[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:08.00,0:00:10.00,Default,,0000,0000,0000,,Say two people are walking down the street
Dialogue: 0,0:00:10.00,0:00:11.00,Default,,0000,0000,0000,,and they bump into each other.
Dialogue: 0,0:00:11.00,0:00:14.00,Default,,0000,0000,0000,,They'll just shake it off and walk on.
Dialogue: 0,0:00:14.00,0:00:16.00,Default,,0000,0000,0000,,Sometimes that happens with molecules too.
Dialogue: 0,0:00:16.00,0:00:19.00,Default,,0000,0000,0000,,They just bounce off each other and that's that.
Dialogue: 0,0:00:19.00,0:00:21.00,Default,,0000,0000,0000,,But what if two people were to bump into each other,
Dialogue: 0,0:00:21.00,0:00:22.00,Default,,0000,0000,0000,,and during that collision,
Dialogue: 0,0:00:22.00,0:00:24.00,Default,,0000,0000,0000,,one person's arm got severed
Dialogue: 0,0:00:24.00,0:00:27.00,Default,,0000,0000,0000,,and reattached to the other person's face?
Dialogue: 0,0:00:27.00,0:00:29.00,Default,,0000,0000,0000,,Now that sounds really weird,
Dialogue: 0,0:00:29.00,0:00:31.00,Default,,0000,0000,0000,,but it's similar to one of the many ways
Dialogue: 0,0:00:31.00,0:00:33.00,Default,,0000,0000,0000,,that molecules can react with each other.
Dialogue: 0,0:00:34.00,0:00:36.00,Default,,0000,0000,0000,,Two molecules can join and become one.
Dialogue: 0,0:00:36.00,0:00:39.00,Default,,0000,0000,0000,,One can split apart and become two.
Dialogue: 0,0:00:39.00,0:00:40.00,Default,,0000,0000,0000,,Molecules can switch parts.
Dialogue: 0,0:00:41.00,0:00:43.00,Default,,0000,0000,0000,,All these changes are chemical reactions,
Dialogue: 0,0:00:43.00,0:00:45.00,Default,,0000,0000,0000,,and we can see them happening around us.
Dialogue: 0,0:00:45.00,0:00:48.00,Default,,0000,0000,0000,,For example, when fireworks explode,
Dialogue: 0,0:00:48.00,0:00:49.00,Default,,0000,0000,0000,,or iron rusts,
Dialogue: 0,0:00:49.00,0:00:50.00,Default,,0000,0000,0000,,or milk goes bad,
Dialogue: 0,0:00:50.00,0:00:51.00,Default,,0000,0000,0000,,or people are born,
Dialogue: 0,0:00:51.00,0:00:52.00,Default,,0000,0000,0000,,grow old,
Dialogue: 0,0:00:52.00,0:00:52.00,Default,,0000,0000,0000,,die,
Dialogue: 0,0:00:52.00,0:00:54.00,Default,,0000,0000,0000,,and then decompose.
Dialogue: 0,0:00:54.00,0:00:57.00,Default,,0000,0000,0000,,But chemical reactions don't just happen willy nilly!
Dialogue: 0,0:00:57.00,0:00:59.00,Default,,0000,0000,0000,,Everything has to be right.
Dialogue: 0,0:00:59.00,0:01:01.00,Default,,0000,0000,0000,,First, the molecules have to hit each other
Dialogue: 0,0:01:01.00,0:01:03.00,Default,,0000,0000,0000,,in the right orientation.
Dialogue: 0,0:01:03.00,0:01:05.00,Default,,0000,0000,0000,,And second, they have to hit each other hard enough,
Dialogue: 0,0:01:05.00,0:01:07.00,Default,,0000,0000,0000,,in other words, with enough energy.
Dialogue: 0,0:01:08.00,0:01:09.00,Default,,0000,0000,0000,,Now you're probably thinking
Dialogue: 0,0:01:09.00,0:01:11.00,Default,,0000,0000,0000,,that a reaction just happens in one direction and that's it.
Dialogue: 0,0:01:12.00,0:01:13.00,Default,,0000,0000,0000,,Sometimes that's true.
Dialogue: 0,0:01:13.00,0:01:15.00,Default,,0000,0000,0000,,For example, things can't unburn
Dialogue: 0,0:01:15.00,0:01:17.00,Default,,0000,0000,0000,,or unexplode.
Dialogue: 0,0:01:17.00,0:01:20.00,Default,,0000,0000,0000,,But most reactions can happen in both directions,
Dialogue: 0,0:01:20.00,0:01:22.00,Default,,0000,0000,0000,,forward and reverse.
Dialogue: 0,0:01:23.00,0:01:25.00,Default,,0000,0000,0000,,There's no reason that our face-arm guy
Dialogue: 0,0:01:25.00,0:01:27.00,Default,,0000,0000,0000,,can't bump into armless girl,
Dialogue: 0,0:01:27.00,0:01:30.00,Default,,0000,0000,0000,,reattaching that arm back to its original socket.
Dialogue: 0,0:01:30.00,0:01:31.00,Default,,0000,0000,0000,,Now let's zoom out a bit.
Dialogue: 0,0:01:31.00,0:01:32.00,Default,,0000,0000,0000,,Now let's say that you've got
Dialogue: 0,0:01:32.00,0:01:34.00,Default,,0000,0000,0000,,a thousand people on the street,
Dialogue: 0,0:01:34.00,0:01:35.00,Default,,0000,0000,0000,,and all of them start with their limbs
Dialogue: 0,0:01:35.00,0:01:37.00,Default,,0000,0000,0000,,normally attached.
