The Wet-Sand Effect

[TheZse45678]

are you an ice skater

[habbobaby1]

Ein Fußabdruck in feuchtem Sand ist trocken, weil der Druck des Fußes die Sandkörner verschiebt und dadurch das Volumen vergrößert wird. In den nun vergrößerten Porenraum dringt das Wasser ein, wodurch die Oberfläche trocken erscheint.

[epSosDE]

Sand increases surface and empty spaces under pressure.

[EngyElms]

Its just consolidation!!!

Congratz, your weight forced the water outta the sand!

Now go squeeze a wet sponge :D

[DravenX53]

@EngyElms Not quite. Watch the video again; squeezing the bottle forced water INTO the sand, not out of it. That's the counter-intuitive part here, it's like the opposite of squeezing a sponge.

[95lillen95]

dude, this is freaking hardcore sciens... o.O

[sharpshard]

I'm surprised that cohesion between particles didn't come up. The water makes the sand more cohesive (a.k.a sticky) than just normal dry sand. The larger of the cohesion, the bigger the shear stress between adjacent particles. This is where dilatancy comes from for wet sand (and also why wet sand can be characterised as a dilatant fluid). There's a critical sand-to-water fraction for maximum cohesion.

[TheReasonWhyGuy]

Stupidly simple... compacting sand decreases gaps where water resides, thus pushing water outwards... not completely drying, simply decreasing the amount of wetness.

[VarykGerai]

@TheReasonWhyGuy no! look at the bottle, when he squeezes it water isnt pushed out, water is sucked in. Read the freakin description.

[Tartrus1]

@TheReasonWhyGuy Except that isn't what happens... as you see in the water bottle test. The effect of squeezing the sand allows more water to flow into the bottle.

[seejimmyrun]

dry fail :26

[shakenama]

The explanation seems really complicated. I prefer this explanation.

Much like salt, sand has air spaces between each particle. At the beach these spaces easily fill with sea water. When you press or step on the sand, you make the sand more compact and dense, removing the spaces. Then there is no longer any space for the water to permeate and the water is displaced causing the sand to be temporarily dry. :-D

[trymesucker]

So that is how that thingy works with the air pressure thingy thing of thingyness... u kno, with the bottle of da sand?

[Axgoodofdunemaul]

I've always been told that a bucket of dry sand is heavier than a bucket of wet sand. I sure am glad somebody is willing to do this science. It's the only thing that keeps the zombie plague from starting. We're all grateful.

[Axgoodofdunemaul]

I've always been told that a bucket of dry sand is heavier than a bucket of wet sand. I sure am glad somebody is willing to do this stuff. It's the only thing that keeps the zombie plague from starting.

[solider033]

woaaahhhh very ugly fooooot :X

[stex013]

nice legs ahahahaahha

[SillySkittle2142]

Whoa so it creates a potantially dry area around the area of where pressure is added........I FEEL SO SMRAT!

[brad10474]

It's a non-newtonian fluid like cornstarch and water

[MortallicA91]

i would say squeezing the sand makes not enough place for the water, so because water moves more "comfortable" it is the one it will move away for the sand to take its place...

if gravity on earth was at a bigger amount it would happen the same without the need of squeezing it...

i just made it up from mind... am i that wrong?

[Deceptibotautocon]

What's with that media and dilantacy apparent...blah blah blah. All i know is that this is awsome.

[wcburns]

This is important how? ditto on the ugly feet.

[dogsluvme123]

dude you have ugly feet

[RplixAirsoft]

i would have guessed light refraction :P

[MegaTim42]

This is incorrect. The sand around the foot is not completely wet anymore because it rasied in hieght above the other areas of sand.

[TheTr4pt]

You need to stop making videos and end your life. Right now.

[Dragonspirit999]

a quicker way of doing this is a towel DUH!

[rage13371]

u make the boringest videos in the entire youtube community

[digger30078]

cool vid

[blackbandan]

I noticed that before too when I walk on the beach

[Seanlong38]

The reason that wet-sand partially dries when force is applied is because you force the liquid out of the sand, causing the liquid to move out and down, because your pushing the water out of the sand where pressure is applied. The only thing I don't understand is how the water level in the tube fell during the bottled test, rather than rising as it should have, please explain!

[jaimy22]

and then and then and thenandthenandthenandthen....

[halo18hockey]

fuck you

[ProDigit80]

It's because the sand you stand on goes down, and the surrounding sand has no other way than to go up!

