hello everybody my name is Zohir Chowdhury, and today we'll talk about greenhouse effect so what
are greenhouse gases first of all it is very important to understand what is our air composed
of our air has 99% nitrogen and oxygen combined together about 78% nitrogen about 21% oxygen so
together mix 99% the remaining gases are argon and many other gases so oxygen and nitrogen if we
look at a chemical makeup and how they are bonded together the oxygen is bonded double bond nitrogen
triple bond and they're a little bit tightly bond so with respect to moving they're very limited
mobility in the air and as a result of their inability to move as much or vibrate as much
the heat from the earth as it as it goes through them it doesn't get trapped by the molecule the
heat is able to go through the bonds and the gases out into space so oxygen and nitrogen are
not greenhouse gases because of its inability to vibrate in the air on the other hand carbon
dioxide and water vapor two gases they are bonded in a different manner and on a three-dimensional
scale you can see that they have an amazing ability to move for example the carbon in here
can move inward or outward top or bottom same oxygen as well in the same manner and for water
vapor we can also see a variety of ability for this for this molecule to move and vibrate in the
earth because of this unusual ability for these gases these are heat absorbing gases the heat
is able to absorb and as a result they are known as greenhouse gases you can also imagine that you
have this air that is a dance floor oxygen and nitrogen in this dance floor they are not good
dancer that kind stuck there and slowly moving their body just trying to enjoy the moment whereas
carbon dioxide and water vapor they are the light of the dancefloor they are dancing and moving
around and vibrating and and and essentially like very very vibrant so these are the dancing
molecules whereas these are the watcher so what are the greenest gases Dinah's gases are heat
absorbing gases examples are water vapor and carbon dioxide whereas oxygen and nitrogen
because they don't have heat observing property they are not greenhouse gases we can now move to
the greenhouse gas effect now that we understand what greenhouse gases are so what is greenhouse
gas effect that global energy is balanced between incoming solar radiation also known as shortwave
radiation and outgoing terrestrial radiation also known as long wave radiation you do want to make
sure that you understand all of the terminologies solar radiation incoming solar radiation shortwave
shortwave radiation they are all pretty much the same thing terrestrial radiation or long wave
radiation they're the same thing so the balancing of this incoming radiation and the outgoing heat
together makes the temperature of the earth and the reason the earth warms up is because of
this incoming solar radiation so the balancing of incoming and outgoing together determines how hot
the temperature that earth will be this incoming and outgoing can be further balanced by the
effect of cloud by the effect of snow as well as greenhouse gases and the role that the greenhouse
gases play in this balancing of the heat is known as the greenhouse effect so the greenhouse gases
they are all over the earth and covering the earth and these are dancing around all over the
atmosphere and there able to retain the outgoing heat of the earth and keep it close to the earth
just like a greenness hoodoo in the real world as well in very cold areas the greenhouse would
keep the plant inside warmer because the Sun would strike the greenhouse and keep the inside warmer
so a few degree warmer the greenhouse gases are doing the same thing another way to think about it
is kind of like our body we use clothing and once cat cojones gets colder we use more clothing or at
nighttime we cover our body with a blanket so what is the purpose of the blanket what is the purpose
of the clothing one purpose would be especially the colder time would be to keep the body heat
close to the body so upper body feels warmer and the greenhouse gases it's the same thing as a
blanketing mechanism of the earth that is able to retain the heat close to the earth and keep the
earth warmer this heat retained by the greenhouse gases because the earth has always had greenhouse
gases it's a natural effect in the absence of the greenhouse gas effect the earth would be freezing
cold and nothing would exist on earth but because of the greenhouse gases the earth is warmer and we
are able to thrive third is able to keep a very comfortable overall average 14 degrees Celsius
or about 57.2 degree fahrenheit all around the earth on an average the mean temperature but as
more and more greenhouse gases are emitted into the into the atmosphere the earth becomes warmer
and warmer and warmer just like covering yourself with more and more blankets when you don't want
to and the earth gets warmer and this warming that is happening because of more greenhouse
gases that are that are entering the earth very very fast is known as the enhanced greenhouse gas
effect so the natural greenhouse gas effect is the effect that earth produces by itself
from the greenhouse gases that are present in the air the enhanced greenhouse gas effect is what is
produced when you have more and more greenhouse gases that are emitted for example from human
activity such as burning fossil fuel or other types of human activity such as deforestation
so what what are the greenhouse gases here are some greenhouse gases we already talked
about - water vapor and carbon dioxide he said water vapor and carbon dioxide we have methane
nitrous oxide sulfur hexafluoride and ozone all of these are occurring naturally as well as from
human activity on the other hand the bottom three in here are only coming from human activity such
as CFCs HFCS and pfcs chlorofluorocarbons hydro fluorocarbons and peripheral carbons they are
only coming from human activity typically from industrial production heating cooling activity
another activity that we do on indicate an industrial scale so let's do a quick concept
check which of the following molecule do or does not warn the earth by trapping Heat exactly oxygen
it's not trapping Heat the other ozone carbon dioxide does another quick concept check which
of the following molecular molecules were more warms the earth by trapping Heat exactly e all
of the above because nitrous oxide ozone and carbon dioxide all three are greenhouse gases
alright so that's a quick introduction to greenhouse gas effect thank you for