Quiz question.

[Bushwhacker]

Here's a nice little poser that I saw elsewhere, thought I'd post it here.

Walk along a beach at low tide when the sand is firm and wet. At each step the sand immediately around your foot dries out and turns white. Why?
The popular answer, that your weight “squeezes the water out,” is incorrect; sand doesn’t behave like a sponge. So what does cause this?

 

[Goatboy]

Is it because your weight displaces the sand under your foot, causing the surrounding sand to rise above the water level of the beach, so the water drains out?

 

[mountainm]

Are you sure its not due to compression squeezing the water out turning the sand effectively from a suspension to a solid?

 

[blacktimberwolf]

It's because the weight of the foot on the sand renders the sand aroud it less compact. The grains of sand seperate allowing any water present to infiltrate better, drawn by gravity, result....the sand dries quicker.

Anything else I can help you with .?

 

[Shewie]

It's because the weight of the foot on the sand renders the sand aroud it less compact. The grains of sand seperate allowing any water present to infiltrate better, drawn by gravity, result....the sand drys quicker.

Anything else I can help you with .?

What he said, but typed much better than I could've done

4:20 into this vid

 

[Bushwhacker]

It's because the weight of the foot on the sand renders the sand aroud it less compact. The grains of sand seperate allowing any water present to infiltrate better, drawn by gravity, result....the sand dries quicker.

Anything else I can help you with .?

A very concise answer indeed. Goatboy had right too.

 

[Firelite]

I'm with Goatboy - right first time.