What are the 1st and 2nd law of thermodynamics?

Answer 1

The first law is that energy cannot be created or destroyed. Any process can only convert energy from one form to another. Einstein's famous equation E=mc2 extends this to include conservation of energy AND mass and explain the source of the energy released by nuclear fusion.

The second law can be phrased a lot of different ways:

• energy always flows from higher temperature to lower temperature
• the entropy of the universe will always increase
• in any natural process, some energy will be lost to heat rather than converted to useful energy
• any time you convert some energy to work, you will also lose some of the energy to heat
• ... and a lot of others

My personal favorite way to capture the 2 laws is:

First law: you can't get something for nothing

Second law: not only that - you can't even break even

Answer 2

The first law of thermodynamics states that you can't create or destroy energy.

The second law of thermodynamics has been formulated in several ways; one of them is that useful energy is constantly being converted to useless energy - in other words, with respect to energy, there are irreversible processes in nature. Another way to phrase it is that heat only flows from higher temperature to lower temperature spontaneously. To move heat from a low temperature to a higher temperature, you must do work - that's why you have to plug in your refrigerator and your power bill is higher during the summer when you run your air conditioning.

Answer 3

The First Law is equivalent to Conservation of Energy.The Second Law can be stated in many different (and equivalent) ways; one way to state it is that useful energy will be converted into unusable energy. In other words, irreversible processes occur all the time.