grade 10 geography atmosphere explained in detail: thundereduc

0:03 [Music] good day lers uh welcome to the presentation for grade 10 uh presentation on the atmosphere under the atmosphere po stud area we be looking at the composition of the atmosphere and by composition we'll be looking at the different constituencies which make up our atmosphere and also in addition to the composition we also want to look at

0:51 the structure of the atmosphere by the structure will be uh looking at the different layers which make up the atmosph spere all right um so before we venture into the discussion in detail we want to start by simplifying what the atmosphere is by defining that geographical concept of the atmosphere right basically we can Define the atmosphere in simple terms in the most simplest terms is the layer of gases surrounding the Earth's surface right if I can take you back maybe if you can still remember the internal structure of the earth we'll be looking at how the different layers that make up

1:38 the Earth are arranged from the Earth surface getting into the interior of our Earth but in this instance when you're looking at the atmosphere we are now looking at that layer which is composed of gases and suspending particles above at the Earth's surface meaning to say from where the different continents are located we are in the atmosphere because we are exposed to the different gases which make up the outer part of our Earth surface that is basically what we refer to as uh the atmosphere right um and we also noted that um the density of gases decrease with

2:26 height as one move away from the Earth surface right meaning to say that we also tend to find that the gases that are in the H atmosphere they are less dener than the particles of gas which are closer the Earth surface right um it implies that um less dense material tend to suspend in upper atmosphere than more denser material which tends to accumulate close to the at surface so the concentration of um a particles which are denser is more concentrated close to the Earth surface and as the density decreases it tends to imply that the particles will suspend in upper atmosphere that's the intent that's the translation of that

3:13 effect that the density of gases um decrease with height as one moves away from the Earth surface all right we said we want to start by looking at the composition given now that we have defined what um the atmosphere basically is we now want to go and look at the composition and we said by composition we are looking at the different constituencies which make up the earth atmosphere all right in the first instance we said the earth atmosphere is composed of Some solid particles Some solid particles we are referring to particles like ice particles like salt

3:58 smoke bon in dust those particles basically they come from the Earth surface then give example of smoke as one of the solid particles which are found in the atmosphere when people do the different activities like when people cause bu fires when people um use the different modes of transportation burning the different forms of fossil fuels uh those fuels they tend to release some smoke as they burn that smoke will suspend and accumulate in the layer of gases which suspends above the atmosphere and also we can talk of maybe dust particles dust particles coming from the Earth surface um we can give an example of when we have a dust storm

4:47 when you have a dust storm it means some soil material which is in the finest form of dust is taken up into the atmosphere and gets suspended in the atmosphere so it becomes a part of the materials that make up the atmosphere so we have talked of smoke as one of the aspects and also we can talk of dust as some of the particles and also can talk of carbon ice and also some salt material can also be found as suspending particles or solid particles which make up the atmosphere right then we go to number two aspect number two which is a constituent of the atmosphere we have

5:34 the liquids and this liquid here we are referring to water we also tend to find that in the atmosphere we have water accumulating there in the atmosphere right and in this instance here if we talking of water in the atmosphere our core Focus remember we will be referring to mainly the water vapor the water vapor which comes from evaporation process from the different water bodies we have the different water bodies from which when there's evaporation that GES water G to suspend in the atmosphere in the form of a water a vapor so we also have liquids in the atmosphere predominantly in the

6:19 form of water vapor right and lastly we have gases our gases are also prevalent as a constituent of the atmosphere they are also found in the atmosphere as one of the major constituencies which make up the atmosphere and under this gases we need to make a clarification number one we have what to call permanent and number two we have what to call variable right and what you call permanent in other instances is also called constant right what it means here when we talking of permanent gases we are saying those gases they do not change in their composition content meaning to say they are permanent in the atmosphere

7:05 they do not change and they are constant in terms of their constituency like if you are to look at them using percentage their percentage does not change from a given symbol of the atmosphere their percentage maintains the same those are what we call the constant or the permanent gases then you also have what we call the variable when something is variable or is varing it implies that it changes meaning to say the composition of such gases which we regard as variable it changes from time to time from space to space me need to say if we take a symbol of the atmosphere the amount of gas that you're going to find at a given geographical space might not be the same as what we will find at some

