[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.74,0:00:10.33,Default,,0000,0000,0000,,Why does salt dissolve in water but oil doesn't?
Dialogue: 0,0:00:10.33,0:00:12.12,Default,,0000,0000,0000,,Well, in a word, chemistry,
Dialogue: 0,0:00:12.12,0:00:14.33,Default,,0000,0000,0000,,but that's not very satisfying, is it?
Dialogue: 0,0:00:14.33,0:00:17.44,Default,,0000,0000,0000,,Well, the reason salt dissolves and oil does not
Dialogue: 0,0:00:17.44,0:00:19.15,Default,,0000,0000,0000,,comes down to the two big reasons
Dialogue: 0,0:00:19.15,0:00:21.35,Default,,0000,0000,0000,,why anything happens at all:
Dialogue: 0,0:00:21.35,0:00:22.28,Default,,0000,0000,0000,,energetics
Dialogue: 0,0:00:22.28,0:00:23.49,Default,,0000,0000,0000,,and entropy.
Dialogue: 0,0:00:23.49,0:00:25.32,Default,,0000,0000,0000,,Energetics deals primarily
Dialogue: 0,0:00:25.32,0:00:28.20,Default,,0000,0000,0000,,with the attractive forces between things.
Dialogue: 0,0:00:28.20,0:00:31.16,Default,,0000,0000,0000,,When we look at oil or salt in water,
Dialogue: 0,0:00:31.16,0:00:34.15,Default,,0000,0000,0000,,we focus on the forces between particles
Dialogue: 0,0:00:34.15,0:00:36.78,Default,,0000,0000,0000,,on a very, very, very small scale,
Dialogue: 0,0:00:36.78,0:00:38.18,Default,,0000,0000,0000,,the molecular level.
Dialogue: 0,0:00:38.18,0:00:39.90,Default,,0000,0000,0000,,To give you a sense of this scale,
Dialogue: 0,0:00:39.90,0:00:41.60,Default,,0000,0000,0000,,in one glass of water,
Dialogue: 0,0:00:41.60,0:00:43.11,Default,,0000,0000,0000,,there are more molecules
Dialogue: 0,0:00:43.11,0:00:45.82,Default,,0000,0000,0000,,than known stars in the universe.
Dialogue: 0,0:00:45.82,0:00:49.45,Default,,0000,0000,0000,,Now, all of these molecules are in constant motion,
Dialogue: 0,0:00:49.45,0:00:52.46,Default,,0000,0000,0000,,moving, vibrating, and rotating.
Dialogue: 0,0:00:52.46,0:00:54.77,Default,,0000,0000,0000,,What prevents almost all of those molecules
Dialogue: 0,0:00:54.77,0:00:56.86,Default,,0000,0000,0000,,from just flying out of the glass
Dialogue: 0,0:00:56.86,0:01:00.03,Default,,0000,0000,0000,,are the attractive interactions between molecules.
Dialogue: 0,0:01:00.03,0:01:01.23,Default,,0000,0000,0000,,The strength of the interactions
Dialogue: 0,0:01:01.23,0:01:04.48,Default,,0000,0000,0000,,between water, itself, and other substances
Dialogue: 0,0:01:04.48,0:01:07.73,Default,,0000,0000,0000,,is what we mean when we say energetics.
Dialogue: 0,0:01:07.73,0:01:09.87,Default,,0000,0000,0000,,You can think of the water molecules engaging
Dialogue: 0,0:01:09.87,0:01:11.42,Default,,0000,0000,0000,,in a constant dance,
Dialogue: 0,0:01:11.42,0:01:13.05,Default,,0000,0000,0000,,sort of like a square dance
Dialogue: 0,0:01:13.05,0:01:16.50,Default,,0000,0000,0000,,where they constantly and randomly exchange partners.
