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How does a Submarine Work?
Jules Verne in his science fiction, 20,000 Leagues under the Sea, mentions a ship, Nautilus, which could dive beneath the waves and surface again when it wanted to. Even before submarines were thought about, Verne had created the blueprint of this technological marvel. Not only did he describe the machine, but he also explained, in great detail, how it worked. In fact, today’s submarines use exactly the same technology as Verne’s Nautilus did! How does a Submarine Work?...
What is a Volcano?
What is nature’s most powerful, most destructive, most dangerous form? Some would say an earthquake, others a cyclone. However, these phenomenon are relatively smaller and less destructive in scale compared to the fury of a volcano. Fourteen miles southeast of Naples in Italy, lie the remains of an ancient town called Pompeii. The city flourished under the shadows of the towering Mount Vesuvius. In 79 AD, the volcano erupted, destroying the cities of Pompeii, Herculaneum, Stabiae and Torre Annunziata....
What is the Weight of Air?
As you stand in the middle of a playground or while you are sitting in your class, there is an immense weight right over your head, but you do not feel it! This is the weight of the atmosphere, or air, as we know it. Composed of nitrogen, oxygen, carbon dioxide and other gases, it surrounds the earth like an envelope. And, it extends almost a thousand kilometres above the Earth’s surface. Like all other substances, air also has weight....
How do Earthquakes Happen?
Simply put, the shaking of the earth caused by a sudden shifting of rocks below its surface, is called an earthquake. The earths crust or outermost layer, is not made of one single piece of solid rock. It is actually made up of independent sheets of rocks called tectonic plates. The tectonic plates of the world were mapped in the second half of the 20th century. These plates slide against each other, giving rise to physical changes in the earths topography....
Why do Airplanes have Wings?
I remember my trip to Goa. The flight was scheduled for six a.m. As the aeroplane taxied on the runway it gained speed. I felt a kick in the stomach and then we were airborne. It was my first flight and I was very excited. My father who was sitting next to me, asked, “Can you tell me how the aircraft flies?” “Because of wings,” I replied promptly. But I could not tell him what the wings do to make a plane fly....
How do Humans Balance on Two Legs?
Four-year-old Rohit couldn’t understand why his parents and grand parents were so happy on seeing his 10-month-old sister, Ruchi, take a few unsteady steps towards her favorite toy. What was so unusual about her walking -after all, he could walk and run without anyone’s help, yet no one ever clapped nor hugged him, the way they were doing it for his sister. Unable to hold his curiosity any longer he decided to talk about it to his closest friend and guide – his mother....
Why does Cola Fizz?
Switch on the television and you are bound to see some cola advertisements. Aamir Khan, a Bollywood hero, pops open a cola and the bubbly drink fizzes to the top. Have you ever wondered what causes the countless teeny bubbles in all these soft drinks? Soft drinks are carbonated, i.e. carbon dioxide gas is dissolved in the liquid. This gas gives the drink its sparkle and tangy taste, and prevents it from spoiling (the gas reduces bacterial growth)....
What is Blood Pressure?
The heart is a live pump that delivers blood to different parts of the body. Blood flows in or flows out when the heart contracts and expands. The blood is forced into the arteries, which expand to receive the oncoming blood. The force with which the blood moves through the arteries is knows as blood pressure. The arteries have a muscular lining which resists this pressure. The blood is thus squeezed out into smaller blood vessels....
Why's it hard for Ketchup to flow?
Why is it so tough to get ketchup out of the bottle? Why’s it hard for Ketchup to flow? [Illustration by Shinod AP] When you overturn a sauce bottle that has been left untouched for some time, chances are, either the sauce will not come out at all or a gigantic blob will plop down on your plate. Getting ketchup to ‘flow’ out of the bottle can be quite an ordeal....
Why do Ears Pop?
Recently I went to the top of a skyscraper in a lift. After I had gone up a few stories, I felt a funny sensation in my ears. My eardrums seemed like they were growing and were about to burst. As I went a little higher, the sensation was worse. My fellow passengers in the lift told me to swallow a few times. This would help the sensation pass, they said. And, it did. This happens to a lot of people when they are flying, or skiing downhill at very high speeds, or going deep into a mine well....
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