Sep 20, 20212 minHow was the ball point pen invented?The first model of a ballpoint pen was patented in 1888 by an American, John H. Loud, for writing on rough surfaces. But a successful...
Sep 20, 20212 minWhere was zero invented?The inconsequential number zero was a major invention which has had a tremendous impact on the history of mankind because it made the...
Sep 20, 20212 minWhat is heavy water?We know that ordinary water is a compound of hydrogen and oxygen. It has two atoms of hydrogen and one atom of oxygen and is represented...
Sep 20, 20212 minWhat is an atomic clock?Since long, man has used clocks and watches to measure time. But those were crude watches and did not measure time accurately. A few...
Sep 20, 20212 minHow do astronauts walk in space?It appears strange but true that astronauts can walk in the space. This is so because in ordinary walking, we rest our feet on the...
Sep 20, 20212 minHow do ice columns grow inside caves?Ice columns appear in many caves or caverns. They are called stalactites and stalagmites. Stalactites are the stony deposits hanging like...
Sep 20, 20212 minWhy does the Mediterranean Sea appear blue and the Atlantic Ocean green?Do you know that about three-fourths of the Earth’s surface is covered with water? There are three main oceans — the Atlantic, the...
Sep 20, 20212 minHow do we find direction in the sea?In the beginning, when man made boats, he also used them for the sea voyages. But he did not dare to travel too far because of the fear...
Sep 20, 20212 minHow is weather forecast made?Weather is the day to day change in the state of the Earth’s atmosphere. Every day, we get weather forecast through newspaper, radio and...
Sep 20, 20214 minWhat causes tides in the sea?The giant water waves which rise and fall periodically in the sea are called tides. Sometimes these tides are so high that they appear...
Sep 20, 20211 minAre there mountains inside the sea?Generally, sea mountains are those mountains which are at least 1 kilometre above the seabed. A number of such mountains have been...
Sep 20, 20211 minWhat is Dead Sea?Dead Sea is the only sea on Earth which has no plant or animal life. It is, therefore, appropriately called Dead Sea. In fact, Dead Sea...
Sep 20, 20211 minHow were the oceans formed?About three-fourth of the Earth’s total surface is covered with water; only one-fourth is land. The total area of the Earth’s surface...
Sep 20, 20212 minWhat causes asthma?Asthma is a chronic disease of the lungs in which a person has sudden attacks of shortness of breath, wheezing and coughing. It is one of...
Sep 20, 20212 minWhy do doctors examine the pulse?When a person falls sick, the doctor often examines his pulse by placing his fingers on the wrist of the patient. What does this pulse...
Sep 20, 20212 minWhat is a test-tube baby?Human life continues through the process of sexual reproduction. This involves the fertilisation of a female egg cell with a male sperm...
Sep 20, 20212 minWhy do dogs pant in summers?A dog, like a cow, an elephant, or man, is a mammal. All mammals are warm-blooded, or homothermic animals. In the animal world, only...
Sep 20, 20212 minWhy do flowers ofraat ki rani bloom only at night?Many animals and creatures rest during the day but become active at night. Similarly there are many plants which bloom at night only....
Sep 20, 20212 minWhy do flies rub their legs together?Fly is a two-winged insect that has some 90,000 different species of it. The housefly (musca domestica) is one of the most common of all...
Sep 20, 20211 minWhy don’t leaves get heated in sunlight?Anything exposed to the sunlight for some time becomes very hot, especially during the summer months. A scrap of paper or a piece of...