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Inspire kids to become scientists by saying that…..…………………………………………Darwinian evolution is an entropic phenomenon.

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The Second Law of Thermodynamics says that all complex things in a closed system like our universe will grow less complex, until everything is a cold soup of individual particles, unmoving. Time itself will effectively stop.

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The Universe is a closed system. There is no energy bleedover from or to other universes that might exist.

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The Universe is a simple system because it encompasses all that is.

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Energy enters and leaves the Earth all the time. Order can and does increase in such a local area. Complexity can arise from less complex things.

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Entropy is not a measure of randomness or disorder.

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The law of entropy is better read as “there is a high probability that entropy always increases”. It’s not physics, but probability that governs this.

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Entropy can decrease. It’s highly improbable but not impossible.

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The conservation of energy demands, that the speed of a thrown up ball must slow down as it gains height. When it loses height the speed increases. But alas! Some of the energy is given to the air molecules, but on it’s way back, the air molecules don’t give back the energy, so the situation is not really getting reversed.

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The conservation laws don’t tell why things change in a particular manner as time moves forward. It turns out that there is nothing special, it is just a game of probability.

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Due to probability, it’s more likely that coins starting with ‘all heads up’ after flipping becomes ‘some heads up and some heads down’ and the reverse (although allowed by the rules of physics) is highly unlikely (but not impossible).

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There is only one way to get the ‘all heads up’. Hence it is the lowest entropy state. There are 252 ways to get the ‘5 heads up and 5 tails up’ . It’s maximum entropy state.

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Say you have 100 trillion coins. After flipping them all, you will get about half a trillion H and half a trillion T. We might have a few 10’s of billion extra H, but overall it’s a tiny fraction and can be neglected. This explains why locally entropy could decrease, but globally it always increases.

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Entropy is not really about energy, it’s about no. of ways in which you can arrange something.

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More concentrated energy means lower entropy. More distributed means higher entropy. So concentrated energy tends to get more distributed over time. Living things exist because they are excellent at distributing energy of universe.

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Since our universe has grown, there is more room and hence more no. of ways to arrange the stuff. Hence the universe is growing in size and entropy.

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Since things are always changing in the higher entropy direction, we can distinguish between forward and reverse time.

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There might be changes happening locally .Only over all it’s pretty much half trillion H and half trillion T. However on a universal scale, there wouldn’t be any changes happening, and time would cease to exist.

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Entropy is how much energy in a system is unavailable for anything useful. Energy, on the other hand, is the ability to actualize changes to a system; the amount of energy in a system is the total amount of changes that can be made to it.

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The total amount of changes that can be made to a system (which is hypothetically infinite) is conserved; can’t increase, can’t decrease, etc. Entropy increases because all of that energy is becoming more and more unavailable for mechanical purposes.

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