what's up everybody so in this video we're going to be talking about water everything that you need to know about water so let's just get straight into this now when when I ask you where is water what do you think of most people think habitats so they think ah the ocean um my pool the dam the river right most people immediately think of this one um but in fact there are so many other places where you can find water water is everywhere now for example let's think about a person let's think about Elon Musk when we look at Elon Musk we know just like every person he is made up of billions of cells right maybe you don't know what cells is don't worry that's for another day another video but for now a cell is basically the smallest thing we're made of we're made up of billions of these tiny little things these cells um now cells are made up of mostly water that's why we are mostly water maybe you've heard before humans or living things are like 70 water and you'd be like damn how is that even possible how are we 70 water we're 70 water because cell we're made up of cells and cells are 70 water they're mostly water um hence we are mostly water okay but how our cells mostly water like I said you'll learn about cells later but for now we gotta just mention a few things a cell is a little unit like this and it's got a lot of these little factories these Factories do different things and when they all work together the cell survives okay and hence we survive now diesel factories are called organelles each Factory has a different job now organelles contain mostly water okay now what else outside of these factories there's this little light blue color thing here these are called This is called cytoplasm okay and a bunch of reactions and things happen there and guess what it's basically just water now okay so now we know that habitat has water um we are mostly water because our cells are mostly water okay what else in between cells there's just water okay so we got cells in but we got water in between our cells as well and then one last place is this what happens when you get cut with a knife unless you're Superman you're gonna bleed right and blood comes from where it comes from your blood vessels blood guess what is mostly water okay so we also have water inside our blood and our P so our body fluids like our pee our poo our vomit um everywhere so we got blood in many we got water in many many places okay so now that we understand water is everywhere not just the ocean we need to learn a little bit about water itself okay um and you're not gonna if you don't like chemistry you're not going to like this too much but there's a because it's biology you don't need to know much detail so we're just going to cover a tad bit okay you need to know a little bit about the structure of water um but not so much detail because this is not chemistry it's biology but if you do chemistry you'll see much more of this so when you think of water um you maybe have heard of H2O right H2O is what some people like to call water why did they like to call it H2O uh guess why so the reason why is because the water structure looks like this okay we got water is made up of an oxygen and two hydrogens the oxygen binds two hydrogens so one oxygen binds to one hydrogen and then also binds to another hydrogen okay damn this is already crazy what do we call this bond this bond is called a covalent bond okay um this Bond here it's a very very strong bond like it's almost impossible to break this Bond now you don't need to know more about this covalent bond because as a chemistry like chemistry thing like I said so just remember the bond that holds together or the oxygen and the hydrogen is called the covalent bond okay it's a kind of a bond is a kind of Attraction it's like when you hold someone's hand and you hold tightly even if people try and pull you apart you're gonna you're gonna still stick together so it's the same thing here there's this kind of bond this kind of force keeping these two together that we call a covalent bond okay great so that's the basic thing also I didn't draw it in this way for no reason make sure that you keep it in a V shape the oxygen on top or whatever doesn't have to be you can also rotate it it doesn't matter as long as it's in a V shape as long as it's in this kind of shape the oxygen bonded to the two hydrogens in a V shape that's very important but we'll talk about this um very shortly more okay so don't think that this is not important we're going to add some more detail now and trust me you need to know this okay we're just learning the very basics of the water structure now okay great so now we know where water is from where it can where we can find it and we know the basic structure so what happens if we put two water molecules next to each other what happens let's look so um yeah let's look at that first okay here so when we put two nah wait let's actually talk about this so we just said right we just said water is everywhere water is everywhere right so how did water come to Earth on the in the first place right because we know for life to exist that's why when people try and find planets to survive on like Mars and and the moon and whatever they always look for planets that have some water on them because water is necessary for life to exist so how did water come to Earth on the first place so a very long time ago the earth was just a rock of boiling boiling lava it was magma just a rock that is just boiling okay it's just like molten lava then over time so obviously if you