When Water Flows Uphill [video] (2013) | Hacker News Reader

When Water Flows Uphill [video] (2013)

youtube.com

245 pointsColinWright39 comments

"The difference between science and screwing around is writing it down"

-- Adam Savage

The importance of documentation

If you like watching water flowing uphill, I highly recommend paying this spot in Taiwan a visit [1]. It’s a very clever and convincing optical illusion.

1. https://eng.taiwan.net.tw/m1.aspx?sNo=0002016&id=A12-00284

Xenses Park near Cancun, Mexico, also has a great illusion with water appearing to flow uphill - it's very disorienting: https://youtu.be/c8v_CJtYjCI (Water mentioned around 2:10)

Nothing to do with the Leidenfrost effect, just interesting!

Throughout the video I was wondering what possible practical applications there could be. I got it at the end: "we use this effect to engage people who are otherwise not so interested in science".

I wonder if this could be used as the opening scene of a persuasive documentary on vaccines, it's pretty mesmerizing. Maybe an innocuous "How does it work?" theme with 10 phenomena, with one of them being vaccines.

It is still best to help the ignorant leading it to not being mesmerized.

When it comes to vaccines in a comprehensive scope, I suspect there is no Human that is not at least somewhat ignorant (or not all knowing), and delusional to at least some degree. The "science" aspect is but one part of a much more complex picture.

So let us have awareness campaigns, and make them unassailable by being perfectly honest - instead of furthering attempted manipulation ("mesmerizing people for persuasiveness through innocuous documentaries about the wonderful") as if it were aproblematic behaviour, and as if normal actually-adults would not be consequently exposed to dubious campaigns, with dubious results.

I do not know about many places around the world, but in some areas it is normally told to children in primary school that "well, before these milestones you had an important risk of measles or poliomyelitis" - just as part of the history of science and achievements, primary school level. Which again suggests that treating people like adults - even very "underage" - remains an important recipe to obtain, in the end, Adults.

To my thinking, a documentary that competently critiques folks on "both sides" of the argument would be an interesting strategy to try. As a conspiracy theorist myself, I think my idiot brethren might be able to open their minds a bit and be more reasonable for a change under those circumstances.

Thoughts?

Could be used to win bets for free drinks in a bar, shame you'd probably get kicked out for wielding dangerously hot metal plates before you've had a chance to drink them.

Never a good idea to drink hot metal plates

But how are you supposed to drink them when they are cold and solid?

Maybe in emulsion?

Earlier in the video they say it could be used to cool microchips.

Seems like a stretch... the examples in the video were around 400-500F

You just use a liquid that boils at a lower temperature

That's an i9 chip without proper cooling.

If we somehow ended up extinguishing gravity and we start floating upside down. Good to know we can now post water upwards.

Although thinking about it, water would float upwards too..

Water flows uphill all the time - all you need is an Eddy (https://en.wikipedia.org/wiki/Eddy_(fluid_dynamics))

I was just going to say, go to the beach. It's wind rather than steam providing the motion, but similar.

Watch the waves roll up the sand slope!

The practical way to get water to flow uphill is of course the https://en.wikipedia.org/wiki/Siphon - always amazing in its own way.

Which works in a vaccum as well.

(Periodic Videos): <https://www.yewtu.be/watch?v=8F4i9M3y0ew>

Barely related, but in Bern Gerechtigkeitsgasse they made an almost hidden art installation so that the Stadtbach (city stream) flows uphill in a small part. It's very fun to watch.

https://de.wikipedia.org/wiki/Stadtbach_(Aare)

How does it work?

"The city stream is redirected in an underground, invisible loop so that it flows backward, or upstream, for a short distance. However, the backflow is always just outflow in reality. This is because the watercourse has a continuous gradient." (translated from a Google result excerpt of this paywalled article [0])

[0] https://www.derbund.ch/warum-der-stadtbach-aufwaerts-fliesst...)

Yes, that seems to be the explanation. I found a few pictures here: https://www.komoot.com/de-de/highlight/615007 but they also do not show how it works.

If you enjoy this bit of physics, and you're wondering if water flowing the "wrong direction" is something that happens in real life, aside from the other comments about wind-induced counterflow, definitely look up the Severn bore[1], too, which is a tidal bore that makes the river Severn flow inland twice a day, with wave fronts that can be large enough for folks to "surf upstream".

[1] https://en.wikipedia.org/wiki/Severn_bore

I remember watching those little droplets form and bonce arond on the old solid stove tops we had when I was a kid, I loved it!

Heat engines are cool. (These are an example of a heat engine: something that converts thermal energy into mechanical work)

The Leidenfrost effect is also one explanation often given for why walking on hot coals without burning your feet is possible. The theory is that the sweat on your feet evaporates creating a vapor barrier that insulates the feet from heat.

Huh, this a a solved problem. You can walk on coals because both the ashy coals and your skin are poor conductors of heat, your feet are only in contact with the coals briefly, and your blood flow carries the heat away from the contact points. The only trick is to walk gently yet quickly on them.

Not getting any coals caught between your toes is a big one too. Walking with cramped feet is a great way to pick up coals ;P

The grooves at ~2:56 [1] are a result of the machining process?

[1] https://youtu.be/zzKgnNGqxMw?si=0Qlrd-lcyAUvJHg8&t=176

The water ball maze at the end is really cool.

It's technically a labyrinth rather than a maze as there's a single path.

It just needs a Minotaur.

I remember watching that video. About 10 years ago. Fascinating then, fascinating now.

The title should include that it is from 2013.

Reply on news.ycombinator.com