Dialogue: 0,0:01:16.50,0:01:19.18,Default,,0000,0000,0000,,Put simply, the ability for substances
Dialogue: 0,0:01:19.18,0:01:20.68,Default,,0000,0000,0000,,to interact with water,
Dialogue: 0,0:01:20.68,0:01:22.30,Default,,0000,0000,0000,,balanced with how they disrupt
Dialogue: 0,0:01:22.30,0:01:24.88,Default,,0000,0000,0000,,how water interacts with itself,
Dialogue: 0,0:01:24.88,0:01:27.23,Default,,0000,0000,0000,,plays an important role in explaining
Dialogue: 0,0:01:27.23,0:01:29.90,Default,,0000,0000,0000,,why certain things mix well into water
Dialogue: 0,0:01:29.90,0:01:31.65,Default,,0000,0000,0000,,and others don't.
Dialogue: 0,0:01:32.05,0:01:33.91,Default,,0000,0000,0000,,Entropy basically describes
Dialogue: 0,0:01:33.91,0:01:36.63,Default,,0000,0000,0000,,the way things and energy can be arranged
Dialogue: 0,0:01:36.63,0:01:38.50,Default,,0000,0000,0000,,based on random motion.
Dialogue: 0,0:01:38.50,0:01:41.20,Default,,0000,0000,0000,,For example, think of the air in a room.
Dialogue: 0,0:01:41.20,0:01:44.06,Default,,0000,0000,0000,,Imagine all the different possible arrangements
Dialogue: 0,0:01:44.06,0:01:46.65,Default,,0000,0000,0000,,in space for the trillions of particles
Dialogue: 0,0:01:46.65,0:01:48.13,Default,,0000,0000,0000,,that make up the air.
Dialogue: 0,0:01:48.13,0:01:49.17,Default,,0000,0000,0000,,Some of those arrangments
Dialogue: 0,0:01:49.17,0:01:52.16,Default,,0000,0000,0000,,might have all the oxygen molecules over here
Dialogue: 0,0:01:52.16,0:01:54.81,Default,,0000,0000,0000,,and all the nitrogen molecules over there,
Dialogue: 0,0:01:54.81,0:01:55.86,Default,,0000,0000,0000,,separated.
Dialogue: 0,0:01:55.86,0:01:58.02,Default,,0000,0000,0000,,But far more of those possible arrangments
Dialogue: 0,0:01:58.02,0:02:01.02,Default,,0000,0000,0000,,have those molecules mixed up with one another.
Dialogue: 0,0:02:01.02,0:02:03.48,Default,,0000,0000,0000,,So, entropy favors mixing.
Dialogue: 0,0:02:03.48,0:02:06.33,Default,,0000,0000,0000,,Energetics deals with attractive forces.
Dialogue: 0,0:02:06.33,0:02:08.42,Default,,0000,0000,0000,,And so, if attractive forces are present,
Dialogue: 0,0:02:08.42,0:02:10.32,Default,,0000,0000,0000,,the probability of some arrangements
Dialogue: 0,0:02:10.32,0:02:11.50,Default,,0000,0000,0000,,can be enhanced,
Dialogue: 0,0:02:11.50,0:02:13.78,Default,,0000,0000,0000,,the ones where things are attracted to each other.
Dialogue: 0,0:02:13.78,0:02:16.29,Default,,0000,0000,0000,,So, it is always the balance of these two things
Dialogue: 0,0:02:16.29,0:02:18.87,Default,,0000,0000,0000,,that determines what happens.
Dialogue: 0,0:02:18.87,0:02:20.28,Default,,0000,0000,0000,,On the molecular level,
Dialogue: 0,0:02:20.28,0:02:22.66,Default,,0000,0000,0000,,water is comprised of water molecules,
Dialogue: 0,0:02:22.66,0:02:25.83,Default,,0000,0000,0000,,made up of two hydrogen atoms and an oxygen atom.
Dialogue: 0,0:02:25.83,0:02:28.50,Default,,0000,0000,0000,,As liquid water, these molecules are engaged
Dialogue: 0,0:02:28.50,0:02:30.83,Default,,0000,0000,0000,,in a constant and random square dance
Dialogue: 0,0:02:30.83,0:02:34.39,Default,,0000,0000,0000,,that is called the hydrogen-bonding network.
