Violation of conservation of energy?

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SUMMARY

The discussion centers on the principle of conservation of energy (COE) in relation to the behavior of a compressed spring. When a spring is compressed, it gains potential energy, which some participants mistakenly interpret as an increase in mass, suggesting a violation of COE. However, it is clarified that COE holds true in closed systems, where no energy crosses the system boundary. If external forces, such as a human compressing the spring, are included in the system, the energy gained by the spring is balanced by an energy loss from the external source, maintaining the validity of COE.

PREREQUISITES
  • Understanding of the conservation of energy principle
  • Basic knowledge of potential energy in mechanical systems
  • Familiarity with closed and open systems in physics
  • Concept of mass-energy equivalence (E=mc²)
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Ameer Bux
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By squeezing a spring until it coils up, it then has more potential energy. So it will then have more mass, because mass is energy. So doesn't that violate the law of conservation of energy. The spring has more energy and mass after its squeezed than when it wasn't squeezed?
 
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It takes an external power source to increase the energy and mass of the spring.
 
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Ameer Bux said:
By squeezing a spring until it coils up, it then has more potential energy. So it will then have more mass, because mass is energy. So doesn't that violate the law of conservation of energy. The spring has more energy and mass after its squeezed than when it wasn't squeezed?

Conservation of energy only holds for a "closed system". That is a system that has no energy crossing the system boundary.

If your system boundary only contains a spring then no energy can get in or out so the spring cannot be compressed and COE holds true.

If your system boundary includes something (like a human) that can compress the spring then any energy gained by the spring is matched by an energy loss from the human - and once again COE holds true.

If you ever see an experiment that appears to violate COE it probably means you have forgotten to include something within your system boundary so it isn't closed (eg some energy is leaking into or out of your system).
 
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