>> ^HenningKO:
Ah, so they're not falling through space... they are falling toward Earth as is the camera. Perhaps in a vacuum.
What I thought of immediately was the gravity of the sand particles themselves attracting each other, in the absence of any other force. Like, how planets form on a larger scale. But, nah, it looks like it's time-shifted and the attraction is happening way too fast for that.


They are not falling in a vacuum, but I understand now that the title may appear a bit misleading. Sorry about that.

"The Lotus effect refers to the very high water repellency (superhydrophobicity) exhibited by the leaves of the lotus flower (Nelumbo). Dirt particles are picked up by water droplets due to a complex micro- and nanoscopic architecture of the surface which enables minimization of adhesion. The self-cleaning property of superhydrophobic micro-nanostructured surfaces was discovered in the 1970s and has been applied since the 1990s in biomimetic technical products."

via http://en.wikipedia.org/wiki/Lotus_effect

I like Asmo's suggestion that there was, for a brief moment, a cooled skin of aluminum over the water droplet, which allowed the steam pressure to build up. That might also explain the metallic "ping" when it pops.

I'm thinking water droplet too. It's quite plausible that they didn't dry the mold well enough after cleaning it.

Looks like a water droplet in the mold. They probably cleaned it very carefully before hand, but didn't heat it before pouring the aluminium in. Could be air expanding too, but water changes volume a hell of a lot more than air and would produce the reaction seen (I think water vapour is 1000 times greater in volume than liquid water). it's the violence of the expansion that causes the sound and the splattering metal.

I very much doubt the mold itself changed shape, it's a proper mold with think walls.

Does no-one else find it amazing that it takes them so long to figure out how to put the fire out?

Very Interesting I'm shuwa. (But I quit after: "Comes from the glowworm's mouth, and is loaded with droplets of mucus.) :>

^ Completely agree, they got viscosity all wrong, the fluid seems to stick to objects in weird ways and the momentum seems all wrong, watch near the beginning as a seemingly small velocity flow climbs all the way up the side of the wall, despite plenty of open space for it to slosh out towards the camera.

http://www.videosift.com/video/CG-Liquid-like-youve-never-seen-before-Amazing

This is a great example of good CG fluids, but I'm assuming it isn't real time. Still, something like this is the goal as far as I'm concerned, here it seems like the focus is on light reflecting off the water and maybe droplet creation/motion, but to me water looks more real when it flows correctly.

Tags for this video have been changed from 'waves, bubbles, chemical, physics' to 'waves, bubbles, chemical, physics, sphere, droplets, gravity, micro, zero' - edited by MarineGunrock

Every atom has a tiny tiny charge associated with it.

Actually, over 99.9% of the water particles in a bucket at 20,000 volts have a neutral net charge, because charge is quantized. If every water particle had an extra electron, it couldn't even condense to form a liquid.

flux effect of charged particles (ie. an EM field)

An electrical potential gradient is a more specific term for the kind of EM field present in this problem. The magnetic component is negligible.


Once the charge is large enough, the random distribution of the charge within the system is what creates the diffusion of the water dropping through the buckets.

You mean the positively charged water molecules repel other positively charged water molecules, etc.


Its basically a van-de-graffe machine, only in a really novel way.

A Van De Graaff machine is based entirely on surface friction, while this is based on electrostatic induction.

Zero kinetic / gravitational potential energy is converted, the meer useage of gravity is a neat way to get the water droplets to pass through the rings, but none of this energy is converted into electrostatic energy.

Even the site you linked contradicts you and agrees with me on this count. The energy for the sparks comes from the gravitational potential of the water in the source, since gravity does work to pull the positively charged water away from the negatively charged bucket and towards the positively charged bucket, etc.

Sorry to burst the bubble, but this is a dupe:

http://www.videosift.com/video/10000-Volt-Arcs-Created-by-Falling-Water-Droplets

Why did you downvote my comment ?
This has nothing to do with gravitational potential energy at all, its purely the interaction between positive and negatively charged water particles passing through a conductor to build up charge.

Zero kinetic / gravitational potential energy is converted, the meer useage of gravity is a neat way to get the water droplets to pass through the rings, but none of this energy is converted into electrostatic energy.


Edit: A more detailed description can be found here.
http://amasci.com/emotor/kelvin.html

The droplets don't actually mix... if you looked down from the top you would have seen concentric rings of color

If I had to guess, I'd say that this happens due to the same principle that causes grain elevators to explode from fine dust in the air. Any sufficiently flammable material, if it is in small enough particles and exposed to air, will combust. You can do it yourself by blowing a handful of flour into a candle flame. The only difference is you are generating a spray of droplets of flammable liquid, rather than flammable dust.

Well. Fist of all I'm the owner of the video, and yes, I own the mercury and I have it here in my room.

As for mercury vapour, yes, inhalation of this is the most dangerous thing, ingestion is not quite as dangerous since body cannot digest it, and skin contact is the least of the dangers, because of its density mercury can't be absorbed by the skin.

As for the zippo coments, well, there's no problem since the surface tension and density is so high it wont go inside of the lighter itself (it would be different if it was submerged, since the high presure it generates will force it's way inside.

No, i'm not Portuguese, I'm from Mexico.

I've had this bottle of mercury for years now, and no, i don't leave it open (or just laying in the box as in the video) all the time. It had been years since I last opened the bottle to mess around and I decided to record it to avoid doing it again.

And I am aware that small droplets might be spilled around some places, but the quantity of vapour they might produce until they dissapear is extremely low.

Mostly, people that get poisoned by mercury get this because of chronical exposure, this means large quantities of mercury that produce large quantities of vapour and ppl are exposed to it for years. Sure it would be dangerous to spill the whole bottle in the floor, or in a piece of furniture, since it's a lot of mercury, but no, I repeat to you it is on a sealed bottle.

One cool thing about mercury is that if you blow your breath into it it will get misty, just as if you were doing it to a mirror, next time you have the chance to play with mercury (even a small drop) try it

Thanks for watching anyway!

You're all welcome to see this other video I made documenting surface vibrations of that same mercury being exposed to low frecuencies... kinda cool...

http://www.youtube.com/watch?v=G2ZVz8rM8lY

I almost forgot, here's another demo showing frozen Mercury, (at least freezing it wont produce as much vapour) First a small dropp gets frozen, then a larger amount is frozen. Hope u like it.

http://www.youtube.com/watch?v=0-K5buIxuUY

When I was a kid we had a nice bottle of mercury that my father had purloined from his father's chemistry lab.  It is really, really fun to play with!

I must have spent many hours overall fooling around with it -- even spilling a fair bit, where the droplets must have gradually evaporated out of the cracks in the floorboards....

And I'm still completely *twitch* normal.

*twitch*