The hydrostatic pressure at the surface is the atmospheric pressure, yes. Not at the bottom, I'm not an idiot. So in your fantasy siphon, you have 100 kPa pressure (absolute) at the surface, then 10 m higher, you have 0 kPa pressure, then 10 m further up you have -100 kPa. Oops.

Indeed, the difference in pressure is independent of atmospheric pressure. The only problem is that at the base of the column, the hydrostatic pressure equals the atmospheric pressure. Oh and you're not allowed to have a negative pressure!

and where do you think the hydrostatic pressure is from? You seem to be saying that I could build a siphon that starts at the top of a building, bring the pipe all the way up to the edge of space, then back down to the bottom of the building and the siphon would work fine? In any column of liquid of height h, with density rho, the change in hydrostatic pressure between the top and bottom of the column is going to be equal to rho*g*h (g=9.8 m/s^2). This is why for water, if you start with 1 atm and go up 10 m, you have zero hydrostatic pressure left. Beyond that you'll get a bit of surface tension, and then if you keep going up, your column will split unless you have some other force.

At 9 m high, the column of water can't break because that would create a vacuum and the atmospheric pressure of ~100 kPa is enough to push a column of water up to 10 high. OTOH, at 11 m, you'd end up with vacuum and two columns. It's the same reason you can't drink water from an 11m high straw, even if you have really powerful lungs. In any siphon, you need gravity to get the liquid to move, and you need some other force to keep the columns of liquid from separating around the highest point. That force can be atmospheric pressure, or it can be attraction between the molecules themselves (aka surface tension). At one point, any of these will break, or are you saying you can build a siphon that goes 100 km high?

I'm not saying it's about hiding something, just about demonstrating up to the level where the thing will work. I don't know how strong the surface tension is exactly. What I do know, is that atmospheric pressure is sufficient to have a siphon that's 10 meters tall and I very much doubt that surface tension comes even close to that value. I'm sure your friend would be able to calculate how high it goes, but I doubt that's more than a few cm high.

...and the former still being essential because if you lose cohesion you have two separate columns and nothing flowing.

Atmospheric pressure is what provides the cohesion in the normal case of the water siphon. It means you can in theory have a siphon that climbs up to 10 meters. The experiment in the video indeed does not use atmospheric pressure. It relies on surface tension, which is much weaker. Even if water didn't boil in a vacuum the siphon would work only work for a height around a mm or so (high high can you "pull" water using its surface tension?). The liquid used in the experiment has a much higher surface tension than water, which is shy the siphon works at all. That being said, I doubt it would work for much higher than what was shown in the experiment -- if it did, the experimenters would have shown us a more impressive siphon.

In this case they rely on surface tension, and while it works at a few cm height, I doubt it would work for a 1 meter siphon.

Atmospheric pressure isn't enough, but it's still required. In this experiment, 0.18 atmosphere is just enough for (in theory) a 1.8 meter siphon, had the guy attempted to get it to work at 2 meters, it would have failed because the atmospheric pressure needs to be high enough to hold the column of liquid.

As far as I'm concerned, the message should be:

"Here's the only link between vaccines and autism: if you don't vaccinate your children, they might die before they can even be diagnosed with autism."

Good, then you can make use of almost 16 bits!

Now only is 192 kHz/24 bit silly in general, it's even more silly for a portable music player, that's usually used in places with a higher background noise than your living room. Listening to music above 100 dB SPL in a cafe with noise at 50 dB SPL means you only need an SNR of 50 dB, just slightly more than 8 bits.

Consider this, if an electron were to transition from "really far" down to the first energy level of the hydrogen atom, then the photon emitted would have an energy of 13.6 eV, and the mass of the resulting hydrogen atom would be 13.6 eV less than the sum of the original masses.

Sorry, I meant to say 511 *keV* for the rest mass of the electron.

Actually, the mass of a hydrogen atom isn't equal to the sum mass of the proton and that of the electron. There's a 13.6 eV binding energy (good 'ol E-mc^2) that needs to be taken into account. Considering that the 511 eV rest mass of the electron and the fact that we're taking about measurements that are supposed to be accurate to less than 1 part per billion, then the binding energy is pretty significant. I suspect there are other effects that also need to be taken into account.

More generally, any device that lets energy (light, sound, heat, ...) only flow in one direction has to spend energy to avoid violating the laws of thermodynamics. That's true of this device just like for a heat pump. You could probably also create a real one-way mirror, but again it could not be a passive device and would require energy to operate.