put water on this kind of planet will it stay there no way it instantly evaporates right so over time over a long period of time cooling happened so cooling right so the earth started getting slowly over many many years getting colder and colder because the lava started getting less and less and after a very long time the Earth was cool enough to retain water so it got to a point where you could put water on the earth um and it would stay there okay so after a very long time this is very simplified obviously because you don't need to know that many details but after a long time of cooling the Earth manage to keep some water now water is important because it keeps it is necessary for life so because water managed to exist cells manage to exist because cells manage to exist we managed to exist because organisms are all made up of cells so that's the basic idea you need to know now now let's go back to the structure of water so remember water is the structure we got an oxygen bonded to two hydrogens so now I want to go even more detail you need to know this though so here we have a cool diagram which I think explains it well we got here an oxygen binding to a hydrogen so this is the hydrogen pulling and this is the oxygen pulling okay they're trying to pull and you'll explain well I'll explain what this means so right here we're only having one oxygen bonded to a hydrogen even though the real structure has oxygen to hydrogen and oxygen to hydrogen because if you understand one of these interactions the other one is exactly the same so let's just look at one so what happens is um I'm going to simplify this because in chemistry you you learned the real more detailed um stuff so I'm going to give you a nice example to help you remember this but basically what happens is in between oxygen and hydrogen there's electrons okay electrons electrons are very negatively charged molecules they're very negative okay so you can have positive molecules and negative molecules and negative things electrons are negative now basically oxygen and hydrogen both like these electrons they want them they want these this negativity in their life it's like they're not happy I mean they're they're too happy they want some negative negativity so they pull on this electrons but just like humans like you're friendly you or your friend is stronger you're not both the exact same strength right so just like this oxygen is pretty strong we can give it a number 3.44 let's say and then we can give hydrogen a strength number of 2.20 you don't need to remember these numbers it's just to get this concept out of the way um so guess what happens if oxygen is stronger than hydrogen which one is going to have more electrons oxygen right it may not have all of them but it's going to have more so the electrons will lean more towards oxygen it is stronger at attracting these electrons so what will that mean that will mean oxygen is going to be what more or less um which one will be more negative oxygen or hydrogen oxygen because oxygen is pulling more of these negative charges towards it meaning we can classify oxygen as more negative so because it's not completely negative it's not going to take all of the electrons it's only going to take slightly more than hydrogen because of this it's not completely negative it is only slightly negative so we're going to call it Delta negative this is just a way of saying it is slightly negative slight negative not completely now on the contrary hydrogen is pulling on electrons and it's getting some but not as much as oxygen so we're going to call it slightly positive because it loses I like more electrons than it's gaining so we call it when you lose negative things you are yourself more positive right um so it's going to be it makes sense because like think about life if you lose negativity in your life some negative person you're going to be more positive okay so it's the same thing here now now next so that's how this one attraction looks like so if we have then a water molecule we have one here the oxygen is therefore negatively charged because they're pulling on these electrons better they're negatively charged the hydrogens will be positively charged so when you put two water molecules next to each other we know from uh from school that positive and negative charges attract so a positive charge will attract this negative charge right it's like magnets so when you put these water molecules together they will attract the positive hydrogen will attract this negative oxygen okay so what do we call this kind of Attraction this kind of bond because it's basically a bond we know this one here was called the covalent bond now the covalent bond was very strong this one here is relatively weak and temporary so when it when a bond is temporary we call it an ephemeral attraction ephemeral just means temporary so it's not going to be there permanently it will form and break and form and break so think about like water flowing when water flows in the ocean these bonds are forming and breaking so that because if they were stuck like this water would be solid right but because they are relatively weak they can break and form and that can cause water to flow right so it's an ephemeral attraction it's a temporary ephemeral just basically means temporary so it forms and goes and forms and goes so let's put another one another water molecule here what's going to happen here of course this negative oxygen will attract to this positive hydrogen now remember how I said this Bond here is the covalent