MEGHAM (THE CLOUD)—PART 2
Continued from part 1. Dearfriends, I am thankful to Mr Venkat raman Perinthalmanna, forpointing out the mistake- Instead of Edavapathi I had mentioned Karkitakapathi. I am sorry for the oversight. Sincerely, Gopala krishnan 12-1-2011 Reposted on 6-2-2021 the compilation after editing andupdating. R Gopala Krishnan. 9. Why air is cool athigh altitudes? In the last posting we have seen air-absorbing moisturefrom water bodies like lakes and rivers. This air is tends to rise to higheraltitudes where the surrounding air is colder. Atmospheric pressure decreaseswith altitude (Studied in 7th or 8th standards). So whenair rises, it expands in a process that expends energy, which causes the air tocool. 10 How the cloud isformed? Cold air holds less water vapour than warm air, so cloudsare formed when the air is lifted and cooled to the point at which it begins toshed vapour it can nolonger retain. This saturation temperature is known as dew point. 11. Whether clouds are formed at different altitudes? Yes. The altitude of the saturationlevel determines the altitude of the cloud base. The vapour begins to condenseonto airborne hygroscopic particles like dust and salt from sea spray and becomesvisible as cloud. This is simple explanation. This is the reason when we go byflight we see sometimes clouds below or at a very low level than it. Update- Once whenthere was a delay in departure, in a flight from Bangalore to Chennai, heannounced delay doesnot matter much. The flight will reach in time. He started to fly at ahigher altitude. On looking through the window clouds were very lower levelthan flight and sky found blue. 12. Categories of cloud We can see on looking up different forms of clouds. What isthere grouping? Cloud is groupedinto three physical categories: cirri form (mainly detached and wispy), cumuliform or convective(mostly detached and heaped, rolled or rippled), and stratiform (mainly continuous layers insheets). These designations distinguish a cloud's physical structureand process of formation. All these cloud types form in the troposphere or thelowest major layer of the Earth's atmosphere. (This information is help fulllater when we talk of raining clouds. ALL CLOUDS DO NOT RAIN) 13. Rain and cloud We know all clouds do not rain. Normally when rain occurswe will see the clouds are dark and sunlight would become less. The onlyexception is the summer rain- Venal mazha. In simple language let me explain how rainoccurs. Weneed water to live. We get water not only from the under round, but also fromthe clouds in the form of rain. In fact rainwater absorbed deep in to earth surface give us water. The sun gives us heat and light. Due to this heat, thewater in the oceans, seas, and rivers evaporates into water vapour. This watervapour forms as clouds in the sky. This we have seen a little bit detailalready. The clouds do notremain in the same place. They move towardsthe wind direction. (Wind is a separate topic to write) When the clouds are obstructed by mountains or forests, thecool air, changes the water vapour into water. Then we get rain. 13a Water cycle When we get rain, the rainwater collects in the streams,reaches the rivers and finally the river water reaches the oceans. Again the waterevaporates in oceans, rivers, etc, and changes into water vapour and formsclouds. These clouds give us rain. Changing of water into water vapour and water vapour intowater is called `water cycle’. 14. Why white clouds donot make rain? White clouds cannot give us rains. Black cloudscarry more water vapour. So, they give us rain. Crops grow well onlywhen rain falls. If forests are more, there will be enough rainfall. So, to get enough rainfall, weshould grow more trees. And reduce cutting down of trees. 15. Can we feel watervapour? Now it is winter. Almost all theair around us is moist. That means that it contains water in the form ofvapour. We can't see it because water vapour is a gas, but it's still water.Water can exist in three states; liquid (water), solid (ice) and gas (watervapour), we had our chemistry classes in 8th and 9thstandards. My update- Water can exist in some more forms. The above are most commonforms. Obviously, we can see and touchwater and ice, but water vapour has no smell, so we can't pick it up, and it'sinvisible. That doesn't mean that we can't feel it though. We feel it through the chillnessof wind or air surrounding us. Not able to with stand the chillnessof Ootty I found locals burning things and sit near in a TV news two days back. 16. Why clouds rain? Well, warm air can hold more watervapour than cool air as we have seen already and it rises up. If warm air starts to cool after going up, itcan no longer hold as much water vapour. The extra water vapour has to go somewhere, so itcondenses out as water. So...cooling the air reduces it's ability to hold water vapour, and triggers theformation of water droplets. This is the principle of condensation. For a simple understanding, eucalyptus leaves are boiled, vapour risesup, vapour condensed and we get oil with water at bottom. Oil is separatedsince remaining at top. 17. Growing cloud Watch that cloud for a while up in thesky and especially it's edges. As we watch it, the edges will change, eithergrowing larger or getting smaller. What we are seeing is cloud formation inaction. As the cloud grows we are seeing moreof those water droplets condensing out of the air, and as it shrinks, we arewitnessing the droplets evaporating - changing from visible liquid water intoinvisible water vapour. Now,we know that the clouds are usually a long way up, and not every cloud has rainpouring out of it repeated already two times in this article. So, how does theformation of a cloud lead to actual rain? In brief already we read touchingtrees in mountains and forests already by blowing of wind. Interesting? IN NEXT POSTING- Principle of surface tension,different colour of clouds and few more details like rain in deserts, rain insea will be covered. -- You received this message because you are subscribed to the Google Groups "Thatha_Patty" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/thatha_patty/1649797426.2346606.1612618048282%40mail.yahoo.com.
