Category Science

Sandip Trivedi

Sandip Trivedi  is an Indian theoretical physicist working at Tata Institute for Fundamental Research (TIFR) at Mumbai, India, while he is its current Director. He is well known for his contributions to string theory, in particular finding (along with Renata Kallosh, Andrei Linde, and Shamit Kachru) the first models of accelerated expansion of the universe in low energy supersymmetric string. His research areas include string theory, cosmology and particle physics. He is now member of program advisory board of International Center for Theoretical Sciences (ICTS). He is also the recipient of the Infosys Prize 2010 in the category of Physical Sciences.

Fields

  • Theoretical physics

Institutions

  • Indian  Institute of Technology Kanpur
  • California Institute of Technology
  • Institute for Advanced Study
  • TIFR

Notable awards

  • Shanti Swarup Bhatnagar Award
  • Infosys Prize
  • TWAS Prize

To read more about Sandip Trivedi Click https://en.wikipedia.org/wiki/Sandip_Trivedi 

Why can’t animals talk like us?

            In many stories it is told that animals can talk like us. But this is our imagination only. Amongst all the living beings, man is the only creature on earth who can communicate with the help of words or speech. This is because of the higher development of our brain. Because of a less developed brain, animals have not been able to originate words or a language to express their feelings. Hence they can’t talk like we do.

            It is a well-established fact that the animals too feel happiness, sorrow, fear, love, affection, hostility, hunger, thirst or protective needs etc. as humans do. Because they are incapable of expressing their feelings in words, they express or communicate to each other or to humans, with the help of certain gestures and sounds, which may or may not be familiar or understood by us. You might have seen when a cat goes near a group of birds, all the birds start chirping very loudly in a peculiar way. They actually express their fear that they may be caught by the cat. Similarly a dog expresses its anger by barking and its feelings of flattery by wagging its tail. A monkey demonstrates its anger by making peculiar sounds.

 

How is bark formed?

              Bark is the protective outer covering of tree branches, trunks and roots. Bark has three layers. The outer layer called periderm is made of dead cells, such as cork. Periderm is usually thick. It protects the tree against weather, insects and diseases. The middle cortex layer is made of living, non growing cells. The innermost phloem brings food made in the leaves, down to the roots. The periderm of some trees has small openings called lenticels. Lenticels allow gases such as oxygen and carbon dioxide to enter and leave the plant.

             As wood is laid down inside a shoot, a layer of cells near the outer side begins to divide and produce cork cells. The walls of these cells soon get heavily thickened with a waterproof substance. The cells die and form bark.

           Over the years the bark is constantly added to form the inside of the tree. So as the diameter of the twig, branch or trunk increases, the waterproof barrier is maintained. But the outer bark often splits and cracks or becomes flaky.

           As already mentioned, the bark protects a tree from the weather and sudden temperature changes. It contains substances that repel insects and resist fire. Bark often has commercial uses. The actual cork comes from the bark of the Mediterranean cork oak. The drug Quinine is obtained from the bark of Cinchona trees and Cinnamon comes from the bark of the Cinnamon tree. Cough medicines and many other useful substances are also obtained from the bark.  

 

How do plants take and make their food?

            It is a well-known fact that trees and plants are also living beings like humans. They need food, water and air for survival. It is interesting to know how they take their food.

            Plants derive their food both from the earth and the air. If you minutely look at their roots, you will find that the ends of these roots are like fine fibres. We call them root-hairs. They absorb water and minerals and transport them upwards to the leaves through the trunk and the branches. It is the leaves which prepare the food.

            The leaves have pores which are filled with air. They also have a green colouring matter called chlorophyll. This chlorophyll acts as a catalyst, and uses carbon of the carbon dioxide and the hydrogen of the water present in the leaves to make carbohydrates (sugars). In this process oxygen and water are given out which are excreted by the leaves of plants.

            Sugar is further converted into starch. From these carbohydrates, the plant can build up complex substances as foods which it needs for its life and growth. These substances include proteins, juices, oils (fats) etc. The water from which the plants take hydrogen for photosynthesis contains dissolved minerals needed in building various parts of the plant body. These are chiefly the compounds of nitrogen, sulphur, phosphorous, sodium, calcium, magnesium, iron etc.

            Food not immediately needed for growth is stored in the plant including its seeds, fruits, tubers or bulbs. This accumulated food in the seed is used in its germination.

 

How do animals and pants survive in deserts?

            Due to the scarcity of water and particular climatic conditions (hot, dry, windy) prevailing in the desert, it is very difficult for animals as well as plants to survive. Nonetheless, we do find some of these. These are adapted to the desert conditions. Let us see what types of vegetation and animals are found there and how do they survive.

           The vegetation of a desert is mainly thorny shrubs, cacti and palm (especially date) trees. Cacti and other desert plants have adapted themselves to live in desert conditions. They have evolved ways to store water in their fleshy stems. The leaves have squeezed themselves into tiny thorns to reduce the loss of water. The roots go deep into the ground and are wide spread to collect every drop of water available. The stem stores the water and slowly gets thinner as the water gets used up. In some cacti the thorns are pointed towards the earth. The dew drops deposited on the ends fall on the earth hence moisture is maintained below the cacti. There are quite a few animals found in deserts such as snails, pack rat, jerboa, etc. Most desert animals sleep during the day to escape the day temperature and they come out in night in search of food. Some animals sleep during the hottest part of the year. Animals such as kangaroo, rat and gerbil can survive with little or no water. Reptiles adjust their body temperatures to cope with heat and cold. The Australian desert toad stores water in its body. Some lizards, ants, owls and snakes also live in deserts. 

 

How do some creatures make a shell on their body?

             You must have heard the sound of conch (shankh) blowing in the temples. You must have also seen big and small conches at sea-shores and on the river banks. Some conches are so small that they can be seen only with the help of a magnifying lens, whereas there are others as big as measuring up to 120 cm.

              Do you know what these conches are and how they are formed? They are the body shells of aquatic creatures. These creatures are called mollusks. Some 60,000 species of the mollusks have so far been studied by the scientists. As the size of the mollusk increases, the outer shell also increases and becomes harder. They are made up of calcium carbonate (lime). The mollusk collects lime from the sea water and deposits it in its outer shell. When the mollusk dies, the shell floats and comes to the surface of water.

              The shell of the mollusk has three main layers. The outer layer of the shell is made up of smooth material like the oyster and contains absolutely no lime. The layer below this i.e. the second layer is made up of calcium carbonate. The lowest layer that is the third layer is a group of many thin layers, which are made up of oyster-like material and calcium carbonate. The conches are of many colours. They have many stains and stripes. These stains, colours and stripes have their origin in some colourful materials present in the glands of the mollusk. These colours, stripes and stains enhance the beauty of the conches.

              The conches not only protect the mollusk, but they are also very useful for us. In ancient times people used mollusk shells as coins. Small conches are even used as part of necklaces. They are used as decoration pieces in homes. Buttons are made from small shells. Aquatic animals with shells have been existing for billions of years. After their death these shells deposit themselves on the sea-bed which forms rocks of limestone.