Basically, the conservation of energy can be summed up in the First Law of Thermodynamics, arguably one of the most important laws in physics. This law gives us the quantitative relationship between work, heat, and internal energy. Watch the video to first review what thermodynamics is and to learn about the First Law of Thermodynamics.
Question
When are the values of Q and W positive? When are the values of Q and W negative?
Q is positive when heat is added to the system. Q is negative when heat is lost by the system (or the surroundings gain it). W is positive when the system does work on the environment and negative when work is done on the system.