Dialogue: 0,0:02:34.39,0:02:35.77,Default,,0000,0000,0000,,Entropy favors keeping
Dialogue: 0,0:02:35.77,0:02:38.02,Default,,0000,0000,0000,,the square dance going at all times.
Dialogue: 0,0:02:38.02,0:02:39.31,Default,,0000,0000,0000,,There are always more ways
Dialogue: 0,0:02:39.31,0:02:41.14,Default,,0000,0000,0000,,that all the water molecules can arrange
Dialogue: 0,0:02:41.14,0:02:42.35,Default,,0000,0000,0000,,in a square dance,
Dialogue: 0,0:02:42.35,0:02:44.08,Default,,0000,0000,0000,,as compared to if the water molecules
Dialogue: 0,0:02:44.08,0:02:45.42,Default,,0000,0000,0000,,did a line dance.
Dialogue: 0,0:02:45.42,0:02:47.78,Default,,0000,0000,0000,,So, the square dance constantly goes on.
Dialogue: 0,0:02:47.78,0:02:50.75,Default,,0000,0000,0000,,So, what happens when you put salt in the water?
Dialogue: 0,0:02:50.75,0:02:52.75,Default,,0000,0000,0000,,Well, on the molecular level,
Dialogue: 0,0:02:52.75,0:02:55.58,Default,,0000,0000,0000,,salt is actually made up of two different ions,
Dialogue: 0,0:02:55.58,0:02:57.84,Default,,0000,0000,0000,,chlorine and sodium,
Dialogue: 0,0:02:57.84,0:03:00.08,Default,,0000,0000,0000,,that are organized like a brick wall.
Dialogue: 0,0:03:00.08,0:03:01.50,Default,,0000,0000,0000,,They show up to the dance
Dialogue: 0,0:03:01.50,0:03:03.39,Default,,0000,0000,0000,,as a big group in formation
Dialogue: 0,0:03:03.39,0:03:05.04,Default,,0000,0000,0000,,and sit on the side at first,
Dialogue: 0,0:03:05.04,0:03:07.43,Default,,0000,0000,0000,,shy and a bit reluctant to break apart
Dialogue: 0,0:03:07.43,0:03:10.27,Default,,0000,0000,0000,,into individual ions to join the dance.
Dialogue: 0,0:03:10.27,0:03:12.46,Default,,0000,0000,0000,,But secretly, those shy dancers
Dialogue: 0,0:03:12.46,0:03:15.01,Default,,0000,0000,0000,,just want someone to ask them to join.
Dialogue: 0,0:03:15.01,0:03:18.23,Default,,0000,0000,0000,,So, when a water randomly bumps into one of them
Dialogue: 0,0:03:18.23,0:03:20.82,Default,,0000,0000,0000,,and pulls them into the dance away from their group,
Dialogue: 0,0:03:20.82,0:03:21.98,Default,,0000,0000,0000,,they go.
Dialogue: 0,0:03:21.98,0:03:23.36,Default,,0000,0000,0000,,And once they go into the dance,
Dialogue: 0,0:03:23.36,0:03:24.95,Default,,0000,0000,0000,,they don't come back out.
Dialogue: 0,0:03:24.95,0:03:27.35,Default,,0000,0000,0000,,And in fact, the addition of the salt ions
Dialogue: 0,0:03:27.35,0:03:29.41,Default,,0000,0000,0000,,adds more possible dance positions
Dialogue: 0,0:03:29.41,0:03:30.79,Default,,0000,0000,0000,,in the square dance,
Dialogue: 0,0:03:30.79,0:03:33.97,Default,,0000,0000,0000,,so it is favored for them to stay dancing with water.
Dialogue: 0,0:03:35.16,0:03:37.12,Default,,0000,0000,0000,,Now, let's take oil.
