Knowledge Shop

    Today, scientists are aware of around 320,000-500,000 different species of plants, but they estimate this number to be much higher. Many of the known trees and flowers come from Asia, while other species of plants thrive in the tropical rain forests. Some plants have adapted to live in or below water, whereas some have adapted to live in the desert areas. Algae, lichen, and moss also belong to the plant kingdom. Lichen:     Many lichens grow in inhospitable terrain; for instance, in the rocky highlands and cold Arctic. They also grow on the walls of the houses in big cities. The growth rate of lichens very slow -a few species grow less than one millimetre in a year. If you step on them, you may destroy in seconds a plant that took hundreds of years to grow. Since lichens are very sensitive to air pollution, they are often used as pollution indicators. The cleaner the air the more lichen will grow.                ...

Diversity of Species:      Deer, bears, salmons, pelicans, elephants, oaks, cacti, algae, lichens -any list illustrating the huge diversity of species on the Earth is inevitably and unending one. Many animals and plants inhabit our gardens; others live on high mountains or in colourful shimmering coral reefs. All of them have adapted to their environment in order to survive. This is all the more true in the case of animals that live in deserts or in extremely cold regions. Unfortunately, we are increasingly destroying the habitats of animals. We are clearing forests and polluting seas and coastal areas.  What do plants live on?     We know very well what animals eat. But what do plants do to live? almost all plants and animals need air, water, light, and nutrition to grow. Green plants use a complicated chemical process, called photosynthesis, to create energy for survival and growth. In this process the chloroplast inside the green leaves o...

   Since the animals have evolved species continue to become extinct. The most well-known example of extinct species is that of the dinosaurs. Often the species cannot adjust fast enough to the changing environmental conditions, or new species arise and displace the existing ones. Today, many species are becoming extinct because of the actions of humans. Elephants, big cats, and rhinos are hunted ruthlessly, forest areas are cleared, and the grey whales are endangered. These are only a few of the species mentioned in the ' Red List'. Do you know about 'Red List'?     'Red List' comes under organization IUCN (The International Union for Conservation of Nature). The list of endangered species is known as the Red List. It lists all those plant and animal species that  are facing the threat of extinction worldwide. The list is revised every 2 years. For the year 2006, the list contained around 16,000 species of plants and animals; 530 species more than t...

   We to live close to nature; animals, plants, soil, and water are all important for our well-being. Despite this, we keep destroying the gifts of nature with pesticides, garbage, and even through tourism. We must seek ways to protect nature. For example, we should adopt use alternative eco-friendly forms of energy. Each one of us can contribute towards saving the environment by avoiding food grown with the help of pesticides and choosing a fuel-efficient means of transport. All countries must come together to save the climate of the world. The Kyoto Protocol is a major step in this direction.      The Kyoto Protocol is an international agreement aimed at fighting global warming . The countries that have signed the protocol have committed themselves to reduce the emission of greenhouse gases step by step, and thus prevent air pollution and global warming. The name of the contract come from the Japanese city of Kyoto, where this agreement was signed in 199...

Asteroids👈 Asteroids are small heavenly bodies, which move around the sun like the planets. Thus, they are also called planetoids. Most of them go around the sun in the asteroid belt. The asteroid belt is the space between the orbits of Mars and Jupiter. In this area, billions of small rocky heavenly objects revolve around the sun, which are known as asteroids. The belt stretches only a few kilometres across. The asteroids originated probably at the same time as the planets. Possibly they are the remains of an 'unsuccessful attempt' to build a planet. Since they are very small, the asteroids can be thrown out of their orbit by a small collision. They can then fall on Mars or on the Earth. Comets👈 Comets, like Halley's comet, which has been sighted many times in the sky, are small heavenly bodies. They are characterized by a different orbit and a bright glowing tail. Halley's comet mostly shines brightly and can be seen with the naked eyes when it is very...

The brain is made up of two halves. Different areas of the brain have different functions. All nerve cells in the brain, about 100 billion of them, are connected to one another and transmit information. This network of the nerve cells is expanded through learning and training. Our brain controls our actions, regulates our sleep, and allows us to feel sensations like pain and joy. If it is damaged, maybe due to a stroke, one has to relearn a lot of things like speaking, walking, or eating. How do nerve cells transmit signals? Signals transmission through nerve cells is quite complicated. Like all the other cells, nerve cells also have a cell body with a nucleus. There are fine extended branches known as dendrites and a long 'tail' called the axon on the body of the nerve cells. Axons in the brain are smaller than 1 mm, whereas in the spinal cord they can be as long as 1 m. A chemical substance is released through an electrical impulse into the synapses present at the end...

Earlier outer space was the stuff of science fiction novels -today, about 800 artificial satellites are orbiting in space. These are specially designed flying machines, which encircle the Earth or the moon in fixed orbits. Numerous scientific probes were sent into space by various countries, and, since its establishment, the ISS has continued to enrich our knowledge of the endless universe and to open up possibilities of putting it to use. But our increasing activities in space have given rise to a new and serious problem: the accumulation of space debris. How are satellites launched?     Satellites are transported to space by carrier rockets. During the launch, the satellites mostly have a covering of metal, which protects them against wind, light, dust, air pressure, and the heat resulting from the friction they experience while passing at high speed through the atmosphere. This cover is discarded later on during the journey. During a satellite launch, the thrust of ...

Do we really know about a star?     Stars are heavenly bodies, which shine like our sun. Many shine brightly, the others have a dim glow. Some are red while others are blue. Stars are giant balls of gas made of hydrogen, bound together by their own force of gravity. The energy that makes them shine comes from a kind of power plant in their interior, where atomic nuclei of hydrogen atoms are fused together to form helium atoms. The stars do not live forever and ;die' at some point. Many simply get extinguished, while very heavy stars expand and explode. Their remains become either a neutron star of a 'black hole'.     The cradle of a star is a cloud of hydrogen and dust. There are numerous such clouds in the universe. By the action of external forces -such as the explosion of a star -this cloud gets compressed and keeps pulling itself together due to the increasing force of attraction among the particles. After a few hundreds of thousands of years, it begins to ...

Do we know?. why does the moon changes its shape? The moon, which causes high and low tides on the Earth, is a sphere. It does not changes its shape; only our view of it changes. The reason is that unlike the stars, the moon does not produce light, but only reflects the light of the sun. Since the moon goes around the Earth once in a month, the orientation of the moon, the sun, and the Earth respective to one another changes. For this reason, the illuminated part of the moon cannot always be seen clearly from the Earth. Sometimes we see it full, sometimes half, and sometimes not at all. The side of the moon that faces us remains the same. We can see the craters and dark spots on the moon, which are known as 'mares'. We always see the same side of the moon. It happens because of the moon rotates once on its axis during the time it complete one revolution around the Earth -which is 27 days, 7 hours, and 43 minutes. The mutual attraction between the Earth and the moon ha...

How can we classify the history of the Earth?   Like the history of human civilization, the history of the Earth too is divided into periods. However, these periods cover not just a few centuries, but millions of years. Broadly, we differentiate between the time preceding the period 550 million years ago and the time after that, during which life developed very quickly on the Earth. Researchers have gathered a lot of data regarding the different periods of the Earth's history by studying fossils. Thus, we came to know at what time fishes and birds appeared on the Earth, why plants and animals lived in the sea for so long, and what the different types of dinosaurs ate. After the 'Archeozoic' period of the Precambian era, which lasted till about 550 million years ago, came the Paleozoic era. This era is subdivided into Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian periods. In the Cambrian period, different types of organism lived in the sea. ...