HEAT- POST -11

HEAT post 11

(Convection -part iii)

 Good  Morning  Students, 

We have learnt about convection . During today's blog lesson we will learn about  a few applications  of convectional currents in our day to day lives,. Some of these  you are quite familiar with since they have been introduced to you earlier.

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 Click on the following link to learn about ocean currents:
  https://www.youtube.com/watch?v=EvTZT2ixQKk


EXPLANATION - OCEAN CURRENTS

The ocean water near the equator gets heated by the sun rays.
As a result, the ocean water in the equatorial region becomes hotter and lighter.

The ocean water in the polar region is cold and therefore dense.
Due to its temperature difference , warm water starts flowing on the surface of the ocean from equatorial region to the polar region , the cold water starts flowing from the polar region to the equatorial region below the surface of the ocean .

Such a flow of the ocean water forms ocean currents. Ocean currents help in maintaining the ocean temperature.



For a more detailed explanation, look at the following video:
https://oceanservice.noaa.gov/facts/current.html
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Some questions based on the applicationof convection currents are listed below. Once again try to figure out the answer yourself before checking the answer:-

DO THE QUESTIONS IN GREEN IN YOUR NOTEBOOK



Q 28)   Why are air conditioners fitted at a higher level on the wall of the room?

Ans) Cold air is heavier than warm air. The cool air from the cooler or air-conditioner being heavier moves downwards, whereas the hot air at the lower level moves upwards and gets cooled and comes down once again. Thus the convection current are set in the air and room gets cooled faster.

 



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Q 29)    Why are room heaters placed at or near the floor?
Ans) Air heated by the heater is warm and rises. Cooler air being heavy moves downwards and gets heated and thus becomes lighter and rises up. Till the time the cold air is heated the warm air at the top becomes cold and moves downwards. This cycle of convection current keeps repeating and the room gets warmer more faster.



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  Q 30)    Why is freezer mostly located at the top in a refrigerator?

Ans) The air around the freezer compartment gets cooled and moves downward. Warm air being lighter moves up to be cooled and then again the cold air becomes warm and rises. The convection currents are set in the refrigerator and the lower section of the refrigerator also gets cooled up faster.




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 CW.   Question and Answers - Text in  GREEN  to be written out.

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