in this particular video we are going to be looking at um the properties of water the characteristics of water and we're gonna see how these characteristics relate to the importance of water in life so we've established that water is important we get that part but why exactly is water important and for this particular video we are going to be focusing on the importance of water for humans what is important for all living organisms plants bacteria even algae but our main focus will just be on humans now before we go into the properties of water let's look at a bit of revision okay I'm going to also Link in uh the previous video where we talked about water uh we remember that water actually has two hydrogen atoms and one oxygen atom joined together by covalent bonds the hydrogen atoms have a partially or weak positive charge and the oxygen side has a partially or weak negative charge and if one water molecule is nearby another water molecule the oxygen end which is partially negative can interact with the hydrogen and which is partially positive uh and they can basically develop something known as hydrogen bonds and this exhibits and this allows one water molecule to be attracted or to cohere with another water molecule and that is just known as hydrogen bond and here's the thing the hydrogen bond basically influences the importance of water so the fact of the matter for today is because of the fact that water is able to form hydrogen bonds it makes it important for humans and also other living organisms obviously so you might be thinking so what's the big deal about hydrogen bonds why is it that because water can form hydrogen bonds with each other it makes it important for us right so if we were to ask a question why is water important for humans the one the simplest way of just basically explaining this to humans one aspect of water is that water makes up at least about 50 of our blood and why is blood important in our body we know that blood is important in our body because blood carries all the necessary substances required for us to be alive we are going to be talking about blood in chapter 8 which is um I don't know when I'm gonna do a video on chapter eight but hopefully I'll talk about it so I guess I'm just basically throwing out a a microscopic view of blood this is what we see of blood under the microscope as you can see that you can see the red blood cells the white blood cells um over there and the parts where I'm highlighting which is the blue color area is known as the plasma and plasma is mostly just water okay so plasma makes up at least about 50 of our our blood and plasma is just mostly water one of the Plasma's important function is to carry dissolved substances examples of dissolved substances that your blood carries are things like glucose amino acids and salts so you see for the plasma to be able to carry glucose amino acids and salt among other things these things need to be able to dissolve in water and can these things dissolve in water oh yes they can because if you remember all these three substances that I'm lighting over here are hydrophilic so one of the importance of water is water is a solvent in some books they'll also basically refer to water as a universal solvent by definition a solvent is basically anything that is able to dissolve solutes now in a previous video that I've mentioned I'm putting up the link and you can also see it in the description I didn't mention to you that many different types of molecules are able to dissolve in water for example I used sodium chloride as an example where the sodium chloride had a positive charge and a negative charge and the positive end is able to interact with the water because water has a partially negative charge and the negative n is also able to interact with water because water has a partially positive charge which means to say because salt is able to interact with water it is able to dissolve in water sugar for example glucose is also able to dissolve in water because sugar is a polar molecule and because it's a polar molecule or because it's a Charged molecule it is also able to interact with water's charges so what's the big deal uh if water is able to interact with like you know sugar salts and amino acids because they're able to interact with the water they are able to dissolve in water they are referred to as something known as hydrophilic and because they are able to dissolve in water wherever the water moves the salt sugar and amino acids will follow so if the water moves to the left the sugar salt and amino acid will also move to the left wherever the water goes the sugar and amino as it follows the animation is quite poor I'm really sorry for that I do not know how to animate stuff but the point of the matter is just basically this wherever water goes the dissolved substances will also follow which means to say water basically acts as a transport media which is why our blood is 50 water because many things will dissolve in the blood and the blood can then carry the substances throughout our body for example glucose amino acids and salt and remember the reason why water is a fantastic solvent is because water is a dipole water can interact with other polar molecules as well now another importance of water is high specific heat capacity now I have a lot of students who aren't able to understand high specific heat capacity so I'll find my best to teach this concept okay so this is my situation when I say it's a situation this is just my example you do not need to memorize this example by the way but it helps you understand what high specific heat capacity means so in my example over here we have two beakers one on