Pressure Demo: Magdeburg Hemispheres

This is a demonstration of the Magdeburg Hemispheres, which are two small hollow hemispheres that mate together well. When the interior of the resulting sphere is evacuated, the hemispheres are difficult to separate.

This demonstration was created at Utah State University by Professor Boyd F. Edwards, assisted by James Coburn (demonstration specialist), David Evans (videography), and Rebecca Whitney (closed captions), with support from Jan Sojka, Physics Department Head, and Robert Wagner, Executive Vice Provost and Dean of Academic and Instructional Services.

[GlidyBun]

Currently studying for my physics finals - this kind of stuff keeps me interested.

[matteoalran]

You seem to be such a good teacher, who gets everyone interested ! congrats

[HarisHameed-od]

He explained it very clear. His experiments keep me interested in Physics.

[thuynguyen]

Thank you so much for all of your valuable videos

[aarav]

Thank you for making me understand sir

[liskotori]

Thank you sir my physics professor brought me here

[angelmtz]

In the calculus, Why did you get pounds (lb) when you are expecting units of Force, like for example Newtons (N)?

[thelifeandtimesofjames]

So an old English long bow user (pulling a 200lbs bow) would be able to separate it then?

[jess]

01:54 - aren't you actually letting air back into the interior as the vacuum had already removed the air from the inside?

[chwngsir]

Can I embed part of your video in my Youtube clip for teaching? Please.

[shrejaltripathi]

I can really understand the topic because of your experiment

[DownhillAllTheWay]

At 0:45 - "Just imagine the air being sucked out of there" - well, yes - if you were looking at any other video - but in this video, rather imagine the air being pushed out of there by the remaining pressure of air (low though it may be) being higher than the pressure in the vacuum pump. That's why you can never get a perfect vacuum - because it always takes a bit of pressure to push the remaining air out.
OK - call me a nerd!

[AmitkumarYadav-sghe]

Sir if we do this process in space or by applying more force greater than atm then the sphere will open or not? In both cases

[joaosimoes]

I didn't understand the part of the area. Why isn't the area that couple the two halfs??

[kumudraj]

Why don't the hemispheres crush due to air pressure when there is no air inside? Pls help.

[abrarshahriar]

Sir, sometimes we find it's difficult to open a container lid..Is it because of the same phenomenon??That it creates a low pressure region(If it is then how is it created??).Probably it's not vacuum inside!!Right???Sir, I need help?? Help this miserable??Lol

[ShopperPlug]

I'm here in the year 2021, I can't even make such strong vacuum and how did they make such strong vacuum back in 1650 without special rubber seals or gaskets? legend says that 8 horses on both sides can't even pull that vacuum out... Non of this makes any sense without introducing the facts of its purpose and origins...

[henryfolds]

Great Video, but I feel sorry for you having to convert from imperial to metric!!

[matteotigani]

how is this accurate to the same experment back then they didnt have the vacuum

[maybeitstanish]

1:45 -_-
i am from 8th standard, i just caem here from a fun fact in our chapter ... and the formula is bouncer for me 😳😱🥵