Expansion work/ Compression

[aphung1E]

for expansion do you need to include a negative sign when calculating values
what about compression?

[Hiba Alnajjar_2C]

When expansion takes place, work is being done and is therefore negative. When compression takes place, work is positive.

[kristi le 2F]

Remember that the sign for work is always in regard to the system. In expansion, the system is doing the work and is therefore losing energy so work is negative. In compression, work is being done on the system, so work will be a positive value.

[Uisa_Manumaleuna_3E]

Expansion and compression both denote work, but they exert that work in opposite directions. It helps me keep in mind the visual of a balloon expanding and deflating. Both require a change of energy or movement, but one obviously has a positive growth and the other a negative.

You just have to remember that when an object does do work (balloon expanding/expansion) that object or system LOSES that energy so its a negative.
When an object undergoes compression (balloon shrinking/compression) that object has work acted on it by something else so it GAINS energy and is positive.

[Abby Soriano 1J]

Things like work and heat should always be approached from the point of view of the system. Just as when heat is being applied to a system and delta H is a positive value, when work is being done on/to a system, the value of work is positive. When the system is doing work to its surroundings, work is negative.

[stephaniekim2K]

During expansion, work is being done so you need a negative sign while compression you need a positive sign.

[Kennedi2J]

w = (+) when work is done on the system (compression)
w = (-) when work is done by the system (expansion)

[Veronica Lu 2H]

negative work means work is being done (expansion) whereas positive work signifies work is done on the system (compression)