bond this one here is a hydrogen bond so these are the two bonds you're going to need to know about the two bonds now I always find it like very in the beginning I find it very difficult to remember which one is not covalent bond and which one was a hydrogen bond like I always found it so tricky so I found a nice way that can help you out a little bit if you are there in the test and getting a brain fart basically the hydrogen bond remember I said it's the weaker one it's the ephemeral attraction okay it's the weaker Bond it is I like to remember it as hydrogen bonds are hiding they are that's why I made a striped line like um dashed line because they're not as strong they're hiding these Bonds are there but they're also not there like they're not as strong so hydrogen bonds are hiding they are weaker than the covalent bonds okay so that's how you remember it if you don't remember if this one was the hydrogen or covalent bond just remember the hydrogen bonds are hiding so they're the ones in between the water molecules okay now another key word you need to know is polar this will be easy if you do chemistry but if you're a bio student then let's try and get this down um what does polar mean so if you're a polar person you're known to be very emotional one second you're positive one second you're negative one second you're happy and then you're Moody so same thing here this is polar so one side is negative and one side is positive so this is a polar molecule so a polar model molecule is just one that has one side positive and one side negative okay so it's polar a non-polar molecule would just be one that doesn't have a clear positive side and doesn't have a clear negative side okay it's nonpolar now let's try and make this more realistic here let's put a glass of water okay glass of water so when you see a glass of water and you zoom in very very far with a microscope or something so maybe an electron microscope whatever something I can zoom really far you will see these molecules and you'll see these attractions what do we call these attractions again hydrogen bonds right hydrogen bonds now you can imagine these are little bonds so if you put something here unless they break this Bond they will float on the water right so that's kind of interesting here so some small organisms can kind of walk on water if they are light enough because they they won't break these bonds so they won't fall they won't sink into the water okay that's what we'll talk more about this later so overall what do we know now we know now um water is everywhere it's everywhere right nature everywhere we know the structure we know why water came to Earth okay and now we know a little bit about the structure of water you need to know how to draw this and you'll see later there's an IB question that asks you to draw this okay if you can draw this you got it we'll look at it at the end of the video okay so that's what we know now I just mentioned there's a the water is polar right water is polar so I want to give you an example example of a nonpolar molecule uh you don't need to know this I'm just showing it for clear for clarity just to understand so if we use the same concept we assign this molecule it's got carbon and four hydrogens each carbon is bound to four hydrogens then we can say this um by the way carbon always binds to four hydrogens okay but we'll learn about this later um so carbon I mean carbon always has four bonds okay but don't worry about this now so if we assign it again they battle for these electrons and we assign them numbers but notice how carbon and hydrogen has very similar strengths okay they train together they're they train at the same gym okay so they got the same strengths so what happens is the electrons kind of stay in the middle so carbon and hydrogen they both stay neutral so this is a non-polar molecule there is no charges okay it's all neutral so this is a non-polar molecule which means if you put them next to each other they don't have such a strong bond to each other let me show you so if we put two of these molecules next to each other because there's no charges they don't form this kind of hydrogen bond okay they don't form this bond that this doesn't happen so they don't stick they're they're basically easier to be gases because they have no interaction with each other nothing keeping them together so strongly so they are more likely to be gases okay okay so if you understand all this this is the the very important key things you need to understand we're now going to talk about some things about water okay some properties so water has adhesion properties it has cohesion properties it has solvent properties and it has physical properties this sounds like a lot but trust me if you understood well what was going on so far in this video this should be fairly simple and easy to understand but you need to know these things okay let's get into them so cohesion and adhesion in simple terms break down the word Co means each other and adhesion means sticking basically so if you think about it cooperation that means working together right the word Co is there it means each other so cohesion means sticking to each other so cohesion is when water molecules stick to each other so when we looked at this when we looked at the cup this was cohesion the water molecules are sticking to each other this property of water is called cohesion now why is cohesion important okay cohesion is useful for many ways firstly I already mentioned it allows certain organisms to be able to live on water