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Author Topic: walking on air?  (Read 1514 times)

mugiwarafanatic

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walking on air?
« on: 24/07/2014 02:49:46 »
you know how when do a belly flop on the water it hurts because the water molecules couldnt move out of the way fast enough because of the amount of surface area ur body has and how fast you are falling? if, hypothetically speaking, a thing was created that had high surface area, could either slow down air or speed up you. would that work? of course, itd have to slow down air and thatd take extremely low temperatures, and it probably wouldnt be very practical for walking on air, but just for wondering's sake, would it hypothetically work?


 

Offline PmbPhy

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Re: walking on air?
« Reply #1 on: 24/07/2014 03:30:45 »
Quote from: mugiwarafanatic
hypothetically speaking, a thing was created that had high surface area, could either slow down air or speed up you. would that work? of course, itd have to slow down air and thatd take extremely low temperatures, and it probably wouldnt be very practical for walking on air, but just for wondering's sake, would it hypothetically work?
Welcome to the forum. Nice to have a new member! :)

What do you mean by could either slow down air or speed up you? It sounds like you're talking about a parachute. The purpose of the parachute is to give the person using the parachute an effectively larger surface area so as to slow him or her down.
 

Offline alancalverd

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Re: walking on air?
« Reply #2 on: 24/07/2014 06:51:40 »
The basic principle of aerodynamic flight, whether sycamore seed, insect, bird, aeroplane, hovercraft, helicopter or skydiver, is to create more air pressure below and less pressure above a moving object. 

In the case of unpowered flight, gravity wins, but more slowly the smaller the wing loading (weight per unit wing area). In the case of powered flight, you can maintain or gain altitude by adding thrust from the engine or flight muscles.
« Last Edit: 24/07/2014 06:53:11 by alancalverd »
 

Offline CliffordK

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Re: walking on air?
« Reply #3 on: 24/07/2014 22:14:12 »
If you hit the atmosphere at say, Mach 20, it could be like doing a belly flop on water.  At least with space orbital insertion, it is tricky to get the angle just right, at least in theory.  Too shallow, and one apparently "bounces of".  Too steep, and one burns up.  Just right and one aerobrakes in the thin atmosphere.

I believe Jupiter is supposed to have the atmosphere going through a range of densities to the point where it is denser than water. 

When thinking about "walking on water", there are a few issues.  Displacement, and surface tension. 

If the volume of your feet displaced the same amount of weight as the rest of your body, then you could stand, and walk on water.  Say you weight 50 kilos, then if you had clown shoes that displaced 50 liters of water, then you would be able to walk on water (assuming you had good enough balance).   

The surface of water also has a certain amount of surface tension.  Water skippers may be able to stand up on the water due to the surface tension interface at their feet.  Humans can simulate this by walking on surfaces such as jello (corn starch) which might not support the static weight of a person, but is enough that they can walk as long as they keep moving.  Perhaps you could also do it on water with large flat shoes.

As far as walking on air.  You could, of course, reach terminal velocity in a skydive.  But, to actually have air support you, you would either have to us wings like an airplane, or shoes made like blimps.

 

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Re: walking on air?
« Reply #3 on: 24/07/2014 22:14:12 »

 

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