Water - Liquid Awesome: Crash Course Biology #2

Hank teaches us why water is one of the most fascinating and important substances in the universe.

Review:
Re-watch = 00:00
Introduction = 00:42
Molecular structure & hydrogen bonds = 01:38
Cohesion & surface tension = 02:46
Adhesion = 03:31
Hydrophilic substances = 04:42
Hydrophobic substances = 05:14
Henry Cavendish = 05:49
Ice Density = 07:45
Heat Capacity = 09:10

Citations:

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[amberembers]

A summary!

Video Two: Water
 H2O uses a covalent bond: each hydrogen shares an electron with oxygen. It is thus a polar molecule.
 All water molecules are attracted to each other due to this polarity – these are hydrogen bonds (between the positive and negative poles of different molecules)
 Hydrogen bonds in water results in high cohesion, and thus high surface tension.
 Cohesion is the attraction between two like things (e.g. two water molecules).
 Water has the highest cohesion of any non-metallic liquid.
 Adhesion is the attraction between two unlike things (e.g. water and glass).
 Capillary action is water defying gravity.
 Water is the greatest solvents (due to its polarity).
 Hydrophilic molecules are polar – their polarity is stronger than the cohesive forces of water.
 Hydrophobic molecules cannot break the cohesive forces of water because they are non-polar.
 Solid water is less dense than liquid water due to hydrogen bonds forming crystalline structures that space molecules apart more easily (when frozen).
 Water has a very high heat capacity – it is good at holding on to heat, thus oceans regulate climate and temperature of planets.

[nikeraelynn]

to summarize this video :
H2O is a covalent bond
hydrogen bonds stick together
hydrogen bonds are weak
cohesion is the attraction between two like things
water has the highest cohesion of any non-metallic liquid
adhesion is the act of water spreading out
adhesion is the attraction between two unlike things
capillary action is water defying gravity
water is a polar molecule
water is a solvent (the greatest)

[guillaumeesce]

"So around 32 degrees Fahrenheit... or 0 degree Celsius if you're a scientist or from a part of the world where things make sense" I'm dying here

[damnage]

"It can't penetrate and come into it" Hank likes his biology hardcore.

[Victr]

I'm an accounting student, but I had a horrible chemistry teacher in high school and I'm taking this courses solely to have a better understanding of the world around me, and all I wanted to say was that they've been really helpful in making me understand (with a little extra reasearch) all the basics of chemistry! Thank you crashcourse!

[RyGuyMemes]

"It can't penetrate and come into it :) " I like how he has a huge smirk on his face when he said that pun.

[ptrocks]

"It can't penetrate and come into it"-Hank

[coffeeandtear]

"This is what causes some bugs, I think one lizard, and also one Jesus to be able to walk on water." Hank how the hell were you able to say that with a straight face? 😂😂😂😂

[rodolfobeguiristain]

Wow there used to be allot more sex jokes in the old crashcourse lol

[GideonGleeful]

I think we all know why Hank smiled when he said "it can't penetrate and come into it."

[bishamontenrozy]

"allows some bugs, one lizard, and also one jesus to walk on water" XD
savage af

[KalvinGarrah]

"XD you're gonna do so good on that test you either do or don't have coming up"
for me that's the bio midterm tommorow

[heavybrettal]

I gotta say how amazing this channel is. I hate sitting at my desk and listening to my professor's "simplified" lectures and instead I usually watch YouTube videos with an unusually high amount of jump cuts. However, it is because of these jump cuts and how fast paced the teaching process is, is how I can enjoy learning about Biology WAY more than with my other lectures.

[ryan.sullivan]

hank i hope you know that you are being taught in my class

[chadwilliams]

i was going to show this to my class....then 5:22

[withitgoesasmile]

Do you know what makes these videos so useful, fun and interesting? It's the fact that Hank (and John on the ones he does) really cares about what he's talking about, which means he actually WANTS to teach it to you, as opposed to just has to because it's his job.

[Ureyeuh]

I credit Crash Course with my success in BIO105. When you cover 2 chapters a week and you're taking 15 credit hours/4 classes total, it's pretty much hilariously impossible to actually grasp the material as you progress and REALLY understand it.

[claudekennedy]

OH MY GOD! I WANT TO SAY THANK YOU TO HANK GREEN AND EVERYBODY ELSE WHO HELPS MAKE THIS PRODUCTION!!! IT HELPS ME STUDY SO MUCH!!! (btw im just an average student taking a bio class with the dire need to pass)

[peacefulinvasion]

When the vast majority of people are here because of a test, and you're literally just watching this because they replaced all of your documentaries with reality shows on the discovery channel.

[djuknowme]

My teacher showed us this vid in Bio, and I couldn't hear anything else in the rest of the video over the sound of immature guys laughing about the "penetrates and comes into" line. So, I'm here to watch the rest of the video.