Science magazine for children: Packed with science stories, science facts, science features, and other science learning resources for children. Discover the known, the unknown, and little-known facts in our science articles. Learn the how and why of everyday things and explore rare and exotic living species.
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How Does Satellite TV Work?
Nine ‘o’ clock. It’s time for your favourite serial on television. Have you ever wondered how the same serial can be viewed by millions of people across the world? This is possible because of satellite television technology. It uses man-made or artificial satellites to send your favourite serial to your television set. But why do we need satellites for this purpose? How Does Satellite TV Work? The earth is round To understand this, we have to first take a look at the shape of our earth....
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 Wool Came Into Existence
It must have been a very intelligent human who looked at a sheep walking past and thought of the use its fleece might have! Although the oldest surviving textile made out of wool is around 3,500 years old, the oldest fine woolen fabric dates to the fifth century BC (about 2,500 years ago) and was found in an ancient Greek colony. How Wool Came Into Existence Wool was probably the first fiber to be woven into a textile....
Why do Doctors Examine the Pulse?
If you place the first three fingers of your hand on the inside of your wrist, a dull throbbing reverberates through your hand. Da-dub, da-dub, da-dub. Very reassuring, these gentle thuds, that remind us that our bodies are kicking along, and that, at least at last touch, we’re alive and well. By pulse we mean the regular throbbing of arteries caused by the successive contractions of the heart. During the action of the heart there is a pause....
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....
How are Earthquakes Recorded?
When an earthquake takes place, people say that it measured 6.2 or 6.5 on the scale. The scale they are referring to is the Richter Scale developed by Charles Richter in the 1930s. The Richter Scale measures the magnitude of the seismic waves or vibrations that travels across the earth’s surface. The scale uses a logarithmic formula using high-frequency data collected from seismograph stations. However, long before Richter developed his scale, a Chinese philosopher Chang Heng invented a device to measure earthquakes in 132 A....
Who invented Hello?
Hello, Hullo, Hallo, Hull-oo-oo-oo. You may say it softly or you may holler at the top of your voice, but the person at the other end knows that all you are trying to do is get in touch with a greeting. Legend has it that Thomas Alva Edison was the first to say hello over the telephone. But Edison didn’t invent ‘hello’ by a long shot. As a matter of fact, the greeting has been around for centuries much before the invention of telephone in 1885....
An Organism that is visible from Space
The elephant is the largest land animal. The Blue whale is the largest sea animal. But however big these animals may be, they can not size up to the colonies built by tiny little sea creatures – the coral. The colonies built by corals are called coral reefs. Coral reefs can be as huge as big islands or even as big as a country! These reef-building corals are not single animals. A coral is a colony made up of many individual animals called polyps....
Why was the Berlin Wall Built?
A few tentative steps across Checkpoint Charlie and you were transported to a different world. One side had McDonalds, Coke, Toyota cars and a democratically elected government. Across the Checkpoint, was a world of state-owned factories, rows and rows of identical apartments, and a self-imposed government. This was the world of the two Berlins divided by barbed wire, watch dogs, tanks, and an imposing wall. In 1945, following World War II, Germany was divided into two countries – East Germany and West Germany....
How do Satellites Stay Up?
Satellites orbit the earth because of the force of gravity. To understand why this happens and why the satellite does not get pulled in and fall, we have to understand what forces do. A force will change the motion of an object; it might speed it up, slow it down or change its direction. For example, if you are running and someone pushes you from behind, you speed up (the force is in the direction of your motion)....