okay because this water these interactions need to be broken before this organism can fall in and if they're light enough they won't break these bonds so that's important okay so here's the official definition it's just when molecules of the same type attract each other so regarding water it's when water molecules attract to each other and the remember let me quiz you again while we're at it what do we call these bonds hydrogen bonds okay good okay let's look at this so um here's the same it's just another picture of the same concept it's this lizard running on water and it's because of surface tension so this let me bring this back when these bonds happen it creates this tension it creates this force that doesn't allow something to quickly step through it okay there's they first have to break the spawn this is called surface tension so water has pretty good surface tension pretty high surface tension which allows some organisms to like live on it now another cool example is this one you can try this when you have a coin and you drip drop by drop how many drops do you think you can put it'll surprise you because because of cohesion it forms this Dome shape normally you would expect this Dome to the water to just fall off the coin when it gets too much but the water sticks together right cohesion they stick together so they end up forming the stone shape instead of falling off because they have this water has an attraction to itself so this Dome shape ends up forming you can try it this is cohesion now let's go to adhesion so adhesion is the opposite it's when molecules attract to other molecules so adhesion would be when water attracts to another kind of molecule so let's say here we have water here's another molecule that's adhesion there's hydrogen bonding of water to another molecule that's adhesion so if we look at this example here of a leaf and a water molecule a water drop I mean this water drop obviously has many many water molecules in it because of this adhesion the water sticks and it doesn't fall off so easily this is called adhesion so this here cohesion adhesion add means to something else co-means to itself okay so cohesion and adhesion means ticking so sticking to itself sticking to other things now why why is there an example of where both of these are used together let's see so we're going to use the example of plants okay so this is soil here this is a plant and it's roots and we know plants take up water through the roots right and the specific pipe that does that is called the xylem but you don't need to worry about this now just know there's a pipe that brings up water right because when plants need water and nutrients to feed the leaves and the fruits and all that right so because they don't have a mouth to drink water so they need to bring water somehow now the method with which they bring up water is called capillary action okay and capillary action uses adhesion and cohesion properties of water let me show you how it works we're going to just briefly run over this okay let's open this big brain box so here we got some straws and we got a pool when you stick a straw into the pool and you suck water out of it how does it work like this very simply this is how it works first when you suck what do you remove for the first Split Second you remove air right when you remove air you create negative pressure inside the straw what does that mean okay positive pressure is this you take a water bottle you blow air into it as hard as you can you're creating pressure inside and that causes the water bottle to expand okay because that's positive pressure you're putting pressure inside the water you're putting air pressure inside the water bottle negative pressure is the opposite when you suck air out you remove all of the air so what you're doing is by removing all of the air now you're pulling on the on the side of the bottle and you're causing it to pull inwards collapsing the water bottle okay so when you remove the air now you create this negative pressure this negative pressure means there's no more air inside and so what you're doing now is you're pulling on the wall of the straw or the wall of whatever you're sucking out of your foot you're trying to pull this wall inwards because there's no more air to pull out so now it has to pull on this wall or it has to pull from down here so if the wall of the straw is very strong let's say it's like made of bamboo then you're not then the straw isn't going to shut closed but if the straw is very plastic very weak then after you if you suck really hard the straw will shut closed and you won't be able to get water up right the same with the bottle and you suck out a lot of air and the water bottle is plastic you're gonna collapse it if it's metal you're not going to collapse it because the wall is much stronger now so you want to you put your your basically dragging this wall in but if the wall is strong it will stay like that it's fine it won't collapse and then the other spot where you're sucking from is from the bottom of the straw because you can you'll you'll put pressure on the walls but you're also try and bring water from the pool okay so assuming that the straw is strong and you're sucking and the straw is like a normal straw it's a strong straw then water will come up because you've now sucked out all the air so now you suck now you're pulling on the water from the pool okay so now the water will start going up why does the water go up the water goes up because of the cohesion and adhesion property cohesion