[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.61,0:00:08.67,Default,,0000,0000,0000,,Water is the liquid of life.
Dialogue: 0,0:00:08.67,0:00:09.39,Default,,0000,0000,0000,,We drink it,
Dialogue: 0,0:00:09.39,0:00:10.24,Default,,0000,0000,0000,,we bathe in it,
Dialogue: 0,0:00:10.24,0:00:10.86,Default,,0000,0000,0000,,we farm,
Dialogue: 0,0:00:10.86,0:00:11.20,Default,,0000,0000,0000,,cook,
Dialogue: 0,0:00:11.20,0:00:12.30,Default,,0000,0000,0000,,and clean with it.
Dialogue: 0,0:00:12.30,0:00:14.75,Default,,0000,0000,0000,,It's the most abundant molecule in our bodies.
Dialogue: 0,0:00:14.75,0:00:16.53,Default,,0000,0000,0000,,In fact, every life form we know of
Dialogue: 0,0:00:16.53,0:00:18.28,Default,,0000,0000,0000,,would die without it.
Dialogue: 0,0:00:18.28,0:00:20.38,Default,,0000,0000,0000,,But most importantly, without water,
Dialogue: 0,0:00:20.38,0:00:22.48,Default,,0000,0000,0000,,we wouldn't have
Dialogue: 0,0:00:22.48,0:00:23.43,Default,,0000,0000,0000,,iced tea.
Dialogue: 0,0:00:23.43,0:00:26.07,Default,,0000,0000,0000,,Mmmm, iced tea.
Dialogue: 0,0:00:27.75,0:00:29.87,Default,,0000,0000,0000,,Why do these ice cubes float?
Dialogue: 0,0:00:29.87,0:00:31.92,Default,,0000,0000,0000,,If these were cubes of solid argon
Dialogue: 0,0:00:31.92,0:00:33.82,Default,,0000,0000,0000,,in a cup of liquid argon,
Dialogue: 0,0:00:33.82,0:00:34.98,Default,,0000,0000,0000,,they would sink.
Dialogue: 0,0:00:34.98,0:00:37.64,Default,,0000,0000,0000,,And the same goes for most other substances.
Dialogue: 0,0:00:37.64,0:00:40.48,Default,,0000,0000,0000,,But solid water, a.k.a. ice,
Dialogue: 0,0:00:40.48,0:00:43.39,Default,,0000,0000,0000,,is somehow less dense than liquid water.
Dialogue: 0,0:00:43.39,0:00:45.22,Default,,0000,0000,0000,,How's that possible?
Dialogue: 0,0:00:45.22,0:00:46.93,Default,,0000,0000,0000,,You already know that every water molecule
Dialogue: 0,0:00:46.93,0:00:48.97,Default,,0000,0000,0000,,is made up of two hydrogen atoms
Dialogue: 0,0:00:48.97,0:00:51.31,Default,,0000,0000,0000,,bonded to one oxygen atom.
Dialogue: 0,0:00:51.31,0:00:52.68,Default,,0000,0000,0000,,Let's look at a few of the molecules
Dialogue: 0,0:00:52.68,0:00:54.17,Default,,0000,0000,0000,,in a drop of water,
Dialogue: 0,0:00:54.17,0:00:57.77,Default,,0000,0000,0000,,and let's say the temperature is 25 degrees Celcius.
Dialogue: 0,0:00:57.77,0:00:59.37,Default,,0000,0000,0000,,The molecules are bending,
Dialogue: 0,0:00:59.37,0:01:00.08,Default,,0000,0000,0000,,stretching,
Dialogue: 0,0:01:00.08,0:01:00.70,Default,,0000,0000,0000,,spinning,
Dialogue: 0,0:01:00.70,0:01:02.54,Default,,0000,0000,0000,,and moving through space.
Dialogue: 0,0:01:02.54,0:01:04.74,Default,,0000,0000,0000,,Now, let's lower the temperature,
Dialogue: 0,0:01:04.74,0:01:06.61,Default,,0000,0000,0000,,which will reduce the amount of kinetic energy
Dialogue: 0,0:01:06.61,0:01:08.78,Default,,0000,0000,0000,,each of these molecules has
Dialogue: 0,0:01:08.78,0:01:11.66,Default,,0000,0000,0000,,so they'll bend, stretch, spin, and move less.
Dialogue: 0,0:01:11.66,0:01:13.30,Default,,0000,0000,0000,,And that means that on average,
Dialogue: 0,0:01:13.30,0:01:15.46,Default,,0000,0000,0000,,they'll take up less space.