7:52 other given geographical space that is the variable part we are talking about here or the changing part part the gases They do change in their constituency or in their levels of composition if you to express them maybe as a percentage of the total of the whole atmosphere you tend to find that they vary from place to place which is geographical variation and also they tend to vary from time to time right that is basically what is of concern to us in summary is um the constituencies or the composition of the atmosphere what we need to do now are given that we have seen the picture of what makes up the atmosphere as the constituencies of the atmosphere we need to progress and look at um how those

8:41 different components uh contribute in terms of the levels of their contribution as a percentage to the total amount of uh components in the atmosphere right I go to the gases in the atmosphere we mentioned that under gases we specifically have gases which we regard as permanent or which we regard as constant and those that we regard as variable gases all right um our major uh gases which are okay as permanent in the atmosphere we have nitrogen and oxygen and also we tend to have agon which is also regarded um in most instances um

9:27 as one of them gases which are regarded as noble gases right uh let's start by looking at um the gas which we regard to as oxygen as nitrogen we start with nitrogen in this first instance right if we check our nitrogen it's indicated that nitrogen has got a constituent of 70 8% it has a fixed quantity of 78% given that we said is permanent it means that it maintains its level or it maintains it content composition in the atmosphere his content composition is pged at 78% which implies that is the major constituent of of the gases in the atmosphere is the major constituent with

10:14 78% of composition in the atmosphere and we also are mentioned that we have oxygen oxygen is at 21% and that 21% that's the composition content for oxygen as one of the permanent gases then lastly our Aron is at 0.9% so basically those are some of the major gases which we regard as a permanent or constant gases in the atmosphere and um we can proceed to look at what we call the variable gases in the atmosphere right our variable gases you can see here

10:59 um they are coming in the form of a water vapor and a carbon dioxide that is our those are the two major examples of our um variable gases right we mentioned about water vapor being a constituent of the atmosphere and we mentioned that water vapor comes from um the evaporation process from different water bodies predominantly and also it can come from EV transpiration the different forms of vegetation right it means the content of water vapor in the atmosphere does not maintain the same the percentage composition does not maintain the same why does it differ right you tend to find that it differs from space to space and also it differs

11:45 from time to time given the different weather elements that will be experienced in a different geographical space and at some different time so what will happen here uh if for example we are having higher temperatures and maybe we are having a free flow of wind those factors they will facilitate High evaporation rates and it will mean that the composition of water vapor in the atmosphere that particular geographical space will be higher because we have weather elements which are facilitating the evaporation of processes which contribut towards the conversation of water paper in the atmosphere if they nonexistent it also means that the level of water vapor will be limited say for example we are in a cold region colder

12:31 regions they are predominantly occupied by cold air masses in cold air masses you know that they will be are dry so the content of water vapor in the atmosphere will be limited in those regions while it it will be higher like for example in warmer regions because evaporation rate will be also higher so the level of water vapor in the atmosphere tends to vary from time to time end from a geographical space to another geographical space that is with water vapor right and then we can proceed to our our next constituent which falls under that component of um variable gases we said also have carbon dioxide right carbon dioxide um with a

13:19 chemical presentation of CO2 right we are saying here for carbon dioxide what happens with carbon dioxide uh you know predominantly released from the Banning of fuels and also carbon dioxide a variable gas in the sense that the processes which lead towards its contribution in the atmosphere they tend to differ from space to space and also from time to time let's give an example of the bending of fossil fuels right uh maybe you can check compared to geographical spaces an a industrialized area there has a rural set up the country side you tend to find that the concentration of carbon dioxide will differ because of the different

14:05 activities which dominate in the given geographical space if for example having an urban area area is industrialized also you tend to find that the level of burning of fossil fuels will be much higher compared to the countryside we have so many forms of Transport which will be moving around burning fossil fuels we have Industries which will be operating those Industries will be contributing also towards the production of carbon dioxide as they B the fossil fuel so the concentration will be higher if we to take a sample of the atmosphere from an industrialized area with compared to the rural Countryside so it's also a variable gas which tends to differ in composition from time to time and from given geographical spaces that

14:53 is with carbon dioxide then the graph to the extreme right is just giving a summary of the different um compositions of the atmosphere using a p chart presentation where you can see that our nitrogen is indicated here as 78% which is taking the bigger chunk of the pie chart presentation then our oxygen you can see at 21% is also taking a relatively a bigger part then lastly our carbon dioxide you see it's having the smallest one on that Pi chart and then other carbon dioxide and other gases combined together they

