you down. Since water doesn’t compress, you need to displace it instead when you fall into it. If you’re moving faster than the water can get out of the way, it can feel like hitting a solid surface. It’s like the difference in pneumatic and hydraulic pressures.
Same reason falling onto sand would kill you, but a fall into a giant ball pit likely wouldn’t.
The snowflakes are only barely touching compared to water, which gives them lots of space to ‘give’ and compress.
Water, on the other hand, has no room to compress and has to be moved out of the way. Still better than solid ground (which wouldn’t move at all), but not ideal.
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