The Physics of Vacuums: Understanding Force and Gravity

  • Context: High School 
  • Thread starter Thread starter oneamp
  • Start date Start date
  • Tags Tags
    Force Gravity Physics
Click For Summary
SUMMARY

The discussion centers on the physics of vacuums, specifically the forces at play when using a straw to lift liquid. When the end of the straw is pinched, atmospheric pressure becomes the primary force counteracting gravity, allowing the liquid to rise. However, with a longer straw, the weight of the fluid column can exceed atmospheric pressure, causing the fluid to fall. Professor Walter Lewin's lecture provides an in-depth explanation of these concepts.

PREREQUISITES
  • Understanding of atmospheric pressure
  • Basic knowledge of gravity and fluid dynamics
  • Familiarity with the concept of vacuum
  • Knowledge of force and pressure relationships
NEXT STEPS
  • Watch Professor Walter Lewin's lecture on vacuum physics
  • Research fluid dynamics principles related to pressure and gravity
  • Explore the effects of atmospheric pressure on liquid columns
  • Study the limitations of suction in various straw lengths
USEFUL FOR

Students of physics, educators teaching fluid dynamics, and anyone interested in the practical applications of atmospheric pressure and gravity in everyday scenarios.

oneamp
Messages
222
Reaction score
0
What is the force associated with a vacuum? If I put a straw in a soda and pinch off the end of the straw, then lift it out of the soda, some soda stays. What force counteracts gravity?
 
Physics news on Phys.org
It is the atmospheric pressure that pushes the liquid up the straw.Since you reduce the pressure inside the straw the downward force on the liquid is only the force of gravity, the upward force due to pressure remains so the fluid goes up. If you try to do this with a very long straw you would reach a point where the weight of the fluid column is greater than the force due to the atmospheric pressure and the fluid would fall.
prof Walter Lewin did an amazing lecture on this here:
 
Last edited by a moderator:
  • Like
Likes   Reactions: 1 person
Thanks
 

Similar threads

Undergrad Blowing between two objects -- Why is the pressure low?
  • · Replies 76 ·
3
Replies
76
Views
12K
Undergrad Vacuum and pressure will it move?
  • · Replies 1 ·
Replies
1
Views
2K
High School How to characterize a rubber ball moving horizontally and bouncing off of a vertical wall?
  • · Replies 8 ·
Replies
8
Views
2K
High School Circular wire center of gravity
  • · Replies 9 ·
Replies
9
Views
1K
High School Why Is an Object's Weight Equal to the Force of Gravity It Experiences?
  • · Replies 51 ·
2
Replies
51
Views
5K
High School Why do objects break? (in the case of a body at rest on a surface)
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Please Explain Elementary Physics Elevator Question
  • · Replies 22 ·
Replies
22
Views
950
High School Coriolis problem - Point mass movement upon release from Earth
  • · Replies 81 ·
3
Replies
81
Views
8K
High School Newton's 3rd Law interactions with 2nd and 1st Law Partners
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Remark on centrifugal force in Heino Falcke's black hole book
  • · Replies 22 ·
Replies
22
Views
3K