Dialogue: 0,0:03:37.12,0:03:39.80,Default,,0000,0000,0000,,With oil, the molecules are sort of interested
Dialogue: 0,0:03:39.80,0:03:40.89,Default,,0000,0000,0000,,in dancing with water,
Dialogue: 0,0:03:40.89,0:03:43.14,Default,,0000,0000,0000,,so entropy favors them joining the dance.
Dialogue: 0,0:03:43.14,0:03:45.19,Default,,0000,0000,0000,,The problem is that oil molecules
Dialogue: 0,0:03:45.19,0:03:47.47,Default,,0000,0000,0000,,are wearing gigantic ballgowns,
Dialogue: 0,0:03:47.47,0:03:50.04,Default,,0000,0000,0000,,and they're way bigger than water molecules.
Dialogue: 0,0:03:50.04,0:03:52.47,Default,,0000,0000,0000,,So, when an oil molecule gets pulled in,
Dialogue: 0,0:03:52.47,0:03:55.30,Default,,0000,0000,0000,,their size is really disruptive to the dance
Dialogue: 0,0:03:55.30,0:03:56.92,Default,,0000,0000,0000,,and the random exchange of partners
Dialogue: 0,0:03:56.92,0:03:58.62,Default,,0000,0000,0000,,that the waters engage in,
Dialogue: 0,0:03:58.62,0:04:00.33,Default,,0000,0000,0000,,a very important part of the dance.
Dialogue: 0,0:04:00.33,0:04:02.88,Default,,0000,0000,0000,,In addition, they are not great dancers.
Dialogue: 0,0:04:02.88,0:04:04.80,Default,,0000,0000,0000,,The water molecules try to engage
Dialogue: 0,0:04:04.80,0:04:06.46,Default,,0000,0000,0000,,the oil molecules in the dance,
Dialogue: 0,0:04:06.46,0:04:08.89,Default,,0000,0000,0000,,but they just keep bumping into their dresses
Dialogue: 0,0:04:08.89,0:04:11.06,Default,,0000,0000,0000,,and taking up all the room on the dance floor.
Dialogue: 0,0:04:11.06,0:04:13.72,Default,,0000,0000,0000,,There are way more ways the waters can dance
Dialogue: 0,0:04:13.72,0:04:15.76,Default,,0000,0000,0000,,when the oil gets off the floor,
Dialogue: 0,0:04:15.76,0:04:18.21,Default,,0000,0000,0000,,so the waters squeeze out the oil,
Dialogue: 0,0:04:18.21,0:04:20.80,Default,,0000,0000,0000,,pushing it back to the bench with the others.
Dialogue: 0,0:04:20.80,0:04:22.89,Default,,0000,0000,0000,,Pretty soon, when a large number of oils
Dialogue: 0,0:04:22.89,0:04:24.97,Default,,0000,0000,0000,,have been squeezed over to the side,
Dialogue: 0,0:04:24.97,0:04:27.03,Default,,0000,0000,0000,,they band together to commiserate
Dialogue: 0,0:04:27.03,0:04:29.46,Default,,0000,0000,0000,,about how unfair the waters are being
Dialogue: 0,0:04:29.46,0:04:31.41,Default,,0000,0000,0000,,and stick together as a group.
Dialogue: 0,0:04:31.41,0:04:32.75,Default,,0000,0000,0000,,So, it is this combination
Dialogue: 0,0:04:32.75,0:04:35.08,Default,,0000,0000,0000,,of the interactions between molecules
Dialogue: 0,0:04:35.08,0:04:37.47,Default,,0000,0000,0000,,and the configurations available to them
Dialogue: 0,0:04:37.47,0:04:38.89,Default,,0000,0000,0000,,when they're moving randomly
Dialogue: 0,0:04:38.89,0:04:41.22,Default,,0000,0000,0000,,that dictates whether they mix.
Dialogue: 0,0:04:41.22,0:04:43.64,Default,,0000,0000,0000,,In other words, water and oil don't mix
Dialogue: 0,0:04:43.64,0:04:47.22,Default,,0000,0000,0000,,because they just don't make great dance partners.