the left one on the right the beaker on the left has 100 MLS of water H2O and the beaker on the right has 100 ml of ethanol which is an alcohol now both the water and ethanol are set at 36 degrees Celsius so both of them have the same volume and both of them right now have the same temperature now imagine for a minute if I wanted to increase the temperature of water to 37 degrees Celsius and also imagine if I wanted to increase the temperature of ethanol to 37 degrees Celsius now logically speaking if you want to increase the temperature of something what do you do well it's easy you just heat it up okay you just apply a bit of Heat and the temperature will go up this is my favorite question to ask students imagine if I were to just add a low amount of heat and that low amount of heat was able to increase the temperature of ethanol to 37 degrees Celsius now will I need the same amount of heat to also increase the temperature of water and a lot of times students will answer yes well if you have this amount of heat to increase ethanol by one degree Celsius you should also logically have the same amount of heat to increase Water by one degree Celsius but that's the weird thing we find out that you actually need a higher amount of heat to turn 100 mL of water to 37 degrees Celsius isn't that a bit weird because you just need a low amount of heat to increase the temperature of ethanol but you need a higher amount of heat to increase the temperature of water even though both of them had the same volume so this surprises a lot of students okay this is a very weird concept what it means is you actually need more energy to make water's temperature increase by understanding this we then can basically say that water has a higher specific heat capacity what does it mean by a higher specific heat capacity water basically needs a large amount of heat two raise its temperature by 1 degree celsius all right but why though why is it easier to raise the temperature of ethanol but it's harder to raise the temperature of water and some of you may have guessed it has something to do with the hydrogen bonds now so I'm just basically drawing out some water molecules over here and you can see the green colored dotted lines and those are just the hydrogen bonds now a bit of lesson on chemistry what is the definition of temperature the definition of temperature is the average kinetic energy of the molecule by the way and if you remember your Chemistry if you wanted to increase the kinetic energy of a particle what do you need to do well obviously you need to heat it now imagine if I wanted to tell the water molecule I wanted to tell the water molecule as though I can to move faster the water molecule is going to say I can't move any faster the reason why it can't move faster is because it is bonded by hydrogen bonds with other water molecules as I've highlighted over that so if you want to make that water molecule move faster you first need to have extra heat you have to apply extra heat to the water molecules to break the hydrogen bonds only after you have broken the hydrogen bonds that's when the water molecule is able to move faster so you need to heat it up to break the hydrogen bonds you also need to heat up the water to increase its kinetic energy and thus it causes water's temperature to increase so long story short to summarize this water can form hydrogen bonds with each other a lot of heat is required to break those hydrogen bonds and to increase water's temperature which means to say water has a high specific heat capacity okay so so far so good we understand that first three parts but again why is this good for life this is fantastic for life because let's look at uh let's look at the situation over here now imagine if you were in a room you were in a cold room and your body temperature was at 37 degrees Celsius now you walked out of the room and you're standing under the hot sun while you were in the room your body temperature was 37 degrees Celsius but the moment you go out of the room you're standing under the blazing hot sun what happens to your body temperature so will it increase will it just suddenly Skyrocket to become much higher no it for the most part remains at 37 degrees Celsius it doesn't instantaneously go up because your body contains water and even though your body is absorbing the heat the water in your body is resisting the temperature change it is not easy for your body temperature to increase because water has a high specific heat capacity so the temperature of water in your body does not easily go up is this good fantastic because you want to make sure that your body is constantly at a stable temperature that does not easily fluctuate which is at 37 degrees Celsius so our body temperature does not change easily to environmental factors another very important factor is I'm just basically drawing a pond with fish and some seaweed over there and imagine again if the temp if the sun is shining into the pond will the temperature of the water in the pond just increase no it won't the temperature remains fairly stable it does not easily increase so aquatic habitats basically remain stable so as you can see over here by just having hydrogen bonds water temperature does not increase and it makes it a very stable molecule which is important in life the third concept that we are going to be looking at is water having a high latent heat of vaporization now what does that concept actually mean latent heat of vaporization is just the amount of heat energy required to change liquid water to Vapor so if you have liquid water if you want to turn it into vapor you need to apply energy the amount of energy needed