Dialogue: 0,0:01:15.46,0:01:17.09,Default,,0000,0000,0000,,Now, you'd think that as the liquid water
Dialogue: 0,0:01:17.09,0:01:18.53,Default,,0000,0000,0000,,starts to freeze,
Dialogue: 0,0:01:18.53,0:01:20.14,Default,,0000,0000,0000,,the molecules would just pack together
Dialogue: 0,0:01:20.14,0:01:21.73,Default,,0000,0000,0000,,more and more closely,
Dialogue: 0,0:01:21.73,0:01:23.74,Default,,0000,0000,0000,,but that's not what happens.
Dialogue: 0,0:01:23.74,0:01:25.09,Default,,0000,0000,0000,,Water has a special kind
Dialogue: 0,0:01:25.09,0:01:26.60,Default,,0000,0000,0000,,of interaction between molecules
Dialogue: 0,0:01:26.60,0:01:29.10,Default,,0000,0000,0000,,that most other substances don't have,
Dialogue: 0,0:01:29.10,0:01:30.98,Default,,0000,0000,0000,,and it's called a hydrogen bond.
Dialogue: 0,0:01:30.98,0:01:32.93,Default,,0000,0000,0000,,Now, remember that in a covalent bond
Dialogue: 0,0:01:32.93,0:01:35.19,Default,,0000,0000,0000,,two electrons are shared,
Dialogue: 0,0:01:35.19,0:01:36.40,Default,,0000,0000,0000,,usually unequally,
Dialogue: 0,0:01:36.40,0:01:37.61,Default,,0000,0000,0000,,between atoms.
Dialogue: 0,0:01:37.61,0:01:38.78,Default,,0000,0000,0000,,In a hydrogen bond,
Dialogue: 0,0:01:38.78,0:01:41.77,Default,,0000,0000,0000,,a hydrogen atom is shared, also unequally,
Dialogue: 0,0:01:41.77,0:01:43.39,Default,,0000,0000,0000,,between atoms.
Dialogue: 0,0:01:43.39,0:01:46.12,Default,,0000,0000,0000,,One hydrogen bond looks like this.
Dialogue: 0,0:01:46.12,0:01:47.88,Default,,0000,0000,0000,,Two look like this.
Dialogue: 0,0:01:47.88,0:01:48.78,Default,,0000,0000,0000,,Here's three
Dialogue: 0,0:01:48.78,0:01:49.72,Default,,0000,0000,0000,,and four
Dialogue: 0,0:01:49.72,0:01:50.72,Default,,0000,0000,0000,,and five,
Dialogue: 0,0:01:50.72,0:01:51.42,Default,,0000,0000,0000,,six,
Dialogue: 0,0:01:51.42,0:01:51.96,Default,,0000,0000,0000,,seven,
Dialogue: 0,0:01:51.96,0:01:52.44,Default,,0000,0000,0000,,eight,
Dialogue: 0,0:01:52.44,0:01:52.92,Default,,0000,0000,0000,,nine,
Dialogue: 0,0:01:52.92,0:01:53.23,Default,,0000,0000,0000,,ten,
Dialogue: 0,0:01:53.23,0:01:53.55,Default,,0000,0000,0000,,eleven,
Dialogue: 0,0:01:53.55,0:01:54.31,Default,,0000,0000,0000,,twelve,
Dialogue: 0,0:01:54.31,0:01:56.39,Default,,0000,0000,0000,,I could go on.
Dialogue: 0,0:01:56.39,0:01:57.78,Default,,0000,0000,0000,,In a single drop of water,
Dialogue: 0,0:01:57.78,0:02:00.15,Default,,0000,0000,0000,,hydrogen bonds form extended networks
Dialogue: 0,0:02:00.15,0:02:02.03,Default,,0000,0000,0000,,between hundreds, thousands, millions,
Dialogue: 0,0:02:02.03,0:02:04.20,Default,,0000,0000,0000,,billions, trillions of molecules,
Dialogue: 0,0:02:04.20,0:02:07.61,Default,,0000,0000,0000,,and these bonds are constantly breaking and reforming.
Dialogue: 0,0:02:07.61,0:02:09.82,Default,,0000,0000,0000,,Now, back to our water as it cools down.
Dialogue: 0,0:02:09.82,0:02:11.87,Default,,0000,0000,0000,,Above 4 degrees Celcius,
Dialogue: 0,0:02:11.87,0:02:13.52,Default,,0000,0000,0000,,the kinetic energy of the water molecules
Dialogue: 0,0:02:13.52,0:02:16.53,Default,,0000,0000,0000,,keeps their interactions with each other short.
Dialogue: 0,0:02:16.53,0:02:18.45,Default,,0000,0000,0000,,Hydrogen bonds form and break
Dialogue: 0,0:02:18.45,0:02:20.28,Default,,0000,0000,0000,,like high school relationships,
Dialogue: 0,0:02:20.28,0:02:22.59,Default,,0000,0000,0000,,that is to say, quickly.