Sand that goes up gets dry because it's higher than the water level. You should do a horizontal cam shot over the surface to see what I'm saying is true!

It's just because of the difference of level between water and the risen sand (due to being squeezed it finds a way out to rise around the foot or object that presses it down).

Nothing out of the ordinary.

[criscros7]

"It's because the sand you stand on goes down, and the surrounding sand has no other way than to go up!"

And how is that supposed to explain the rising of the water in the tube attached to the bottle in the end of the video?

[nefets99]

yaeh your right, but it still looks kinda cool

[Inquisiturient]

Well, explain the water bottle example. Since the sand doesn't leave the container, it would be odd that the water above would go down instead of up.

[helstontvx]

and?

[pod0boq]

Man, whoever discovered this phenomenon was feeling original when they named it.

[MrTroat]

Did You have six toes on your left foot? Gross..

[twilightvengance]

(count again....)

[TheAppleHat]

did u learn to count from a zebra?

[brokehart]

i cant believe u find ths so fascinating that youd make a vid about it........then again, i walk on the beach everyday but some people havnt evn seen th ocean before

[sonnifer]

yeah, because all of the water in the sand surrounding the foot connects with the water that has been pushed together under the foot.

[Kevintb10]

you have nastey feet

[AdminOnDuty]

And all this time I thought this effect was caused by the pressure shearing through the cohesive skin of the water making it 'wetter' and allowing it to occupy the tighter spaces that result from compressing the sand particles together. Are you sure the volume of the sand increases under pressure?

[ooglebag]

.....sigh.....

[TheLivirus]

Don't you find weird that the bottle is sucking in more water while he squeezes it? Watch the whole video stupid.

[TheLivirus]

Then you were taught wrong. Because he's not pushing the water out from the sand. The sand sucks in more water when he squeezes the bottle. Read my comment again, and see the video again, please.

[bensonak47]

i hate your feet stop filming your feet

[PaulNaoki]

ugly left foot

[MonteLSV6]

lmao

[sjeessjees]

agree. damn....

[digger30078]

@PaulNaoki stop being mean at least it was cool your foot probaly be uglyer then ever so stop talking!!!!!!!!!! :)

[PaulNaoki]

@digger30078 wanna see my foots on the beach? pal :p

[solider033]

@PaulNaoki only left foot???? woaaah terrible legs :S

[mrflyer107]

@PaulNaoki poor him

[laputahayom]

i wonder if there are any implication to this.

[Blaze0820]

lol hes cool an interested in these things....

[onimus93]

actially its not obviouse, and its actually pretty interesting, i always though of youre foot as soaking up the water

[nogravity60]

lol

[speedstakerguy]

Go fuck youself Bob.

(reply to thiemoo60)

[HapeeHeathen]

wtf was that? that was obvious as hell

[franzakinobliks]

weak

[radarsaysradar]

uhh.. duh?

[54spiritedwill54]

that is so awsome

[CalieProductions]

COOL BEANS

[epicenur]

the last one is basically is how we humans pee

[Aoife211]

your videos are great! all that physics looks ordinary. however when you make a vid with all the reasons why is it so it makes it very interesting.

[bobbydo7777]

dude who cares!!!! man this was stupid

[ssbbb]

ugly feet

[kurt2161984]

wow what a video upload i really enjoyed that..... ggggggaaaaaaayyyyyyy

[fudruckers90210]

gross feet

[aruseb]

lol shows how much attention you are paying.

[fudruckers90210]

for the first 30 seconds of this video there are two things: sand and feet. you'd have to have ADHD not to look at them.

[Daghead]

wtf!

[Corbenik]

the learning it burns!!!!

[fifteentwelve]

I don't know much about the physics of this, but I wanna try to explain in the simplest terms.

Usually, the particles of sand are relatively compact and hold water. When a force is applied, the particles space out and the gap between them increases (though it's still a miniscule amount in the large-scale world).

This allows the water to flow into the spaces under the influence of gravity. The sand dries up, but when the force is withdrawn, it becomes wet again.

Is that right?

[alecTHElion]

sorta, its called a Non-utonium liquid, and its actually the opposite, compression forces the water out, as its less dense

[killall217]

alec, you are thinking of non-newtonian fluid. being a solid changing into the state of a liquid in a matter of seconds without being tampered with, however if you touch it while it is drooping out of you're hands it feels as a solid. ingredients to non-newtonian liquid: simply water and corn starch! :)

[NHLfreak87]

gimme 80 seconds back! now!

[speedstakerguy]

no go fuck yourself.

