Miscellaneous

The Mohs Hardness Scale is used as a convenient way to help identify minerals. A mineral's hardness is a measure of its relative resistance to scratching, measured by scratching the mineral against another substance of known hardness on the Mohs Hardness Scale.

A Fathometer is used to measure the depth of the ocean. The relative density of liquids is determined with a hydrometer.

The instrument used to measure rainfall is called a hyetometer. The instrument used to measure the humidity in the atmosphere is called a hygrometer. The instrument used to measure the relative density of milk is called a galactometer.

An aquifer is the area beneath the surface of the Earth that has porous rocks which bear water. These aquifers are a source of potable water which can be easily accessed using water wells or pumps.

Bhaskaracharya was the first Indian astronomer to calculate the time taken by the earth to orbit the sun. He was born in Bijapur, Karnataka.

Sandford Fleming, a Canadian engineer, invented the Universal Standard Time. Sir Sandford Fleming advocated the adoption of a standard time or mean time, as well as hourly variations from that according to established time zones.

In 1855 Italian scientist Luigi Palmieri designed a seismograph that consisted of several U-shaped tubes filled with mercury and oriented toward the different points of the compass.

Millions of years ago, the Indian subcontinent was separated from the mainland by a large sea known as the Tethys. During the movement of the earth's crust, known as Continental Drift, it began moving northwards towards the mainland.

The Chandrasekhar Limit of 14 solar masses is the theoretical maximum mass a white dwarf star can have and still remain a white dwarf (though this limit does vary slightly depending on the metallicity).

The plate movements on Earth are classified into three types, which are: Divergent boundaries: In this type of boundary, the

plates move away from each other. This type of movement leads to the formation of rift valleys, mid- ocean ridges, and new crust formation. Convergent boundaries: In this type of boundary, the plates move towards each other. This type of move- ment leads to the formation of mountains, subduction zones, and volcanic activity.

Transform boundaries: In this type of boundary, the plates move past each other in opposite directions. This type of movement leads to the formation of faults and earthquakes.