15:40 contributing just one% of that total composition of the atmosphere so our major concern if to check on this presentation is that of nitrogen this is the gas which is has having the biggest percentage or contribution towards the composition of the atmosphere followed by oxygen and lastly carbon dioxide combined with other minor gases they all form one% of the total composition of an atmosphere right um that's the P presentation it's just a summary of how those different gases contribute in percentage form towards the composition of the atmosphere right um then we need to make

16:26 an analysis and see why those gases are important um to us as a living beings on the Earth's surface we being beneficiaries of the existence of the atmosphere why are those gases important or what's the rational for having those gases are they of importance to our human life or they are just gases which have no bearing on our human life right if we check um nitrogen nitrogen is important for plant growth right that is um the rationale for nitrogen plant growth is very important to Aid in the growth of our plants I think um if you can still remember from the previous

17:12 studies you remember that we have what you call the nitrogenous fertilizers right those fertilizers we are saying they are rich in nitrogen and nitrogen being it the major component of those um fertilizers it means it's an important component towards the growth of plants when you talk of nitrogenous fertilizers right it means those fertilizers will be rich in nitrogen and that nitrogen is the one that will facilitate uh the growth of uh the plants and also if you talk of nitrogen fixing which happens naturally it's also a component where nitrogen is extracted from the atmosphere and is fed to the soil and

17:59 this very important process which results in then enrichment of soil which is beneficial for the growth of our plants right that's basically with nitrogen and we have to remember that our nitrogen we said is the major contributor the percentage ction of the atmosphere which is ranked at 78% then we go on to oxygen oxygen is important for cell respiration and for combustion and or you are burning right cell respiration the respiration process living organisms they respire so for respiration to take place we have to feed in oxygen into the system we breathe in oxygen as living beings which

18:46 means that without oxygen we won't be able to respire we won't be able to sustain life because we need that oxygen for the process of respiration so oxygen is a key element towards our human sural or towards animal survival because of the fact that is the gas which supports the process of respiration and also for combustion right for combustion to take place it needs to be supported by the presence of oxygen for complete burning to take place we need oxygen to be present in the process so that we have what to complete combustion otherwise if it becomes incomplete without carbon without oxygen we will be having the release of the harmful carbon monoxide

19:32 from the process so for complete burning to take place we need also um the presence of oxygen so it's a key element or it's a key gas which is very important towards sustaining those two processes of burning and that process of cell respiration for animal life and also you also have to figure out where the oxygen comes from remember we have the process of respiration by animals and we have the process of photosynthesis by plants these two processes they interchange the gases respiration uses oxygen to release carbon dioxide while it's photosythesis on the other side it takes in the carbon dioxide to release oxygen so those two

20:19 processes are interrelated in the sense that a byproduct or of one becomes the input to the other so the output of respiration which is carbon dioxide it's an input on the side of photosynthesis when vegetation photosynthesized they take in that carbon dioxide to use it for photosynthesis only to release oxygen at the end of the process while is the oxygen is also required for respiration and at the end of the process carbon dioxide is released right that is basically with oxygen then we can proceed to our next gas which is Egon Egon is mainly used used for industrial purposes such as welding and manufactur of electrical bulbs it is

21:05 also known as a noble gas right that's the Ral of agon it's an industrial gas it's a gas of industrial importance meaning to say it can be used for those different industrial purposes like in welding and in the manufactur of electrical B and we said it's a noble gas meaning to say it's a nonreactive gas in atmosphere it does not have any reaction in the atmosphere that is why it's regarded as a noble gas right we move on to water vapor water vapor which you mentioned that is predominantly coming from the process of water of evaporation then why is it important for us to experience our rain formation we need water vapor in the

21:54 atmosphere when warm and moist air is posed to rise that moisture when it reaches what we call the je Point temperature it converts its form from being a gaseous state to become water droplets that we see as our clouds so it can only happen that we receive rainfall after we have a situation where we have moist air ascending to higher altitude reaching due point and the moisture condensing to form clouds which will mean that without water vapor in the atmosphere we won't be experiencing any form of precipitation coming to us on the Earth