to turn liquid water into water vapor is called the latent heat of vaporization and when you say water has a high latent heat of vaporization water requires a lot of energy to convert it from liquid to water vapor or gas again let's look at the situation it's very hard to imagine it until I simplify this now imagine this Square to be a human body I know the human body is not shaped like that but this is just how I want to represent the human body and this human body is full of heat the heat is represented by the red dots now the red dots are not pimples by the way the red dots represent heat the square represents the human body all right now so we have two human bodies one at the top one at the bottom both of them are 38 degrees Celsius okay now think about it 38 degrees Celsius is it good for the human body uh depends okay but for the most part for the sake of theory let's just basically say that 38 degrees Celsius is not good for human body we should return the body temperature down to 37 degrees Celsius all right okay now one way of basically doing so so how does our body return the body temperature back to normal now imagine at the top the human body at the top there's water on the surface okay represented by that blue color glob and for the human body at the bottom there's ethanol at the surface just for the fun of it and it's the same amount of itador all right now because water has a high and the water is in liquid form by the way okay because water has a high latent heat of vaporization water is able to absorb a lot of heat from the body a lot of heat is basically absorbed into the water on the surface of the body only then will the water turn into vapor as represented by those uh ribbon like blue like structure and you can see the heat is being carried from the body look at the amount of heat that is left inside the body the amount of heat left inside the body is much lesser it's at 37 degrees Celsius that's a good thing so the water on the surface of of our body has absorbed the Heat and it has evaporated but because water has a high latent heat of vaporization it was able to absorb a lot of heat before it evaporated that's a good thing so it cools the body down ethanol however has a lower latent heat of vaporization so will it be able to absorb heat yeah it will be able to absorb heat but it doesn't absorb a lot of heat and it just absorbs a little bit of heat and it has already evaporated and look at the amount of heat left inside the body there's still a lot of heat inside the body which is about 37.8 degrees Celsius so did it manage to cool the body down so much no I don't think so all right which is why we sweat water we do not sweat ethanol because water is much more fantastic at cooling the body down than ethanol although I do know that some people would pay to sweat a lot of ethanol from the body I don't think that's possible okay and I don't think that's healthy too right so um by understanding this water can absorb a lot of heat before turning into vapor and that's a fantastic thing and that is why water has a higher latent heat of vaporization but why though why does water have a high latent heat of vaporization again it has something to do with the hydrogen bonds I'm throwing up the skin surface and the weight color dots represent the Heat and I'm also going to draw a dollop of sweat on the surface of the skin or a drop of water on the surface of the skin and you can see the water forming hydrogen bonds with each other again it's the hydrogen bonds okay now and the hydrogen bonds I've highlighted in these yellow highlights I hope you can see them quite clearly now if you want the water to evaporate first extra heat is needed to break the hydrogen bonds between the water molecules so you can see that the heat basically breaks the hydrogen bonds right it breaks it apart and then extra heat will then increase the kinetic energy of water causing it to evaporate there we go it evaporates so a large amount of energy is needed to vaporize liquid water in this case and why is this good this is fantastic because water is a fantastic coolant for the body it is able to absorb a lot of heat from our skin and reduce our body temperature especially when our body temperature is higher than normal I'm just going to show you another one here you can see those uh heat particles those heat energy breaking the bonds and the heat energy causing the water to evaporate it goes up and then another the heat also breaks those hydrogen bonds and it causes that water to evaporate and look at what happens to the amount of heat inside the skin the amount of heat inside the skin has reduced and therefore it reduces our body temperature this is why water is a fantastic molecule which has pre-extremely important characteristics it is fantastic as a solvent because many things can dissolve in it and because it's fantastic as a solvent it is used to transport substances for example in our body like blood water has a high specific heat capacity which means to say it has to absorb a lot of heat before its temperature can increase which means to say the temperature of water remains stable and our body's temperature remains stable even if we were to walk in different environments whether it's hot or cold and the third thing is water has a high latent heat of vaporization which means to say it takes a lot of heat energy to convert water into vapor which means to say the water is able to absorb a lot of heat from our skin before evaporating thus doing a fantastic job in reducing our body temperature that's basically what we have to understand about the properties and characteristics of water and why it's important for life