allows the water molecules to stick to each other so when you suck the water up they stay together you form a column of water instead of just one drop here one drop here the water all come together because they like to stick to each other by cohesion Additionally the water likes to stick to the side of this wall so if water didn't like to stick to the side of the straw it wouldn't want to come up so adhesion is also important the water likes to stick to the side of the straw and to each other and hints you can bring up water pretty easily when you when you drink from a straw so if we understand this concept of a straw and the pool then you'll understand this one very well it's the same thing so basically um if we imagine this right here is the xylem or the thing sucking up the water from the roots you can imagine that um it brings up the water right through the same property so it's such understood the previous slide this one will be easier so adhesion is the water sticking to the side and cohesion is water sticking to itself right that's here notice interestingly how it forms a meniscus A V A V shape that's because at this region of the straw the adhesion is bigger than the cohesion so the water sticks better to the side of the straw than it does to itself and so it forms this v-shape okay other other materials like if it's not water so let's say Mercury then it doesn't work because Mercury doesn't have hydrogen bonding it's not the same that's why water is so special right so imagine if there was no water these plants wouldn't be able to bring up anything to drink okay because other materials don't work the same okay um last thing here is what causes the water to want to come up remember how when you were drinking you suck out air so and then this causes the water to want to come up because negative pressure is created the same thing here the plant sweats and it releases water and stuff out of this little pore and you'll learn about this in another chapter and this causes negative pressure to to be created in the Asylum and this causes water to come up okay so again this is capillary action so now we covered these two adhesion and cohesion very important so they can work individually and they can work together right um we know what they mean so let's move on to the next one solvent property so are you guys still surviving this is there's a lot of information but don't worry it's like I'm trying to make it as simple and as clear as possible and hopefully you only have to um watch a video like this once and and understand it because there's a few words that you'll need to like write down 10 times before you remember it but hopefully the concepts make make sense immediately okay so let's go to the solvent property so if I give you these four people and I asked you to match them who who is more likely to hang out who is more likely to be friends so probably you're going to say the two sporty people and then the two nerdy geeky people yeah that's right right that makes most sense um so this brings me to the idea of like dissolves like or polar dissolves polar what this means is things that are similar in polarity will bind together so polar thing will dissolve polar things so water is polar so water things that are polar will very easily dissolve in water whereas things that are nonpolar will very difficult we'll have a very hard time dissolving water same thing as these people people that are alike we'll hang out together and people that are not alike will not okay so let's look at this okay so here we have the structure of water right again we know it's polar now if we look at this again for the tenth time we're looking at this glass of water okay and we try and dissolve something in it whether or not this thing will dissolve will depend on whether this thing is polar or not whether it is hydrophilic or not so if we take salt salt like this is table salt when you put salt into water it will dissolve if you stir for a while it will dissolve and you won't see the salt anymore so we call this kind of molecule hydrophilic Hydro means water and philic means loving so this kind of molecule is hydrophilic it loves water meaning when you put into water it'll dissolve so what does that look like so because notice notice it's polar let's bring this it's polar right so sodium is positive and chlorine is negative so when you put it in water the positive remember the hydrogens these whites are positively charged so the positively charged will interact with the negatively charged chlorine and that way it will be dissolved so it will not stay on the surface it will actually go into the water and dissolve on the contrary the negatively charged oxygen will interact with the positively charged sodium and dissolve it okay so very important hydrophilic molecules like this like sodium chloride will dissolve in water very well on the contrary there is hydrophobic molecules these are things like fat so if if you've ever tried if you try to put oil into water you notice it forms this weird meshy thing like it doesn't want to dissolve though the oil and the water will separate into two separate compartments right if you haven't tried this you should try it this is because lipids is just that's like an example it's fat fat or lipids science name for fats they are hydrophobic so Hydro again means water and phobic means to fear so they fear water in a sense because when you put them into water they do not dissolve because they are nonpolar right they don't have these charges that can interact with the