What does atmospheric pressure have to do with the gauge pressure?

[Callmelucky]

Homework Statement:

Please explain if you want/can, thank you.

Relevant Equations:

P = F/A
P(total) = P(gauge) + P(atm)

In this video( ) it's explained what is gauge pressure.

Can someone please explain to me what does atmospheric pressure acting on a tube(in video at 3:51) has to do with displacement of a tube?
I understand that the atmospheric pressure acts on the tube, but in the open space that does not cause the tube to move, it just causes pressure on both ends of the tube, therefor no movement.
So if there was no pressure inside the tire that was greater than atmospheric pressure the tube wouldn't move.

I can understand that gauge devices work if they have some kind of spring inside them that takes of atmospheric pressure from total pressure which is 1.033 kg/cm2 at the sea level. But I don't understand how atmospheric pressure does that by himself(as he said in 3:51 "the atmospheric pressure pushes back on the tube")

Thank you.

 

[hutchphd]

My advice is to never watch this video again.

 

[256bits]

Homework Statement:: Please explain if you want/can, thank you.
Relevant Equations:: P = F/A
P(total) = P(gauge) + P(atm)

I can understand that gauge devices work if they have some kind of spring inside them that takes of atmospheric pressure from total pressure which is 1.033 kg/cm2 at the sea level. But I don't understand how atmospheric pressure does that by himself(as he said in 3:51 "the atmospheric pressure pushes back on the tube")

Well I guess he over simplified in his quest to explain gauge pressure.
and your right there would be a spring within the guage
Your ordinary pencil tire gauge looks like this inside.

On one side of the orange piston there is the force from the tire pressure.
On the other side is the force from the compressed spring AND the force from the atmospheric pressure.
If there was no spring the piston would more completely to the right end regardless of tire pressure.

 

[Callmelucky]

Well I guess he over simplified in his quest to explain gauge pressure.
and your right there would be a spring within the guage
Your ordinary pencil tire gauge looks like this inside.
View attachment 321531
On one side of the orange piston there is the force from the tire pressure.
On the other side is the force from the compressed spring AND the force from the atmospheric pressure.
If there was no spring the piston would more completely to the right end regardless of tire pressure.

Thank you.