Thermodynamics is the part of physics that has to do with the relationship between heat and other types of energy. It describes how thermal energy is switched to and from other forms of energy and how it can affect things.
Thermal energy is the energy of an object because of its temperature, like the energy of moving molecules. Thermodynamics involves measuring this type of energy, which is extremely complicated. David McKee, a professor of physics at Missouri Southern State University, said "The systems that we study in thermodynamics … consist of very large numbers of atoms or molecules interacting in complicated ways. But, if these systems meet the right criteria, which we call equilibrium, they can be described with a very small number of measurements or numbers. Often this is idealized as the mass of the system, the pressure of the system, and the volume of the system, or some other equivalent set of numbers. Three numbers describe 1026 or 1030 nominal independent variables"
Thermodynamics has to do with a lot of properties of matter but the most important one, would be heat. Heat is a type of energy that is transferred between objects due to a temperature difference between them. As a form of energy, heat cannot be created or destroyed. But, it can be transferred from one place to another, and from one from of energy to another. For example, a light bulb can turn electrical energy to electromagnetic radiation (AKA, light) when this radiation is taken in by a surface, it is turned back into heat.
The amount of heat transferred from one thing to another, all depends on how fast and how many atoms are moving. So, the more atoms that are moving around in a fast pace, the more heat is trasferred. Tempertaure is most commonly measured in Celcius and sometimes in Fahrenheit, but they both do the same thing, its just up to preferences. When it comes to scientists measuring temperature, the use a different way of measuring it. Instead of the Celcius and Fahrenheit scales, they use the Kelvin scale because they can use that in calculations as well.
Newton's Law of Cooling
Sir Isaac Newton made his law of cooling and he stated it in a shor article called "A Scale of the Degrees of Heat." He had said that "the rate of change in temperature is proportional to the difference between the temperature of the object and that of the surrounding environment." So, in simpler terms if you were to place a very hot metal rod into an ice bath, the temperature of the object would decrease by half in a certain amount of time and then by half again in the same amount of time and the process keeps repeating until the hot object becomes cold.