water molecule to be able to dissolve so that's important to understand most things um are soluble in water that's why water is known as a the universal solvent very very important Okay so let me just make sure about something a good a good example to kind of illustrate this is this one when you look at a leaf right a leaf has a top side and a bottom side so here we got the top side and the bottom side and we got the water inside right now water can normally leave a leaf pretty easily if it's very warm day right so the leaf can lose a lot of water but because of this um this one property so the leaves can secrete a thing called a cuticle let me show you it can secrete this thing called a cuticle and this cuticle is guess what it is hydrophobic what does that mean that means when water tries to leave the leaf it cannot because it cannot dissolve in this thing and then leave they repel each other they are Hydro this this cuticle layer is hydrophobic it hates water so when a water tries to come near it cannot pass okay so it's Hydro so this is very important because this allows leaves to retain water so they don't get dehydrated so this is just an example of where the solvent property also matters okay in terms of plants okay so now we've covered adhesion very easy cohesion we got it and solvent basically take what you got to take away from solvent is that polar things will dissolve in water like dissolves like okay so water will dissolve polar things non-polar things like lipids will not dissolve and it's because of the hydrogen bonding right okay last thing here physical properties let's get this done so there's a few physical properties that we've got to look at um we'll do it one by one and it should make there's a lot of like new words but it should make sense because I have a nice diagram to help kind of illustrate it buoyancy so what is buoyancy let's look at this so water is pretty buoyant what does that mean so when you have you ever gone to a pool or the ocean or whatever and you put a one of these balls these beach balls and you try and press it into the water what happens it instantly shoots out right you can press it as deep as possible and then just shoots out this is called buoyancy so water is buoyant meaning it whatever you try and when something when you try and push something into water if it's not very heavy if it's not very dense like this ball it will push back onto the ball it will press that out of the water okay so that's one property that water has that is pretty interesting okay buoyancy um if you like an easy way to remember this is compare everything to air because is air buoyant no if you put if you press a ball into air it's just gonna fall it's going to fall down to the bottom on the floor right whereas you put we try and shove this ball into water it's going to shoot out so water is very buoyant compared to air so it's easy if you compare to air see here so buoyancy if we had to put it in fancy words it's an upward force exerted on an object placed on a specific medium all they're trying to say is it's when the object shoots out of the water when you press it into that into that material okay the force so we we're only going to care about water so this is like the general definition but we're talking about it with respect to water okay next viscosity okay viscosity so here same we the same we're at the same place the same Beach Place if you if you've ever tried to dive into water what happens you hit the water and you slow down right you don't keep going through the water forever right but have you have you ever tried to jump off a hill I hope not but if you have if you took on if you've um done skydiving or something you'll notice that you don't slow down unless you have a parachute okay you you if you jump off a hill you will reach the bottom for sure whereas if you jump into the ocean even though the ocean is very deep you're never going to reach the bottom you'll maybe go one or two meters deep okay so this property of water is viscosity okay so different materials have different viscosity so Air's viscosity is very low because when you jump through air it doesn't slow you down um whereas if you jump into water it slows you down so viscosity is basically the ability of a medium like water or air or whatever it is to slow you down to prevent you from going through it okay so when this guy dives in the water because the water has viscosity he won't hit the bottom of the floor so easily whereas if this was just air he would definitely hit the bottom okay viscosity so here let's put the actual the resistance of a substance that a substance gives to an object moving through it so it's just like resistance okay and so that's the second one let's look at the third physical property specific heat okay so this one's this one we can all probably relate to water let's say it's a nice summer day and you go to the pool and you just notice gosh it's so hot outside but this pool is cold man it's cold I don't want to get in even though it's so hot so this is actually a property of water so let me give you uh thing here wait a second okay so if we pretend this is the pool and there's heat given off by the Sun what's gonna happen is if it's hot um if it's hot enough you can you can break these bonds so look remember these hydrogen bonds unless you break them the water isn't going to evaporate the water's temperature won't change so if it's very hot then you can slowly break these pawns okay and maybe heat up the water now imagine water didn't have these hydrogen