Recent comments in /f/askscience

lichlord t1_j5wrrfh wrote

Was it thermo taught by scientists or engineers?

Thermo in chemistry and physics usually simplifies steam into gaseous water.

In engineering thermo courses the focus is less in phases and equations of state, and more on work and transformations. Engineering thermo will often distinguish between wet, dry, and superheated steam.

1

zephyer19 t1_j5wqthg wrote

Could ice be vibrated off the street?
My area is in the middle of Winter. An early snow went through typical periods of warming and cooling. Melting and refreezing.

Many of the streets now have hard packed ice with large grooves where tires run. Trying to turn a car can cause quite a bit of bouncing around. Intersections are often ice rinks. Of course, walking across the street is a bit dangerous.

Could a machine of some type cause the ice to vibrate hard enough to break its bond to the street? Perhaps shatter it into pieces for easy removal?

1

ggiesen t1_j5wpzs8 wrote

We know because we have randomized, double-blind studies and millions upon millions of doses and millions upon millions of infections. We know statistically you're far less likely to end up in the hospital or die from Covid if you're vaccinated, and have millions of examples to prove this out.

That doesn't mean you will never get sick or die from Covid if you're vaccinated, just that you're far less likely to, and as such, the vaccine works. All of these are well understood if you don't bury your head in the sand or fill it with extremist garbage.

Sure, perhaps we've come to expect too much from vaccines, like with the efficacy of things like the polio vaccine which has effectively eradicated the disease. We were all hoping for a silver bullet that can end the pandemic. But that doesn't mean the vaccine doesn't work or that we would be better off without it.

2

hogey74 t1_j5wp51a wrote

Because human space flight looks powerful but is actually super weak. The chemical reactions we use are dangerously powerful of course but compared to the physics of gravity, required reaction mass etc, they're barely enough to get us off the planet. Those Saturn moon rockets were the most crazy impressive things we'd ever made but NASA couldn't get us to and from the moon until they did things like remove the seats from the lunar module. That's how close it was.

And the amount of money being spent similarly is a lot yet is also barely enough. The US briefly hit 4% of GDP on the moon program, a massive effort for something other than a world war. It only happened because the space program was essentially a military operation that was an extension of WW2. Space mostly still is today.

In short, we can just barely do space stuff. Every gram and every dollar is tight.

You are not mistaken in the idea. It's doable and preferable for biosecurity etc.

−1

Angdrambor t1_j5wob3l wrote

>Steam is droplets of liquid water suspended in the air which appears white due to light scattering.
>
>Vapor is colorless and transparent. You cannot see it.

When I took thermo in my country, we refered to it the other way around. Steam is the invisible gas phase, "vapor" is the white cloud of liquid droplets.

15

Redwoo t1_j5wlw9v wrote

Steam is clear and colorless and is water vapor…water in gaseous form. Water vapor that condenses from its gaseous phase to its water phase is called condensed water vapor, or fluffy white clouds. Condensed water vapor consists of a multitude of tiny droplets of liquid water. Condensed water vapor converts to steam, invisible gaseous water vapor, if it is heated above 100 C.

The steam that enters a turbine at a nuclear plant is around 800 degrees F, depending on whether it is a pressurized or boiling water reactor. The white fluffy clouds of water droplets coming from the cooling towers at some nuclear plants is within several degrees of atmospheric temperature.

9

RhodesArk t1_j5wkzbm wrote

Ya, but it's not given equal between those two sectors. Some jobs are hyper specific, or have clearances, or are just specialized. Wage transparency is also variable, since most industries don't disclose and few jurisdictions require it.

The article is saying on a broad trend. I'm taking one sector out of context and being an internet contrarian.

1