# First Law of Thermodynamics

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E system = E surroundings.

I can't make sense of this, can someone explain this to me? Is this saying that all forms of energy are equivalent?

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it says that energy diffuses. if you take a cubic foot of space, for example, it will have the same amount of energy in it as the cubic foot of space adjacent to it. if there is a heating source, for example, closer to the adjacent cubic foot of space, of course, it will have more energy in it, but this energy will immediately spread out over the universe.

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hmm yea i get what your saying but it doesnt mention that the surroundings start with the same energy as the system..... i mean what if its an isolated system?

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Like a vacuum flask, but that in time will be the same lol. I love a flasks, such a good thing!!! warm coffee on a walk about.

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IIRC, one can write the equation for the first law of thermodynamics as:

$\Delta E_{sys} = -\Delta E_{sur}$

Which means that energy is conserved; if the system gains energy, it comes at the expense of the surroundings, and if the system loses energy, the surroundings take up the lost energy.

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As Yggdrasil points out, the First Law is nothing but a restatement of energy conservation.

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