Dialogue: 0,0:02:22.59,0:02:23.78,Default,,0000,0000,0000,,But below 4 degrees,
Dialogue: 0,0:02:23.78,0:02:25.71,Default,,0000,0000,0000,,the kinetic energy of the water molecules
Dialogue: 0,0:02:25.71,0:02:27.78,Default,,0000,0000,0000,,starts to fall below the energy
Dialogue: 0,0:02:27.78,0:02:29.67,Default,,0000,0000,0000,,of the hydrogen bonds.
Dialogue: 0,0:02:29.67,0:02:32.30,Default,,0000,0000,0000,,So, hydrogen bonds form much more frequently
Dialogue: 0,0:02:32.30,0:02:33.63,Default,,0000,0000,0000,,than they break
Dialogue: 0,0:02:33.63,0:02:35.48,Default,,0000,0000,0000,,and beautiful structures start to emerge
Dialogue: 0,0:02:35.48,0:02:37.11,Default,,0000,0000,0000,,from the chaos.
Dialogue: 0,0:02:37.11,0:02:39.45,Default,,0000,0000,0000,,This is what solid water, ice,
Dialogue: 0,0:02:39.45,0:02:41.95,Default,,0000,0000,0000,,looks like on the molecular level.
Dialogue: 0,0:02:41.95,0:02:44.30,Default,,0000,0000,0000,,Notice that the ordered, hexagonal structure
Dialogue: 0,0:02:44.30,0:02:47.00,Default,,0000,0000,0000,,is less dense than the disordered structure
Dialogue: 0,0:02:47.00,0:02:48.74,Default,,0000,0000,0000,,of liquid water.
Dialogue: 0,0:02:48.74,0:02:50.94,Default,,0000,0000,0000,,And you know that if an object is less dense
Dialogue: 0,0:02:50.94,0:02:52.37,Default,,0000,0000,0000,,than the fluid it's in,
Dialogue: 0,0:02:52.37,0:02:53.65,Default,,0000,0000,0000,,it will float.
Dialogue: 0,0:02:53.65,0:02:55.53,Default,,0000,0000,0000,,So, ice floats on water,
Dialogue: 0,0:02:55.53,0:02:56.73,Default,,0000,0000,0000,,so what?
Dialogue: 0,0:02:56.73,0:02:59.64,Default,,0000,0000,0000,,Well, let's consider a world without floating ice.
Dialogue: 0,0:02:59.64,0:03:00.100,Default,,0000,0000,0000,,The coldest part of the ocean
Dialogue: 0,0:03:00.100,0:03:03.24,Default,,0000,0000,0000,,would be the pitch-black ocean floor,
Dialogue: 0,0:03:03.24,0:03:05.16,Default,,0000,0000,0000,,once frozen, always frozen.
Dialogue: 0,0:03:05.16,0:03:06.57,Default,,0000,0000,0000,,Forget lobster rolls
Dialogue: 0,0:03:06.57,0:03:08.49,Default,,0000,0000,0000,,since crustaceans would lose their habitats,
Dialogue: 0,0:03:08.49,0:03:11.14,Default,,0000,0000,0000,,or sushi since kelp forests wouldn't grow.
Dialogue: 0,0:03:11.14,0:03:13.26,Default,,0000,0000,0000,,What would Canadian kids do in winter
Dialogue: 0,0:03:13.26,0:03:15.35,Default,,0000,0000,0000,,without pond hockey or ice fishing?
Dialogue: 0,0:03:15.35,0:03:17.13,Default,,0000,0000,0000,,And forget James Cameron's Oscar
Dialogue: 0,0:03:17.13,0:03:20.26,Default,,0000,0000,0000,,because the Titanic totally would have made it.
Dialogue: 0,0:03:20.26,0:03:22.09,Default,,0000,0000,0000,,Say goodbye to the white polar ice caps
Dialogue: 0,0:03:22.09,0:03:23.16,Default,,0000,0000,0000,,reflecting sunlight
Dialogue: 0,0:03:23.16,0:03:25.10,Default,,0000,0000,0000,,that would otherwise bake the planet.
Dialogue: 0,0:03:25.10,0:03:27.29,Default,,0000,0000,0000,,In fact, forget the oceans as we know them,
Dialogue: 0,0:03:27.29,0:03:29.69,Default,,0000,0000,0000,,which at over 70% of the Earth's surface area,
Dialogue: 0,0:03:29.69,0:03:32.11,Default,,0000,0000,0000,,regulate the atmosphere of the whole planet.
Dialogue: 0,0:03:32.52,0:03:33.86,Default,,0000,0000,0000,,But worst of all,
Dialogue: 0,0:03:33.86,0:03:37.25,Default,,0000,0000,0000,,there would be no iced tea.
Dialogue: 0,0:03:37.25,0:03:40.38,Default,,0000,0000,0000,,Mmmmm, iced tea.