(reply to NHLfreak87 )

[NHLfreak87]

ok it took me about 15 seconds to read that and write this so....gimme 15 seconds back! now!

[boobookittyfuck84]

I ABSOLUTELY love how up in arms everyone gets. Rather than stating your opinion about the video in a well understood intelligent way everyone feels the need to berate one another with semi-well worded cheap shots. Reading these comment boards (especially this one) makes me feel like i'm back in 11th physics class... This isn't a pissing contest guys, it's shitty video about some guy trying to explain a naturally occuring event without an the means of chemistry or physics. COME THE FUCK ON!

[420Hallucin8]

i just witnessed "the boring video effect"

[Bumsesh]

I want my 1:20 back.

[xxPUMISTAxx]

it should be the dry sand effect

[nicefade]

Now I can finally get some sleep...oh wait I was, now I have to go back and see how this video ends.

[babiiashley34]

u have some crusty ass feet

[hybrid41]

fake...it's photoshopped

[lilfitz99]

dumbass its real

[hybrid41]

duh ya think...just wanted to see if some retard would respond.U WIN!!!

[stinkybproductions]

i remember this from the beach............

i always wondered about that

[Qbuilderz]

ew, nasty feet - neat vid though

[maonman]

that is so awsome

[freedomtagard]

no hes a superhero

[KhmaiBodian559]

BILL BILL BILL BILL BIL!!

[marshalnd]

bill bill bill bill nye the science guy...o.0

[KhmaiBodian559]

yea hahaha

[rocknrolla111]

haha nice

[marshalnd]

XD hey there mr science guy!!!lol

[Devdraco]

This is a very interesting video... People just can't appreciate it, because they know it, and should stop COMMENTING if they're not here to learn about what psidot does/knows. I have spoken.

[haytoo]

wow your smart. I've always wondered about that.

[boobookittyfuck84]

I am fairly certain of two things. One, there is no such things as The Wet-Sand Effect. And two, this guy has way too much time on his hands.

[marqphil]

fuck you

[holyfrickencrapyeah]

ok its not that cool, when you step on the sand the pressure makes the sand around ur foot rise, and the water drains out of the elevated sand making it a lighter color, its still wet...and not cool at all. dumb video.

[Treemeadow]

Beach Physics! Thankyou so much! You have just inspired a whole unit of future science lessons with my students!

[Serph113]

...Can I be in your class? Field trips to the beach! Woo!

[marqphil]

settle down dog

[byzantines2000]

yeah, you have some messed up ogre toes =P

[holidayizon]

i hate feet. gross.

[Devdraco]

Well, shouldn't you hate your own, then?

[lordcat33]

i aggree with matty.

[mattygersh]

marshalnd, please be quite and let people that have brains do the talking. seeing as how your brain is so limited perhaps you need a bit of a more extensive explanation

compacting something would be lowering the volume the substance is occupying. the producer of the movie explicitly states the sand momentarily INCREASES its volume under pressure, opposite of compaction. perhaps the 'extremely difficult way' was necessary but retarded people do have trouble thinking in the first place don't they

[marshalnd]

ehh...sorry...i major in common sence...asshole

[marshalnd]

and another thing...i bet he is one of the few nerds who has a terabyte computer

[marshalnd]

id say its because the feet are compacting the sand thus pushing the water out but sure you can put it the extremely difficult way too

[HokageG]

pushing water out? when he squeezes the bottle it soaks up more water..

[2007wschamps]

yeah those feet should never be seen in public again!

[pottsi4]

y do u call it the "wet-sand" effect?

[psidot]

In their book "Rheology: An historical perspective" (Elsevier, 1998) [Rheology is the study of the deformation and flow of matter] R. I. Tanner and K. Walters on page 73 refer to it as the wet-sand effect. The effect is an example of Reynold's dilatancy and usually goes by this name.

[aztecoutback]

you FEET are weird looking.

[kaos12fly]

Umm, isn't this kinda basic? I mean, you are just displacing some of the water, its not thing special. Like the bottle, you are just squeezing water out. How does the fact that there is sand in it make it any more exciting or special?

[freshjives3]

What is this bullcockery everbody knows this bullshat

[qwertyg33ks]

go try it.

[freshjives3]

i already tried it tats why im saying wat is this bullcockery everyone knows this bullshit

[qwertyg33ks]

I meant with saturated sand... cant you see that water goes away from your feet when walking. when you tap your feet over the same place, water comes back.

