Videos you know you'll never use. (now SFW)

Stormtroper

What's going in the original video of that freak out at 2:22 in the second video?
Also:

glennmagusharvey

glennmagusharvey

lrdgck

glennmagusharvey

hey look i found a livestream

https://www.youtube.com/watch?v=JyrbqiCokdw

Stormtroper

lrdgck

^ I saw this video to the tune of Yakety Sax.

glennmagusharvey

This last one is quite (to use GMH's language) "spicy" for me and I wouldn't post it if it weren't the funniest thing ever;

Well if that is fair game then the following (which is arguably even less "spicy") should be.

https://twitter.com/JoeBiden/status/1307491919384260609

fourteenwings

which is arguably even less "spicy"

Was not spicy at all.

Though that should be expected when it's not the Harris Administration w/Joe Biden (is it just me or would that make a good band name?).

glennmagusharvey

I'm not sure what flipping the names around is supposed to mean there.

fourteenwings

glennmagusharvey

hahaha

Stormtroper

glennmagusharvey

Apparently someone made US GDP and globally-averaged temperature versions of this too, lol.

Edit: found one and two versions of it using crude oil prices.

Also, this one, which uses a different intro tune, but has colored subtitles, for fun:

glennmagusharvey

lrdgck

glennmagusharvey

Florida Man acts out Steamed Hams

Stormtroper

Edit: Embed is not working, have a link: youtube (dot) com/watch?feature=youtu.be&v=OMB6lVXtP4Q

glennmagusharvey

I think you need the video code directly following the question mark.

lrdgck

Folks in the comments say getting it to work is tricky, so you may want to read them.

Stormtroper

I was meaning to quiz you all at some point on IJBMer Updates on whether a fluid's pressure increases or decreases when passing through a nozzle, but the video spoils it.
In fluids mechanics class the prof. stumped us with that, we thought it'd increase, as you'd say in common parlance (or from putting your hand in the path of a hose's squirt then playing with putting your finger on the tip), but nope, and in hindsight it's obvious why (conservation of energy). Ever since I've wondered if it's a language issue, since I've never heard it it any language besides Spanish, so I thought I'd ask.
Regardless, new subscription.

glennmagusharvey

Would it be more correct to say that the pressure on the sides of the channel?

Because the increased velocity means that the pressure against a surface (or mathematical component of a surface?) orthogonal to the flow would increase, because their momentum change is greater resulting in greater force per unit area against whatever's blocking it, such as your finger.

lrdgck

Also, another find of today:

Stormtroper

^^ You mean as in the hand example? The term for that is dynamic pressure, and yeah, it increases.

glennmagusharvey

What's the other kind of pressure? Hydrostatic pressure?

Stormtroper

Static pressure.
That made me curious about the difference between static pressure and hydrostatic pressure, I had to look it up (molecules hitting surfaces vs. specifically the columns of water thing).
Edit: If you're wondering the sum of both is called stagnation pressure, "stagnation" meaning how a fluid would be if it were to be slowed down in some ideal way.

glennmagusharvey

Note I don't actually know the difference between dynamic and static pressure, though the names give me a vague guess that dynamic pressure has to do with macroscopic movement of a thing against something else whereas presumably static pressure is simply the pressure of something simply being there.

Stormtroper

I think you've got it. Static pressure is what we usually just call pressure, including the prof's question above, it refers to the force-by-area that would be excerted by molecules bouncing off surfaces around the fluid*, it's a thermodynamic property, while dynamic pressure is the "pressure" contributed to by the fluid's macroscopic speed, the extra push it would have on surfaces normal to its flow.
* Note: gases are fluids.

lrdgck

Here's some simple stuff I've fed my students if you are interested in more fluid mechanics. (I think I haven't posted that before.)

Stormtroper

I loved that explanation with the scales, even if you know about hydrostatic pressure it requires some thought as to where the water's weight "goes to".
Also Wikipedia has a chart on ground pressure that I thought was interesting, I thought it was surprising that war tanks have so low ground pressure (until you remember that they have to, otherwise they'd sink, as it used to happen in early models). Also it never occurred me that you can figure out the contact area of a pneumatic tire and similar (deformation on spheres/cylinders is tricky) by knowing its pressure and the force the surface excerts on it.
Also the other day I learned that a lot of people have the misconception that it's a misconception that rooftop water tanks hold water.