Dialogue: 0,0:01:37.00,0:01:39.00,Default,,0000,0000,0000,,At the beginning, every collision is a chance
Dialogue: 0,0:01:39.00,0:01:43.00,Default,,0000,0000,0000,,for Person A to transfer an arm to Person B's face.
Dialogue: 0,0:01:43.00,0:01:44.00,Default,,0000,0000,0000,,And so at the beginning,
Dialogue: 0,0:01:44.00,0:01:45.00,Default,,0000,0000,0000,,more and more people end up
Dialogue: 0,0:01:45.00,0:01:48.00,Default,,0000,0000,0000,,with arms attached to their faces or arms missing.
Dialogue: 0,0:01:48.00,0:01:51.00,Default,,0000,0000,0000,,But as the number of people with arm-faces
Dialogue: 0,0:01:51.00,0:01:53.00,Default,,0000,0000,0000,,and missing arms grows,
Dialogue: 0,0:01:53.00,0:01:56.00,Default,,0000,0000,0000,,collisions between those people become more likely.
Dialogue: 0,0:01:56.00,0:01:58.00,Default,,0000,0000,0000,,And when they bump into each other,
Dialogue: 0,0:01:58.00,0:01:59.00,Default,,0000,0000,0000,,guess what?
Dialogue: 0,0:01:59.00,0:02:02.00,Default,,0000,0000,0000,,Normal-appendage people are reproduced.
Dialogue: 0,0:02:02.00,0:02:05.00,Default,,0000,0000,0000,,Now the number of limb transfers per second forward
Dialogue: 0,0:02:05.00,0:02:07.00,Default,,0000,0000,0000,,will start high and then fall,
Dialogue: 0,0:02:07.00,0:02:10.00,Default,,0000,0000,0000,,and the number of limb transfers per second backward
Dialogue: 0,0:02:10.00,0:02:12.00,Default,,0000,0000,0000,,will start at zero and then rise.
Dialogue: 0,0:02:12.00,0:02:13.00,Default,,0000,0000,0000,,Eventually they'll meet,
Dialogue: 0,0:02:13.00,0:02:14.00,Default,,0000,0000,0000,,they'll be the same.
Dialogue: 0,0:02:14.00,0:02:15.00,Default,,0000,0000,0000,,And when that happens,
Dialogue: 0,0:02:15.00,0:02:19.00,Default,,0000,0000,0000,,the number of people in each state stops changing,
Dialogue: 0,0:02:19.00,0:02:21.00,Default,,0000,0000,0000,,even though people are still bumping into each other
Dialogue: 0,0:02:21.00,0:02:23.00,Default,,0000,0000,0000,,and exchanging limbs.
Dialogue: 0,0:02:23.00,0:02:25.00,Default,,0000,0000,0000,,Now how many people do you think
Dialogue: 0,0:02:25.00,0:02:26.00,Default,,0000,0000,0000,,there are in each state?
Dialogue: 0,0:02:26.00,0:02:27.00,Default,,0000,0000,0000,,Half and half, right?
Dialogue: 0,0:02:27.00,0:02:29.00,Default,,0000,0000,0000,,No, well, maybe.
Dialogue: 0,0:02:29.00,0:02:30.00,Default,,0000,0000,0000,,It depends.
Dialogue: 0,0:02:30.00,0:02:32.00,Default,,0000,0000,0000,,It could be 50/50,
Dialogue: 0,0:02:32.00,0:02:33.00,Default,,0000,0000,0000,,but it could be 60/40
Dialogue: 0,0:02:33.00,0:02:34.00,Default,,0000,0000,0000,,or 15/85,
Dialogue: 0,0:02:34.00,0:02:35.00,Default,,0000,0000,0000,,or anything.
Dialogue: 0,0:02:35.00,0:02:38.00,Default,,0000,0000,0000,,We chemists have to get our little, gloved hands dirty
Dialogue: 0,0:02:38.00,0:02:41.00,Default,,0000,0000,0000,,- ah, well, we're in a lab so not really dirty -
Dialogue: 0,0:02:41.00,0:02:43.00,Default,,0000,0000,0000,,to figure out what the actually distribution
Dialogue: 0,0:02:43.00,0:02:44.00,Default,,0000,0000,0000,,of molecules is.
Dialogue: 0,0:02:44.00,0:02:46.00,Default,,0000,0000,0000,,Even though each of limb transfers
Dialogue: 0,0:02:46.00,0:02:49.00,Default,,0000,0000,0000,,is a pretty dramatic event for the people involved,
Dialogue: 0,0:02:49.00,0:02:50.00,Default,,0000,0000,0000,,if we zoom out,
Dialogue: 0,0:02:50.00,0:02:53.00,Default,,0000,0000,0000,,we see population numbers that don't change.
Dialogue: 0,0:02:53.00,0:02:55.00,Default,,0000,0000,0000,,We can this nirvana equilibrium,
Dialogue: 0,0:02:55.00,0:02:58.00,Default,,0000,0000,0000,,and it doesn't just happen with chemical reactions.
Dialogue: 0,0:02:58.00,0:02:59.00,Default,,0000,0000,0000,,Things like gene pools
Dialogue: 0,0:02:59.00,0:03:02.00,Default,,0000,0000,0000,,and highway traffic show the same pattern.
Dialogue: 0,0:03:02.00,0:03:04.00,Default,,0000,0000,0000,,It looks pretty still from 30,000 feet,
Dialogue: 0,0:03:04.00,0:03:06.00,Default,,0000,0000,0000,,but there is lots of crazy stuff
Dialogue: 0,0:03:06.00,0:03:07.00,Default,,0000,0000,0000,,happening on the ground,
Dialogue: 0,0:03:07.00,0:03:10.00,Default,,0000,0000,0000,,you just need to zoom in to see it.