210 items in this section. Displaying page 19 of 21
How did the Safety Match Originate?
Fire was invented when two flint stones were struck together igniting a spark. From earliest times people made fire by either striking flint stones or by rubbing a hard stick against a soft one so that the friction caused soft flakes to peel off and start to smoulder. The only improvement on these primitive methods was the tinder box that contained some steel, flint, and some dry tinder for the spark to ignite. This tinder was often pieces of linen or silk....
What is a Tornado?
If you ever happen to see a dark often greenish sky, wall cloud, large hail and a loud roar similar to a freight train then run to a safe place as it could be a tornado. Popularly known as twisters, tornado is derived from Spanish word ‘Tronada’ meaning thunderstorm and ‘Tornar’ meaning to turn. Tornadoes [Illustrations by Amarjeet Malik] A tornado is defined as a violently rotating column of air that can spin faster than 300 m....
The Hows and Whys of Bubble Gum
Chew this question: What is small and pink, tastes sweet, can be chewed for hours without it dissolving, yet is not to be swallowed? Some doctors feel that it helps to relieve stress. Others think it is good for the teeth. Americans are constantly rolling it about in their mouth and the US army gives it as part of field rations. No guesses for the correct answer. Yes, it is chewing gum or bubble gum as it is often called because you can blow large bubbles that go ‘pop’!...
Why do some Rivers Flow Underground
From ancient times, people have settled down along the banks of rivers, since they provide water to drink, to irrigate their fields, and to use as waterways to go from one place to another. But hidden away, below the earth, are rivers that we rarely see, until they surface near the sea, or when they merge with another river. Some have names and are talked of with a sense of mystery, but many are nameless streams that flow through the nooks and crannies of the earth....
What is Asthma?
Asthma is one of the most common diseases affecting the lungs. A serious disease, it affects all races and both sexes equally. This disease affects millions. Many of us recognize asthma symptoms like wheezing, chest tightness and gasping for breath. However, few of us know what is going on inside the body of a person with asthma. When we breathe, we inhale oxygen through the nose and mouth. The air passes down the trachea or windpipe through the two bronchi that branch off into the millions of tiny airways that make up the lungs....
Why do Some People Stutter?
Rahul is a lonely child. He is laughed at because whenever he speaks, he stutters. He goes “my name is Ra-Ra-Rahul.” His mother and grandmother thought it was because he had a short tongue. Other people said it was because, as a baby, Rahul’s hair was cut before he spoke his first word. Finally, Rahul’s mother took him to the doctor. She was told that it had nothing to do with these myths. Rather, Rahul had a speech disorder called dysphemia....
Why are Human Voices Different?
Imagine a scenario. A criminal is being tried in court. He denies saying something. The prosecution brings a recording, saying they have his confession on tape. As the accused vigorously denies the voice being his, an expert shows just why the voice could be no one else’s. A fictional scene? Perhaps, but it is a reality that no two persons in the world have exactly the same voices. Do you know why this is so?...
Where Do Penguins Live?
Short, fat and looking as if they were attending a formal dinner dressed in a tuxedo, penguins could easily be mistaken for people from a distance! Penguins are flightless birds found in the southern hemisphere. No, they are NOT found near the North Pole. Scientists feel that these birds became flightless as food was available in plenty. But their food was located underwater so they adapted to the sea with short flipper-like wings. Where Do Penguins Live?...
What's Biting the Flea?
Scratch, scratch scratch goes your pet dog or cat. Behind the ears, on his body. He whips about trying to chew up his tail. What’s eating him? You part the hair and feel around. It’s a flea! Fleas are parasitic insects that suck the blood of birds and mammals. There are over 2,400 flea species worldwide classified under the order Siphonaptera. They are tiny wingless insects like the lice in our hair, either black or reddish brown....
How Do Fish Survive in Icy Waters?
In cold winter months, lakes and rivers freeze over forming ice. Yet, fish and other aquatic animals manage to survive. Animals like seals, penguins, walruses and a wide variety of sea birds are all fish eaters. They live in the Arctic and Antarctic Circle, amidst the icecaps. The land is completely frozen. Yet these animals manage to live in this region. How do they do it? The icy waters of the Arctic and Antarctic Oceans support a great amount of marine life....