My Science School

Charles Darwin was an English naturalist who is best known for his ideas on evolution. In 1831, Darwin set sail on the HMS Beagle, a naval survey ship. Darwin’s job was to collect plant and animal specimens from the countries the ship visited. The voyage took five years.

      For Charles Darwin, the most important part of the journey was the time spent in the Galapagos Islands which are the home to plants and animals that can’t be found anywhere else in the world.

      On his return to England, Darwin stated to piece together his theory of natural selection which explains how populations evolve. In 1859, Charles Darwin published his book ‘On the Origin of Species’.

     According to this theory, all species of life have evolved over time from common ancestors. Charles Darwin changed the way humans viewed themselves.

Jean Louis Agassiz, a Swiss-American naturalist, was an outstanding comparative anatomist. When he was only 21 years old, he published the work that launched him on his long and distinguished scientific career. It was titled ‘The Fishes of Brazil’ and it was the most important account of a local fish fauna published till that time.

       Later, Agassiz worked under Georges Cuvier, another brilliant comparative anatomist. Agassiz made extensive contributions to ichthyological classification, including of extinct species.

      Ichthyology is the branch of biology devoted to the study of fish. Agassiz also played an important role in the study of geological history including the founding of glaciology. He was a person with many interests- a biologist, physician, geologist, teacher, and most importantly, a prominent innovator in the field of the study of natural sciences.

John Dalton, a British scientist, is probably best known for his groundbreaking research and contributions to two completely different fields- atomic theory and colorblindness.

It was discovered in 1995 that Dalton actually had a very rare form of color blindness- he was only able to see one colour, yellow.

So, he studied the problem in great detail and concluded that colorblindness was a genetic feature, as his brother was also colour blind.

Dalton was also very influential in the study of meteorology, specifically barometric pressure. This led to his publication of a series of papers called experimental essays in which he discussed the makeup of mixed gases.

The most important of all Dalton’s investigations are those concerned with the atomic theory in chemistry. The research had a great impact on atomic theory. He created a listing of atomic weights for six different elements – hydrogen, oxygen, nitrogen, carbon, sulfur, and phosphorous.

Dalton’s interpretation of atomic theory maintained that atoms are combined in chemical reactions, but also that they can be separated and rearranged. Without doubt, it was John Dalton’s atomic theory that laid the foundations of modern chemistry.

Below a certain depth all the porous spaces are saturated with water. This upper limit of the ground water is called the water table.

Water cycle or hydrological cycle is the natural evaluations of water through biosphere. Water is lost from earth’s surface to the atmosphere by evaporation from rivers, oceans, and seas etc. This atmospheric water forms clouds and creates rainfall. The water that collects on land, again flows to oceans, seas and rivers etc., and completes the cycle. 

Rain, snow, rivers, streams, brooks, lakes, ponds, wells, springs, underground water, ice sheets, etc. are the main sources of water. 

Pure water is colourless, odourless and tasteless. It can exist as solid (ice), liquid (water) and gas (steam). Water freezes at 0°C or 32° F and boils at 100°C or 212°F. It is a peculiar liquid in that it expands when it freezes. That is why ice floats on water. 

Water makes up 60-70% of the human body or about 40 liters of which 25 are inside the cells, 15 outside. People can't survive normally more than five or six days without water or two or three days in a hot environment. 

To scientists, water is a compound of hydrogen and oxygen. One molecule of water contains two atoms of hydrogen and one atom of oxygen. There is about 1.4 billion Cubic kilometer of water on the earth which covers about 71% of the earth's surface. About 97% of the water on the earth is in the oceans. 

Friedrich Wohler was a German chemist who chose to be a teacher of chemistry. He was one of the finest scientists of the 19th century.

        Wohler gained international renown from two path breaking discoveries. In 1827, Wohler prepared the first pure sample of aluminum. This metal is the third most prevalent element in the earth’s crust, but it is exceedingly difficult to isolate it from its compounds.

        He also discovered how to make urea in the laboratory without the use of a living kidney. This was an important discovery, because it heralded the end of an existing theory that organic compounds could only be made by living things. Wohler was the co-discoverer of beryllium, silicon, and silicon nitride.

       In 1832, Wohler, along with another scientist Justus Liebig published a study on the oil of bitter almonds which proved that a group of atoms can act like a single element, and be exchanged for elements in chemical compounds. This too, took the scientific world by storm.

Michael Faraday was 19th century British chemist and physicist. He is often called the father of electricity with good reason.

       His work on electrochemistry and electromagnetism laid the foundation for many areas of science. It was in 1831 that Faraday discovered electromagnetic induction, the principle behind the electric transformer and generator. This discovery was crucial in allowing electricity to be transformed from a curiosity, into a powerful new technology. He was partly responsible for coining many familiar words including ‘electrode’, ‘cathode’ and ‘ion’ Faraday laid the basis of the electromagnetic field concept in physics, discovered the laws of electrolysis, and invented electromagnetic rotary devices that were vital in the creation of electric motors. Faraday has thus played a key role in the development of electricity for use in, modern technology.

Sir Humphrey Davy was an English chemist who made many notable contributions to science, especially in electrochemistry. He is renowned for the invention, in 1815, of the Davy safety lamp that helped to prevent explosions in coal mines. Davy was the first to isolate several chemical elements, including sodium and potassium.

        He discovered boron, and found that nitrous oxide, or laughing gas, had anaesthetic properties that could be useful in surgery. Davy did many experiments on the effect of breathing in certain gases- and once, almost killed himself by inhaling a mixture of toxic gases.

      His research included work on early forms of electric batteries, and the use of electricity to isolate chemical elements. He also analyzed mineral, and completed many studies in tanning and agriculture chemistry.

    Did you know that in 1809, Humphrey Davy invented the very first electric light? He did this by connecting two wires to a single battery, and then attaching a charcoal strip between the other two ends of the wires. The charged carbon then glowed, making the very first arc lamp. Humphrey Davy was one of the greatest scientists, ever in the history of mankind.

Amedo Avogadro was an outstanding Italian physicist who lived in the 18th century.

    Although he had followed the family tradition by studying law, he gradually lost interest in legal matters. He found science was much more intellectually stimulating.

    Mathematics, and physics, in particular attracted his logical mind. Avogadro is chiefly remembered for his molecular hypothesis, first presented in 1811. He stated that equal volumes of different gases contain an equal number of molecules, provided they are at the same temperature and pressure.

     Amedeo Avogadro was a great scientist who made important contributions to physics. However, he never received any awards for his discoveries.

      Avogadro’s hypothesis gained acceptance only after his death as people did not recognize their significance. In honour of his contribution to molecular theory, the number of molecules in one mole was named Avogadro’s number.

Andre-Marie Ampere was a French physicist and mathematician, who made the revolutionary discovery that a wire carrying electric current, can attract or repel another wire next to it, that’s also carrying electric current. The attraction is magnetic, but no magnets are necessary for the effect to be seen.

      Ampere went on to formulate Ampere’s law of electromagnetism and produced the best definition of electric current of his time. He also proposed the existence of a particle we now recognize as the electron, discovered the chemical element fluorine, and grouped elements by their properties.

     In recognition of Ampere’s contribution to modern electrical science, the ‘ampere’ was established as a standard unit of electrical measurement, in 1881, forty-five years after his death