i did a google search, and these bits from various places seem to explain it as simply as i've seen:
[size=+1]Energy exists in many forms, such as heat, light, chemical energy, and electrical energy. Energy is the ability to bring about change or to do work. Thermodynamics is the study of energy.[/size]
[size=+1]1st law of thermodynamics: Energy can be changed from one form to another, but it cannot be created or destroyed. The total amount of energy and matter in the Universe remains constant, merely changing from one form to another. The First Law of Thermodynamics (Conservation) states that energy is always conserved, it cannot be created or destroyed. In essence, energy can be converted from one form into another.[/size]
[size=+1]Second Law of Thermodynamics[/size]
[size=+1]Heat can never pass spontaneously from a colder to a hotter body. As a result of this fact, natural processes that involve energy transfer must have one direction, and all natural processes are irreversible. This law also predicts that the entropy of an isolated system always increases with time. Entropy is the measure of the disorder or randomness of energy and matter in a system. Because of the second law of thermodynamics both energy and matter in the universe are becoming less useful as time goes on.[/size]
[size=+1]Third Law of Thermodynamics[/size]
[size=+1]The third law of thermodynamics states that if all the thermal motion of molecules could be removed, a state called absolute zero would occur. Absolute zero results in a temperature of 0 Kelvin (or -273.15°Celcius). [/size][size=+1]The Universe will attain absolute zero when all energy and matter is randomly distributed across space[/size]