[nothinrhymeswithalex]

Interesting but whys teh water blue in the dish and bottle

[psidot]

Just so that the water is easier to see. The blue colouring is nothing more than food colouring.

[Xanderthedestroyer]

I think your videos and information are cool, alot cooler than coming onto youtube and talking smack "cough" (thats you mr. d-bag hater boy whos about to leave some stupid negative comment)

[timtima724]

can i see your feet again

[JeMaAlNa]

I guess it could also be called the "Partial-Drying Effect"?

[uzack3]

boring!!! omg sand!

[KFDonny]

so this will give us the cure for aids.

[b33133rice]

I'm a subscriber now. I want to see more of these.

[Jawblues]

useless test! if you test something do something usefell with your lab equipment

[dm4men]

useless comment! if your going to comment on something make it a good one, do something useful with your time

[1255674556666]

Interesting, thanks.

[purplepisces15]

awesome

[DevilsandMets4life]

thats very interesting..i always saw it happen...but didnt know y...thanks

[DumbDaily]

all you need is a parachute and you could catch crazy salmon with those talons...SWOOP

[singlespies]

interesting - I always thought it was that the sand was just squeezing the water out of the way but I just read about "Reynolds' dilatancy" on wikipedia - cool!

[jw81176]

ugly feet

[rawwqq]

I've always noticed that but never saw why. Thanks for clarifying.

[Alexvideoclip]

A little step for a man, a giant leap for mankind.

[UnitedAbominations69]

nice feet. lol

[ayshamarty]

huh, i've always wondered why that happens :)

[MyHaloVids]

yet another simple experiment. the sand doesn't soak up the water, seing that it's made of up tiny particles of rock. so once you press the sand, it compresses and the water is forced out of the way. seriously this is simple but interesting.

[skushroom]

no one revises anymore... most skip school, i just don't revise ^.^ ppointless vid dude. try making people laugh, tis one of the main ideas of youtube these days xD

[joezhangjiyao]

wow physics!

[fk2891]

your comments are really stupid

[davidsmallplanet]

Water is at its densest at around 4.5 c would the effect work if the water was at that temperature?

It must be the water getting denser otherwise how could the water immediately return back to fill the space between the grains of sand?

[dcv1977]

Seriously, go and find a job to pass daytime

[FabiNeme]

Wtf is that ?

[PspH3lp3R]

ugly feet

[jovicakluk]

and you probably got an ugly face

[Eyewash03]

wow! you must really love sand.

nasty ass feet by the way. This video looks like a first person view of a retard stalking someone on the beach

[ORCA4312]

Interesting science videos. Nice job.

[charliedip]

What's the point? Is there a second video to this?

[dudeguy2]

you got some freaky ass looking toes dude

[Vamooska]

Sand in my crack is called the irritable Vammy effect. It causes rectal abrasions and A.D.D.

[Anus2Mouth]

actually the sand itself can never get 'wet'. Like wetting a rock, only the exterior of the rock gets wet, never the inside of the rock. Sand is nothing more than little rocks. Put pressure on the sand and push away the fluid or H2O and the sand/rocks now have no water to be submerged in and, henceforth, appear dry. Aren't we a couple of fucking geniuses!

[darkness2k7]

o.O umm... if water hits the exterior of something it's consider wet, even if it doesn't go to it's interior. So yeah sand does get wet cause all those little rocks are getting wet.

[BkRoc]

its not all little rocks, you forgot the fish throwup

[UniqueLilBabi]

nice feet lol

[IGrazor]

I've never heard it referred to as the 'wet sand effect' but Reynolds' dilatancy has been known about since 1885. To the casual observer it does look like simple compression 'pushing the water out', but the final experiment shows a different mechanism in operation.

Psidot - Great videos, simple experiments like this are great for getting kids interested in science and apparently 're-educating' others that think they know all the answers. ;)

[C13GG]

Weird feet!!

[ClaudiaSwann]

this brilliant i always thought it would be due to the sand getting denser and the water being pushed away or something :S

again. interesting.

tnx

[CreamPie9uy]

so it gets 'bigger' under pressure? curious

[bashibazouks77]

i had that experience in pahang malaysia. only better,!

[callmeyang]

Thanks.

[MatthewCrump99]

ok thats 2 i know the wet sand one and the walking on custard one!

[rydude998]

OMG you ppl are so dumb, whats happening isnt "The Wet Sand Effect"...whats happening is when your feet hit the sand full of water the pressor pushes the water out of the sand beneath your feet....my god, what a stupid name to give it....

[OGMO11]

I was thinking the same