In order to answer this question, we must first understand what energy is. Energy is the ability to do work. It is present in all things, both living and non-living. It can be found in the form of heat, light, electricity, motion, and chemical energy.
The sign of the energy change is the direction of the flow of energy. For example, when you are doing work, energy is flowing from your body to the object you are working on. The direction of this flow is from you to the object, so the sign of the energy change is positive.
When you are doing work, you are increasing the energy of the object you are working on. This is because you are giving the object your energy. If the object you are working on is at a higher energy state than you are, then the sign of the energy change is negative.
In summary, the sign of the energy change is the direction of the flow of energy. If you are doing work, the sign of the energy change is positive. If the object you are working on is at a higher energy state than you are, the sign of the energy change is negative.
Other related questions:
Q: What is the symbol for change in energy?
A: The symbol for change in energy is ΔE.
Q: What does ∆ s mean?
A: The symbol ∆s represents the change in entropy of a system.
Q: What does it mean for an energy change to be positive or negative?
A: When an energy change is positive, it means that the system has absorbed energy from the surroundings. When an energy change is negative, it means that the system has released energy to the surroundings.