When the first dictionary was prepared

The word 'dictionary' had been derived from the Latin word 'dictionarium'. The first English dictionary is said to have been prepared by a school master named Robert Cawdrey in 1604 A.D.

Then in 1721, Nathan Bailey published a dictionary with about 60,000 words and it became the first proper dictionary.

The Oxford English Dictionary we all refer to today was first published in 12 volumes in 1933. It was a work of John Walker. In 1989, it was printed with 20 volumes.

When lasers were introduced

The word laser is short for Light Amplification by Commission of Radiation.The idea of the laser was conceived by scientists during 1950. It grew out of an earlier device-master-used to amplify microwaves.

An American scientist named Theodore H. Maimon developed the first laser in 1960 by flashing ordinary light into a rod of synthetic ruby. Lasers are used today in industry, medicine and communication.

What a shooting star is

Shooting stars are not real stars. They are actually bits of dust from space burning up by friction as they plunge at higher speed into the Earth's atmosphere, 100 Km (62 miles) or so above us.

Their fiery death produces a streak of light in the sky usually lasting no more than a second or so. Half a dozen shooting stars can be seen per hour on a clean night. Astronomers term them as meteors. Several times an year the earth passes through swarms of dust left by comets and the resulting dust storm produces a meteor shower during which dozens of shooting stars may be seen in an hour.

When the first revolving door was made

An American named Theophilus Van Kennel invented the first revolving door in 1888.

He called it the "doorless door" because it was always open, yet always closed.

Today revolving doors are widely used in hotels, restaurants and other large buildings such as housing complexes or offices.