Walk/Run on water

[Yvtq8k3n]

Lets forget the intro and lets get to the point.

 

What is required in order to walk/run in the surfice of the water? Speed? density? I remenber there is a specie of lizard that have the ability to walk on the water, so my question is how? and could we also do be able to do it?

[fiveworlds]

You can walk on custard....

[DrP]

yea, custard is non newtonian, so can run on it... but you'd probably sink if you walk.

[Phi for All]

I think you'll find that any of the ways to maintain an equilibrium between momentum, weight distribution, balance, and the rapidity of your stride are going to be short-lived. How long can you run at your fastest speed while taking short, choppy strides so your feet don't go too far under the water?

 

Iirc, the lizard's hind legs are splayed out wide, and they get that whole body including the tail in on the movement so they are really moving fast. That won't work for us. I've seen guys attempt this running on from the shores of a lake (not the hoax guys), and while you need speed we'll never have, you also need to take your next step before your last one can sink. This requires short steps at high speed, something that is difficult/impossible to maintain.

[Yvtq8k3n]

You can walk on custard....

 

 

yea, custard is non newtonian, so can run on it... but you'd probably sink if you walk.

 

That is not bad but the question, was why the lizard can run on water and why we cant,

I think you'll find that any of the ways to maintain an equilibrium between momentum, weight distribution, balance, and the rapidity of your stride are going to be short-lived. How long can you run at your fastest speed while taking short, choppy strides so your feet don't go too far under the water?

 

Iirc, the lizard's hind legs are splayed out wide, and they get that whole body including the tail in on the movement so they are really moving fast. That won't work for us. I've seen guys attempt this running on from the shores of a lake (not the hoax guys), and while you need speed we'll never have, you also need to take your next step before your last one can sink. This requires short steps at high speed, something that is difficult/impossible to maintain.

 

So is required all part of the body in order to create balence or maybe if the feet dont sink i will be able to stay on the water.

Lets image that now i have an tail like the monkeys, would that allow me to mainten more balence and help me to not sink?

Edited June 16, 2016 by Yvtq8k3n

[Strange]

Lets forget the intro and lets get to the point.

 

What is required in order to walk/run in the surfice of the water? Speed? density? I remenber there is a specie of lizard that have the ability to walk on the water, so my question is how? and could we also do be able to do it?

 

 

In the case of the lizard, it is almost closer to swimming than walking: http://news.nationalgeographic.com/news/2004/11/1116_041116_jesus_lizard.html

 

Other animals rely on surface tension:

http://voices.nationalgeographic.com/2014/06/19/walk-water-animals-science-weird-environment-world/

[Phi for All]

So is required all part of the body in order to create balence or maybe if the feet dont sink i will be able to stay on the water.

Lets image that now i have an tail like the monkeys, would that allow me to mainten more balence and help me to not sink?

 

I'm not sure if the fastest human runner can overcome gravity's effect on our mass. The tail helps the lizard because of the way his legs work, but he isn't pulled down into the water as quickly, so his swimmy/runny locomotion takes advantage of the surface tension in a way we never can.

[MigL]

What the heck is the matter with you guys.

Custard is for eating, not walking on !

[Velocity_Boy]

Lets forget the intro and lets get to the point.

 

What is required in order to walk/run in the surfice of the water? Speed? density? I remenber there is a specie of lizard that have the ability to walk on the water, so my question is how? and could we also do be able to do it?

 

 

To avoid sinking, you need to generate thrust equal to your weight. You generate this by pushing water down and backwards with each step. For a size 9 shoe, you can’t push more than around 3.5 litres of water at a time or you would sink too far and friction with the water would slow you down too much.

So that 3.5 kg of water has to be pushed back fast enough to offset your weight. If you weigh 75 kg, my back-of-an-envelope calculation suggests you’ll need to push it back at around 11 m/s.

Since the water moves back as you push it, you need to go twice as fast as that or you would stand still. So that’s a running speed of almost 80 km/hr, which would be quite impossible even in my idealised calculation that ignores things like fluid drag.

[Yvtq8k3n]

 

 

To avoid sinking, you need to generate thrust equal to your weight. You generate this by pushing water down and backwards with each step. For a size 9 shoe, you can’t push more than around 3.5 litres of water at a time or you would sink too far and friction with the water would slow you down too much.

So that 3.5 kg of water has to be pushed back fast enough to offset your weight. If you weigh 75 kg, my back-of-an-envelope calculation suggests you’ll need to push it back at around 11 m/s.

Since the water moves back as you push it, you need to go twice as fast as that or you would stand still. So that’s a running speed of almost 80 km/hr, which would be quite impossible even in my idealised calculation that ignores things like fluid drag.

 

Thanks man, that was the answer i was looking for, could u tell me the math's u did(dont need to me acurate), just to have an ideia.

Edited June 18, 2016 by Yvtq8k3n