bonds how quickly it would heat up because all these things would just evaporate and become gas and become very warm but because of hydrogen bonding this process takes so long which is why on a very hot day evaporation is very slow and so the water temperature changes very slow so we call this specific heat specific heat is basically um how much temperature a specific medium needs to heat up okay to heat up by one degree so water has a high specific heat it takes a lot that's why it has to be 100 degrees before water actually boils okay wait a second computers going nuts okay um Okay so but this one we can all relate to on a very hot day it takes ages for the water to heat up even though it's super hot that's just because water has a high specific heat so let's put the definition here so the specific heat is the amount of heat it requires to change the temperature of a substance so water has a very high specific heat because it takes a lot of energy a lot of heat to heat up water okay now the last one like for example let's say um there are other materials other than water that heats up very quickly for example this one okay remember this one this non-polar molecule we looked at before because it has no hydrogen bonding where as soon as you apply heat it heats up very quickly it becomes gas very quickly so it can actually boil at negative 161 degrees Celsius whereas water can boil at 100 degrees Celsius okay now last one here the last property is this one thermal conductivity okay so if you've ever sat in water if you've ever gone to a pool the pool is the same temperature everywhere so if you touch the water of the pool on this side it's going to be this it's not like oh it's cold this side let's go to that side because it'll be warm there water has very good thermal conductivity which means when this area gets warm it spreads and the whole rest of the area will be the same heat okay so um the the thermal conductivity the spreading of the temperature is very good whereas for example so for example if you if you let's say let's say this um if you heat up if there's a heater this side not only this side will be warm after a while the whole pool will be warm because the water put on busy oh so because of because of this fact that the if you heat up this side not only this area will be warm the water has good conductivity which means the heat will travel quickly and easily from this side to the other side and the whole pool will soon be warm right um whereas air let's think about air if you make a fire on one end of a campsite that doesn't mean that the people on the other end of the campsite will instantly get super hot right air doesn't have such good thermal conductivity the heat doesn't travel so well through air compared to as it does in water okay so so that makes so that those are the key physical properties of of water okay buoyancy viscosity specific heat and thermal conductivity now the last thing we need to know is you need to know about these two animals with regards to these specific properties you need to know okay so we got the black throated loon which is like a duck and we got the ringed seal which is like a seal with rings on it and you need to understand how these properties of water apply to these two organisms so for example buoyancy buoyancy what was that again that was when that is the force that water exerted upwards on anything going into the water so water has good buoyancy which means that these things can float pretty easily right so that's how water is useful to these organisms it helps them float what about viscosity so viscosity actually makes life a bit difficult is running or swimming harder running is easier air doesn't have big viscosity which means when you run the air doesn't resist you whereas when you try and swim you have to put so much more effort to move because the water has a lot more viscosity so these organisms had to adapt to be able to overcome this problem of water okay so basically this duck has webbed shape they have web shaped feet right it has like flippers and their body is streamlined so that the water doesn't so they get less affected by the water the same thing for this ringed seal it has specific petal feet right allowing it to swim much better it's like humans for example are not very well adapted to swimming like we will struggle a lot with viscosity we cannot travel fast now specific heat so remember I just said um water's temperature takes a long time to change so it can be very hot outside but the pool can be cold or it can be very very cold outside but the water may actually be warmer you'll be surprised like it may be very cold outside but you might might actually feel better inside the water like you will go in the water when you start getting out you'll be like oh that's cold and you'll want to stay in the water okay so it's the same thing here these organisms live in very cold environments like the Arctic okay and so even though it's freezing outside like negative 50 they can survive in the water because the water is warmer than the outside because the water takes a long time to get cold compared to the outside so not only does the water take a long time to get warm when it's warm outside it also takes a longer time to get cold when it's cold outside okay so that's useful that's why water is actually useful for these organisms because they can survive better in the water than outside because of the water because the water's a bit warmer okay next one thermal conductivity um basically when these organisms you