What is the difference between pressure and energy?

  • Context: High School 
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Discussion Overview

The discussion revolves around the concepts of pressure and energy, exploring their definitions and relationships. Participants seek to clarify whether pressure is a form of force or energy, using examples such as compressed air tanks and balloons to illustrate their points.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether pressure is a force or energy, expressing confusion about its nature in practical examples.
  • Another participant defines energy as the ability to perform work and explains that the gas exiting a tank or balloon has kinetic energy and exerts a force, but is neither energy nor force itself.
  • A different participant introduces the idea that pressure can be viewed as energy density, referencing the Bernoulli equation for further explanation.
  • Another example is provided comparing two balloons of different sizes but the same pressure, suggesting that while they have different energy potentials, their pressure remains constant.
  • One participant discusses the relationship between force, pressure, and area, indicating that a larger area would require more force to maintain the same pressure.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between pressure and energy, with no consensus reached on whether pressure should be classified as a force, energy, or a different concept altogether.

Contextual Notes

Some definitions and relationships between pressure and energy remain unresolved, particularly regarding the implications of pressure as energy density and the conditions under which these concepts apply.

Hypo
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Hallo everyone!

Im new here on this forum and I had a few questions in mind I would like to share them with everyone to get a perfect understanding with what I'm dealing with.

Now what is Pressure exactly? Is it a force or energy? I am kinda confused about it...?

For example the pressure from a compressed air tank blowing out through a small spot is that energy or force coming out?

Another example a balloon having a very very small poked whole to it... The air coming out from the pressure is that energy or force?

Thank you everyone :)
 
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Energy is the ability for one system to perform work on another system. A compressed gas or a balloon has the ability to perform work on the gas outside by releasing it's own compressed gas. The gas has lots of kinetic energy as it exits the tank/balloon thanks to pressure generated by the compression inside the tank, or the squeezing by the balloon. So to answer your question, it is neither energy nor force coming out of the tank or balloon, it is gas molecules that are in motion which have energy and exert a force on other molecules.

The definition of pressure itself is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.
 
Consider a second balloon, twice the size of the first, same pressure. It has twice the potential to do work (energy), but the same pressure, so they're different things.

Consider a vessel of compressed gas with a bung in the top. A wide bung would be hard to keep in because its area is larger. Force = pressure times area.
 

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