22:42 surface so water vapor is very important for the climatic process of rain formation I think you can still remember we can still figure out from the previous discussion you talked about the different types of weather of rainfall which are realized the likes of orograph traffic or relief rainfall the likes of cyclonic or convectional rainfall and the likes of Thal rainfall those rainfall if you check they are as a result of water vapor being present in an air parcel in the atmosphere as the air parel is ascending is going up towards a lower towards higher altitudes the temperature gets lowered and the water vapor will condense and will result in De formation of water droplet

23:29 which we see as clouds that will produce rainfall right we move on to carbon dioxide as one of the constien again carbon dioxide we said it vares because of number of people combustion amount of vegetation etc those are the determining factors or the factors which control the amount of um carbon dioxide amount of number of people we said remember respiration people respire as they do respiration they release carbon dioxide which means in areas which are highly a populated it also means the concentration of carbon dioxide will be higher and combustion the burning process where there's high levels of burning like in the industries and where there is high

24:15 traffic volume you also tend to find that the concentration of carbon dioxide will be higher and also amount of vegetation we said vegetation is responsible for using the carbon dioxide in the atmosphere for the process of photosynthesis which means when there is high concentration of vegetation the carbon dioxide in the atmosphere will be effectively used for the process of photosynthesis and it contributes towards the reduction of the composition of carbon dioxide for that particular geographical space because of the presence of a vegetation which tend to utilize in um carbon dioxide or for the purpose of photosynthesis right so

25:02 that's basically a picture on the translation of those gases and trying to figure out how we get those gases and how they can vary if they are variable and the rational form the constant are gases which we said they do not change or the permanent are gases which do not change in the level of composition of them in the atmosphere right uh we need to move on and have a discussion on the importance of the atmosphere what's the Ral for the atmosphere why is it important that we have the atmosphere covering us on the earthy surface right um the first one which is most definite is it contains oxygen which is essential

25:47 for respiration in human the process of respiration we described it prior to this it means um if they wasn't at the atmosphere with its compostion of oxygen then life on Earth wasn't going to be possible it wasn't going to be realized because without oxygen it means humans cannot respire and without respiration there is no life which will mean that the atmosphere plays a very big role in providing oxygen for the sustainance of a human life on Earth surface and also condensed carbon dioxide and what's the Ral for carbon dioxide which is important for plants to

26:33 grow we said plants they do photosynthesize and in the process they tend to use carbon dioxide so it's also another rational of the atmosphere to provide carbon dioxide which is important towards the sustainance of plant growth and number three it St that it act as a blanket around the earth a blanket looking at a cover material here uh remember the sun produces harmful Rays the heat which comes from the sun comes in the form of what are called the ultra violet Rays or the UV arays which come in the form of a short wave arays the suns are it the sun's um

27:23 radiation is regarded as the shortwave radiation which is harmful towards human life the short wave or the ultra violet Rays so this ultraviolet race um is they need to be reduced in terms of their effect as they get towards the Earth's surface if the Earth was to hit directly towards the earthy surface there was going to be so many complications which will be caused by the level of heating which will be have have been received from the Sun so the atmosphere act as a blanket which means

28:10 the atmosphere protects us on the earthy surface from the effect of the dangerous UVS which will be coming from the sun the sun will be producing high levels of radiation which will tend to affect life on the Earth surface but because the atmosphere is there it will filter the impact of those UV rays to protect us on the earth that is why we are saying it act as a blanket it's a cover which is protecting life on Earth from the dangerous or the harmful effect of the u r coming from the Sun then it also protects life on Earth we are also referring to the armful effect which

28:55 comes from the radiation of the Earth of the sun there are so many harmful phenomenons which develop in the atmosphere which will be filtered by the atmosphere which will mean that life is is being supported by the presence of the atmosphere and you are being protected from the harmful effects which arise from the upper atmosphere right that is on the importance of the atmosphere in um brief or combined picture of the whole atmosphere why we saying the atmosphere is important as a component of the earth structure right

29:41 um and after this we have seen the Ral of the atmosphere we need to move on and look at the structure of the atmosphere by the compos we looking at what makes up the atmosphere what is it that is in the atmosphere right now we want to look look at the structure by the structure we now looking at the different layers which make up the atmosphere the atmosphere is not a uniform H does not have a uniform structure meaning to say it is not comprised similarly throughout but is comprised of some different sections which make it up so we want to look at the different sections which make up the Earth's atmosphere right what is

