 Now we're going to talk about a couple of concepts in thermodynamics called specific heat and latent heat. We're going to take a look at the equations and the variables for those two concepts. Specific heat is defined by the equation q equals mc delta t, and this is the heat required to change the temperature of a material. And this equation q stands for heat, and by that may mean the transfer of thermal energy. The standard unit for that is joules because it is an energy. Alternately, you'll see calories used, and one calorie is equal to 4.186 joules. And then this equation is the mass. It's the standard unit in kilograms, and sometimes you'll see grams. Delta t is the temperature change, and for any temperature change, that's going to be the final temperature minus the initial temperature. Now you can use Kelvin or Celsius for this, because the temperature change in either one of those temperature scales is actually equivalent to one another. But you cannot use Fahrenheit in this equation. And that leaves us with c. c is the specific heat capacity. This is a property of materials, which depends on what type of material you have. It also depends on what the phase of the material is. The standard units are joules per kilogram Celsius degree, although you'll also see calories per gram Celsius degree in some tables. Here's an example of a table you might see for specific heat. On this listing, it's going to give you the types of materials, and a lot of times you're seeing metals, so aluminum, beryllium, cadmium, copper, et cetera. And you'll have the specific heat value for each one of those. A few other materials, besides just some of those element solids, are listed over here, and you notice that we have ice here, ice being the solid form of water. They list a few liquids, because specific heat can be done on the liquid phase of the material as well, and alcohol, mercury, and water are listed. We don't normally deal with aluminum in a liquid form, so it may not be listed in the textbooks table, but there are other industrial tables that would give you the liquid forms of all those metals. Gases are a little bit more complicated, but they do go ahead and list here steam, which would be the gaseous phase of water. So you'll notice that we have the solid, the liquid, and the gas phase for water, and the specific heat for each one of those phases is a little bit different. Now we can take a look at latent heat. The general equation for latent heat is going to be Q equals ML, and this is the heat required to change the phase of a material. Once again in this equation, Q is heat, the transfer of thermal energy, and it has the same standard and alternate units. And mass is still what we're talking about with M, and it has the same units. Then we get to latent heat. Just like specific heat, this is a property that depends on what type of material you're dealing with, and it also depends on the phase. In this case, what phase change is happening? So in this equations, we end up with an LF, latent heat of fusion, if you're going between solids and liquids, or liquids and solids, and LV, the latent heat of vaporization, if you're going between liquid and gas, or gas stacked onto liquid. The standard unit is going to be a joule per kilogram. Notice it doesn't depend on the temperature here, because the phase change doesn't depend on the temperature change. And alternately, you might see a calorie per gram. Here's an example of a table of latent heat values you might find in a textbook. Latent heat of fusion is given in one column. The latent heat of vaporization is given in another column. For these ones, it gives the substances, but it also mentions the melting point and the boiling point. The latent heat of fusion always happens at that melting freezing point, and the latent heat of vaporization always happens at the boiling point condensation point. So it gives you the temperatures that those things happen at as well.