Wouldn’t the Second Law of Thermodynamics violate the First Law of Thermodynamics?


The second law of thermodynamics states that entropy always increases, which means that if there was a point where there was heat inside a box, the heat would dissipate throughout the box. If we wanted to return all that heat to the original point, we would have to add energy to move the heat to its original point. Wouldn’t this mean that energy is lost when the heat dissipates?

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It’s being lost as *usable* energy. The total amount of kinetic energy is still there, but it can no longer be used to do things, it’s just there, making the room a bit hotter than it had been.

No, that heat energy is still there it just only flows in a single direction naturally.

Just like how things don’t fall up.

Heat dissipating doesn’t mean the energy is destroyed. Heat dissipating means the heat went from somewhere hotter to somewhere colder.

Entropy is the measure of energy in a system that isn’t useful anymore. All of the energy is still there, but in the high entropy state, that energy can’t be used to do work.

I like to use chocolate milk to explain entropy. You have the milk and the syrup (or powder) and if you kesve them unmixed, thats a low entropy state because it’s highly organized. If we stir up the chocolate milk, we still have the same stuff there, but it’s now all mixed up, and we can’t unmix it now. It’s in the high entropy state.

Imagine the chocolate being dissolved into the milk as the system doing work. Early on, we get lots of work out of the system, but once its all mixed in, we can’t do any more work because there’s no more chocolate and milk anymore, only chocolate milk.

No, because heat is just a different, less useful form of energy, so no energy has been lost, only transferred and distributed differently.