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Showing posts from November, 2020


How did one travel earlier?

How did one travel earlier? In the stone ages man shifted from one place to another only when the food at the first location became scarce. Families carried their possessions with them with the help of dogs and other animals. In regions with abundant water simple boats were made for transportation. After the invention of the wheel, new possibilities of transportation came up. Invention of carriages, wagons and later cars made travelling easier and faster. The only requirement was a network of roads.   How did the North American Indians carry their possessions?   The original inhabitants of America frequently lived in the prairies. Since there were no roads in the prairie, vehicles with wheels could not be used easily. In addition, the wheel came to the American continent only with the vehicles of the European settlers. The native Indians used a travois for transportation: a triangle made of two long rods ties at one end and a crossbar at the other end. Over this a piece of leat

What is an atom?

  What is the composition of air? Air cannot be seen, touched, or tasted, but it is much more than nothing. It is a mixture of various gases. Four-fifths of the air is nitrogen gas (N 2 ) and one fifth of it is oxygen gas (O 2 ). Another important component of air is carbon dioxide (CO 2 ). We need oxygen to live and plants need carbon dioxide to live.   What is an atom? The term ‘atom’ comes from Greek word atomos, meaning ‘indivisible’ . Earlier, it was considered that atoms were the smallest units of a substance and could not be split further. Today, we know that atoms can be further split into smaller particles. An atom is made up of the atomic nucleus, which consists of positively charged protons and an equal number of neutrons, and atomic shells. These are occupied by negatively charged electrons, which move at high speeds around the atomic nucleus- like planets around the sun.   What is an element? An element is a ‘pure substance’ consisting of atoms of the same ki

What is photosynthesis?

  Why do plants and animals need to grow? 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. Since plants create their own energy, they are the first link in the food chain. Animals need to drink water and eat plants or other animals to get energy. Therefore, they are present at the nest step in the food chain. There are some animals, like camels, that can survive for days without drinking water. Since they live in deserts with very little water, they have adapted to the special conditions of their habitat.   How do plants get food? Unlike animals, plants produce their own food and except for a few carnivorous plants, do not eat other organisms. Green plants use water, nutrients, and a green matter in their leaves called ‘chlorophyll’ to produce their food. Normally water and nutrients are absorbed from the ground through their roots. S

How do we discover what is inside the Earth?

What is the external structure of Earth? It has been known for more than 2000 years that the Earth is round, but we were able to actually see this much later only when we flew into space. The knowledge why we do not fall off from Earth is much more recent. A journey as describes by author Jules Verne in his book Journey to the center of the earth was, after all, impossible. Only one thing was known: The earth is made up of soil, rocks and water. Today, we know that the Earth is also surrounded by an air cover called the atmosphere.   What is the internal structure of earth? Like an onion, the Earth has several layers. The outermost layer, the Earth’s crust, has an average depth of about 40km. As compared to the diameter of Earth, which is around 12,700 km, the crust is very small. It is primarily made up of solid rocks. Below the crust is the solid mantle, reaching to a depth of about 2900 km. due to the heat inside the Earth, the mental consists of solid and molten rocks. Belo