know when you're in water you lose heat if you stay in very cold water for long enough you will lose heat and you'll like die right that's what happens with the Arctic that's what happens in Titanic right Jack goes into water um he can't stay there forever eventually he dies because he loses a lot of heat so the problem is this um organisms like humans are not very well adapted so when we go into water we lose heat exceptionally fast and we will die very quickly why does this guy not die when there's a Titanic crash because he is adapted he has a way of overcoming this problem that water has water very easily spreads like I said remember we talked about the pool water if you heat up this area water on this side will heat up if you cool down this area water on this side will cool down after a little bit of time so the same thing here if if you if this organism is warm the heat will very quickly go from this organism to the surrounding water and the organism with will get colder so they have certain adaptations to prevent this thermal conductivity property that water has for example this guy here he has this oil gland okay and he secretes oil and remember oil all that is it's a lipid it's a fat and remember the this example here um this fat prevents water from exiting the leaf right the cuticle So Adam this animal has a similar kind of idea it takes this oil puts it on its fur or its feathers and when it puts it on its feathers now the water cannot leave so the water the heat from the water cannot escape the water cannot evaporate from its body so it stays warmer it gets stuck inside the body now so that's how that one adapts the black throated loon now this one here the ringed seal it has a lot of fat it's it's chunky it's got It's got some Mass okay it's chubby so because of this um this blubber they call it blubber it's basically just fat Under the Skin again fat right fat and water don't mix so the heat from the water inside your body cannot pass through the fat so they retain the heat very well and therefore they can survive a long time oh this is cringing me a little bit right forgot they've got the black brackets so because of this they can survive much longer than humans because we do not have any of these cool properties to survive in cold temperatures okay so that's it for everything you got to know about water now we just have some I just want to give you some questions so these although this is a new syllabus the questions the content is pretty much the same okay so the IB questions will still apply it will still be the exact same they'll still be useful so I'm still going to give them to you and you'll see it applies exactly to what we learned I'll give you one multiple choice one and one long answer question you can try and do these and see how you do so here which properties explain the ability of water to dissolve solutes the polarity of water molecules is that true the high specific heat capacity of water is that true hydrogen bonding so yeah I gotta find the right one so let's look at this one so what allows water to dissolve solutes so if we go back to this one is it polarity give me a sec let me find it okay here so water is polar right and because it's polar it can dissolve certain solutes right we explain because this molecule is polar as well so they can dissolve so yeah water's polarity is one reason so that's true oh yeah so solutes by the way is something that is dissolving in the water you call that solute so water is a solvent because it's dissolving something and the solute is something going into the water to be dissolved okay now we got this one the high specific heat capacity of water so we learned about the high specific heat is that related to its ability to dissolve something no right that's another property of water it's not related to dissolving anything it's related to uh its heat heat ability and hydrogen bonding that's also true because hydrogen bonding is what makes it polar right so if we go back to this example here we have this polar molecule and we have water it's polar molecule and because of its hydrogen bonding because of this polarity it's positive charge here can attract this negative charge here which is just hydrogen bonding so the hydrogen bonding allows it to dissolve certain things so the answer here would be one and three right so it's going to be okay I told you this one would matter draw a label diagram showing the structure of water three water molecules and show how they interact uh here's the mark scheme so you can take a look at this but because there's no diagram I'll show you the one I made if you can draw this you've nailed it okay if you've draw this you've nailed it let me show you why because um you have to show the V shape like I explained you have to have a line between the O and the H's and label it as a covalent bond you have to have three water molecules and make the dotted lines in between the O and the H's which is the hydrogen bonding and you can have this slight negative charge and slight positive charge and then honestly because there's still there's five options here one two three four five if you just have four of these you'll get four marks so you don't even need all of these just have four of them so that's it for this video I hope everything makes sense on water it's really a huge topic I really encourage you to understand this as much as possible because it's going to help you a lot in other topics water is everywhere it matters a lot if you can understand these things it'll be hugely beneficial