00:01
So if you recall, the first law of thermodynamics stated as an equation is that the change in energy is equal to the heat absorbed by the system plus the work done by the surroundings.
00:15
We have a state function and energy and two path functions in terms of heat and work.
00:21
But let's make sure we understand what heat and work really are.
00:27
So first, to understand heat, let's take a look at two different solids that share a common surface, and say we have one that has hot molecules, higher temperature, one that has substance at a lower temperature, sharing this common surface.
00:54
And so what's going to happen here? well, energy is going to get transferred from the warmer surface into the cooler side.
01:06
And that's going to happen because the kinetic energy of the hot molecules, if you will, have a higher vibrational motion than the cooler ones.
01:21
You can see that by the length of the arrows...