30:26 indicated here is um a brief uh picture of the layers which make up the atmosphere right um I will try to illustrate I'll try to explain using the diagram indicated here right if you check our diagram how the diagram should be read when you are reading this diagram you should be familiar with what is presented on the horizontal and what is presented on the vertical axis if you are to check here on the horizontal axis you can see that temperature in de C it's presenting our temperature in degrees celsus and on the vertical axis that is our altitude or our height right

31:14 so what it means here is we have our temperature readings on the horizontal AIS starting from zero this is uh 0° C the next one is 20 40 60 going towards the positives and from Z we have - 20 - 460 going towards the negatives so it means our temperatures are ranging from extreme negative and going towards extreme are positive right so the first layer that we have on the earth structure is this layer which is called the tropos sphere it's called the troposphere that is the layer which is most immediately

32:00 above the earthy surface on which we are situated all continents are situated within this layer and all human life is sustained by this layer this layer which is called the troposphere is one which is lowest according to the explanations given here we are now referring to that illustration here he's saying the troposphere is the lowest layer uh this is where we live because we are just above the earthy surface it means the earthy surface is presented where these temperature markings are just on top of this we are in the troposphere and is where weather okay for us to experience rain formation for us to see cloud formation for us to realize all those different weather elements they do happen within this first layer which is the tropo sphere

32:45 right and we want to analyze this line which is indicated here this line that you are seeing the white line here which is going upwards like this is the temperature or profile the temperature profile this is a temperature reading we are comparing temperature on the horizontal scale on the horizontal axis versus the altitude on the vertical axis here so what it means here is um this is a reading of temperature starting from the ground surface starting from the ground surface we have a temperature let's say on this here you can see our zero Mark for temperature there our 20 is there which

33:31 means our temperature here we can estimate it at plus or minus maybe 12 or 15° C starting from the Earth surface and if our altitude is increasing here our altitude is going upwards in kilomet from Z to around 10 you can see that the temperature when we reach the 10 kilom altitude Mark our temperature has dropped significantly to around netive 40° so this is what we refer to as a negative temperature profile which impli that in the troposphere if you go to higher altitudes the temperatures are going to decrease the ground surface or the

34:16 earthy surface has got higher temperatures than places in Upper altitude th the temperature profile in the troposphere is negative meaning to say the higher you go the temperatures will get lower thus the essence of the temperature profile within the troposphere then what will happen as we as the reason as to why the temperature profile is like that we are going to discuss it in detail when we do the heating of the atmosphere the heating of the atmosphere gives us a clear understanding of why the temperature profile is negative why is it much water close to the Earth surface than in the upper atmosphere the troposphere right then if we continue with the temperature profile you see that here there is a white

35:03 marking which is written tropo POS this one here is indicated the tropo POS what is it that we call the tropo POS that's the upper limit boundary of the troposphere we are moving from one layer to the next layer we are transiting from one layer to the next there is a boundary which marks the end of that particular layer so it's troposphere then when it ends when we are to approach the next the next layer we reach what is called the tropo force that's the boundary the upper limit boundary which marks the distinction between the troposphere and the next layer right after the next layer we now move on to um what is called the

35:52 stratosphere that's the next layer on the structure of the atmosphere and if you can check here our altitude is still increasing the trop Stratosphere from around 20 kilm getting to around 50 km here around 20 going to as high as 50 so you can see this layer is much more denser than the previous layer the troposphere is thinner compared to the stratosphere and it is within the stratosphere where we have what is called the ozone layer and the ozone layer is also part of a discussion to follow which we're going to focus on the ozone layer on its own and see its rationale its importance and what human activities and what humans are doing

36:38 which is contributing towards what we call O depletion and the likely impacts and the strategies to avoid the depletion of oone that is a discussion on its own but for the sake of discussion of the O of the structure of the atmosphere you should just mind that there is also the oone layer which is found in the Strat sphere right there's a concentration of that gas which is called ozone within that layer of the stratosphere then we continue if we check the temperature profile it's now reversing the temperature profile is now positive in the stratosphere meaning to say with increasing altitude the temperature is also increasing if you check starting from here our altitude is increasing from 20 going to 50 our

37:24 temperature was at -40 but here you can see that the temperature is almost close to 0° which means in the stratosphere the temperature profile is now different from the troposphere is now positive as height increases the temperature will also be increasing that's the profile within the Stratos sphere then we reach this upper limit the upper boundary of the Strat sphere is called the Strat H that's the upper limit boundary we are now transiting from the Stratosphere we are moving on to the next layer of the atmosphere right so um that's basically the Strat pose

