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Why does water stay cool in earthen clay pots?
Have you ever had a drink of cool refreshing water from a ‘matka’ or earthen clay pot placed outside? Surprisingly enough, the pots are exposed to blazing sunlight, yet the water within stays so cool. How is that possible? This is because of a physical process known as evaporation. When a liquid changes to a gaseous (or vapour) state without boiling, it is known as evaporation. A matka is made of mud and has many minute pores (extremely small holes)....
How Does Dew Form?
Remember walking to the school or the bus stop on a cold wintry morning? You can see the beautiful crystal drops of dew, and if you happen to be on the grass, they could well be soaking your shoes. Ever wondered why there is no dew in the summer or rainy seasons? Well, special as it looks, dew needs special conditions to form as well. When a warm and clear day is followed by a cool evening and night, which is clear (cloudless), dew is formed....
Why does Milk spill over when it Boils?
How many times have you seen milk boil and spill over, and wondered why this happens? To answer this question we have to know a little more about the composition of milk. Milk and its composition Unlike water, milk is not a simple liquid. It is a colloid and contains many substances in suspended form. These substances are mainly protein, sugar and fat. When milk is heated slowly, the proteins and fat get separated. Since they are lighter than the milk they collect on the surface in the form of a layer called cream....
What is the Trail behind a Jet?
When we were small, we used to look up to the sky and often see a white trail left by a jet aircraft. Rocket! Rocket! We used to yell, jump up with joy, clap our hands and strain our eyes as the ‘rocket’ disappeared into the horizon. Soon, the white streak would change into a broken, twisted cloud path. And we were told that it was the fairies’ trail. What is the Trail behind a Jet?...
When will the Oceans of the Earth Overflow?
Try this out. Plug the sink and leave the water running. It will lead to a flood in the bathroom and a scolding for letting the water overflow. Since the sink could not hold an unlimited amount of water, it let the water spill out. But even the oceans are enormous bodies of water that get flooded with water from rain, melting ice, and rivers year after year. Will they start overflowing too? If so, when?...
What are Dry Clouds?
It is that time of the year when all of us look to the sky, waiting for the first drops of rain to fall on our faces. We wish the monsoon would come soon. But for people who live in polluted cities like Delhi or Tokyo, there’s some bad news. Israeli scientists have discovered that air pollution may actually stop rain from falling. To know how pollution may prevent rain from falling, it is necessary to know how and when rain falls....
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