38:10 right and we move on to the next layer after the stratop pose the stratop POS is followed by a layer which is called the meso sphere which is the third layer as we come from the Earth surface mesosphere what happens in the mesosphere what we should be worried about is the temperature profile how does the temperature change with increasing altitude within that layer right if you check from the stratose here going towards the mesop here which is the upper limit bound you can see that the temperature profile is negative as height increases the temperature is decreasing and is decreasing sharply if

38:55 you try to check the temperature here is plus orus 0° C at the strose but the moment you reach the end of the mesosphere you find that the temperature is very low excessively low temperature to around 90° C if you check the reading here plus orus 90° C so it means the temperature H drops uh very significantly from 0 to 90 that is a very big change in temperature with altitude so that's the typical um conditions in the mesosphere then we reach the upper limit layer which is the

39:40 mesoa and from the mesop we go to what we call the thermosphere right thermosphere here is the fourth layer coming from the Earth surface thermosphere it implies that this region here is having higher temperatures is having excessively high temperatures from the mesop the temperature was aroundus 90° C but if you check as we go up to the end of the hemosphere the temperatures are very high above 60° cus which is a still increasing with increasing altitude there is a positive temperature profile in the thermosphere implying that if we keep increasing altitude within the

40:25 thermosphere the temperatures will get excessively very high and that will be the um translation of the conditions within the um thermosphere and predominantly the temperatures are caused by atomic oxygen which is responsible for absorbing a heat within the thermosphere that is why the temperatures will get excessively very high and if we are to look at the upper limit of the osphere we again have a pause at the end which is a thermop pause and from the thermop pause we will now be going into space which we refer to as the exos sphere we will be now

41:11 going outside the normal structure of the Earth getting into space which we regard as the EXO sphere right which lies outside the normal Earth structure right um that was with the its structure so in summary what you need to note is you need to note the arrangement of the uh different layers which make up the earthy surface which make up the atmosphere starting from the earthy surface and number two what you need to know is you need to not the temperature profiles in those different layers how does the temperature behave with increasing altitude in those different layers and also you should mind when you are minding about the limit the boundary

41:56 between the layers know that the layer on top the upper boundary is named before is named after the layer below like if the troposphere when it ends when the troposphere ends it ends with the tropo pose then we got the stratosphere it's another layer we are keeping on increasing our altitude it ends again with a pose named after the layer before which is a strat for we go the mesosphere the upper limit boundary is the mesop we go the thermosphere the upper limit is the thermo pose that is how those layers are basically arrange right so um to check on our discussion we just want to

42:41 summarize on the different layers and maybe give a rational what's their importance and how they look like because we now have a picture of how they look like and what makes them up and how does the temperature behave have with altitude in those different layers we just now going over through a summary of the different layers right we start with the troposphere the troposphere is closest to the earthy surface I think that is clear because we said that is the most the uppermost layer above the earthy surface the one which starts as we are moving away from the earthy surface and its height is about 10 kilm around the polar region and 17

43:27 kilometers around the equatorial region right which impli that the upper limit boundary of the troposphere it differs from around 10 km in the polar regions and it also around 17 km around the equatorial regions which impli that it's higher the upper limit boundary is higher is already elevated in warmer regions and is lowered in CER regions and air is densest in the layer that is where we find the heaviest air concentrated in this particular layer of the atmosphere and the highest amount of oxygen and water vapor remember we said this is the layer which supports life so we need oxygen and it's rly available it's highly concentrated and also weather processes we said they take place in the troposphere water

44:12 vapor is a key element towards determination of the weather patterns so we also have it there then temperature decreases with altitude is clear we said the there's a negative LPS rate there's a negative temperature profile which tends to be realized in the troposphere temperature decreases with altitude and is separated from the Stratosphere by the tropos I think it's also clear troposphere we go to tropos then the importance it produces weather we talked about that that all weather takes place within the troposphere the oxygen that we breathe we get it from there and also water vapor which is essential on Earth for it to rainf we need to have water

44:57 vapor which we realize from then troposphere then we also indicated that produces water through rain since weather processes take place in the troposphere it also means that we tend to find rainfall being realized within the very same layer and produces food that we eat remember we said plant life photosynthesis takes place and also respiration takes place so for us to have food either we having food from plants or having food from animals for us to effectively do agriculture we need this layer which supports plant life and also which supports animal life remember on plant life we talked about nitrogen being present in the atmosphere in this

45:43 troposphere so it means plant life is sustained and also the carbon dioxide sustains plant life and animal life is sustained by oxygen which means this layer is very important it contributes significantly towards the sustainance of life through providing food for humans on the Earth right and um we move on to the next layer after the troposphere we said the upper boundary is the tropo P then we go to the Strat spere is located above troposphere yes I think it's clear we have talked about that on the profile and it contains oone layer the O layer we mentioned about the O layer that is a layer which protects us from the harmful

46:29 ultraviolet Sun's race and that one is going to be at Center of discussion on its own the presence of ozone layer and how it is destroyed by human activities and the impact of ozone destruction and what can be done to address the issue right and say temperature increases with altitude right which is a negative temperature increases then we go on to to the importance of um the um the layer of the stratosphere it contain ozes which supplement our oxygen yes and airplanes are flown in this layer right the airplanes they do not fly within the troposphere but they fly

47:16 slightly above the tropo POS within the Strat Sphere for one major reason that remember we said all that t place within the um troposphere which imply that if it is on a cloud day if planes are to fly within the troposphere visibility will be very minimal they won't be able to see through their way so the only way to be safer is to fly slightly above the layer in which weather is taking place to avoid that issue of invisibility which is caused by the formation of clouds within the the atmosphere so the airplanes they tend to fly within the Strat spere slightly above the trop POS

48:04 and we also indicated that the airplanes they use wind in this layer to pick up speed remember the flow of air within that layer is unlimited the air Flows at a FAS velocity which are going to be utilized by the planes to GA the momentum and to GA the speed right basically that's the importance we can summarize the import of the trop of the stratosphere using those three arguments then we go to the third layer which is the mesosphere the mesosphere we are saying it just comes above the Strat pose we got the mesosphere and the mesosphere is stretching from around 50 to 80 kilom above the stratosphere from the Earth surface from about 50 km out after the

48:52 Earth surface to around 80 and temperature degrees is with with altitude in that one a temperature can be 80° C yes which is excessively very low temperatures and upper limit is the meeso force I think that is clear we said after every layer the upper limit boundary is named after the name of the previous layer so the layer concluding the mesosphere is the meso puse why is it important to have the mees sphere in the strcture is it prevents rocks from space entering the lower atmosphere right there are some dangerous phenomenon which can develop from the space which are likely to affect human activities on the Earth surface like for

49:38 example RS are fragmenting from space they are filtered by the presence of the mesosphere that they do not cause harm within the troposphere and timately to Li on the earthy surface then we go on to the fourth layer and this fourth layer remember it comes after the upper limit boundary of the mesosphere which is the meso we go to the th spere an outer layer of the atmosphere it extends from around 80 to me with the space which means we will be now going outside the Earth's structure will be going into space temperature increases with altitude and air particles reach temperature of about 5 5, 00 to around

50:23 1,800 degrees uh Celsius which means the temperatures in that particular thermosphere they are very high imagine a temperature of 1, 800° C that is very high temperature right and why is it important it absorbs high energy radiation from the sun right we talked about Atomic oxygen that Atomic oxygen within the thermosphere is responsible for absorbing some of the high radiation which comes from the Sun and also it prevents rocks from space entering the lower atmosphere like what we mentioned in the um mesosphere right then lastly we look at the EXO sphere which is now an outer

51:09 layer of the thermosphere we are now out of the earth structure we are approaching space it's from 550 km to thousands of kilomet into space we are now getting into space right why is the exosphere EXO we saying we are out side the Spheres out of the Spheres out of the normal spheres which make up the Earth so why is it important it is here that satellit orits the a right uh when you do a geographical Information Systems you're going to look at satellite images you're going to look at satellites how the information on Earth is captured using the satellites those satellites they orbit within in that exosphere so that they have a clear

51:54 picture of what device happening on the earthy surface they capture information from the outer space so basically that's the picture of the composition and the structure of the atmosphere we looked at the structure and the composition of the atmosphere right um that marks the end of our discussion uh we thank you for attending and what is going to be the C Focus area in the next discussion is we're going to focus on the heating of the atmosphere the process responsible for the heating of the atmosphere that is the next discussion to follow this one so for

52:42 today I thank [Music] you [Music] n