Name any 2 ways which were used for communication in olden days
Answers
Answer:
these are the two ways in which communication used to happen on olden days:-
1)letter
2)telegram.
Answer:
Answer:
Sundials and Obelisks
In 1500 B.C simple sundials were used to divide the time interval between sunrise and sunset in 12 different parts. The Ancient Egyptian Obelisks, constructed about 3500 B.C was the oldest shadow clock used to measure time. The shadows that move to different marks enabled the Egyptians to calculate time which helped to divide day into two parts. It also solicited summer and winter.
Sand-glass
The sand-glass/ hourglass, made up of two conical glass connected vertically by the narrow neck, came into being in the 14th Century. It could measure passage of specific time period depending upon the size and width of the glass and the quantity of sand in it. This tool of measurement was considered more accurate than the water clock or a candle clock.
Water clock
Water clock was known to have existed in Babylon in Egypt around 16th Century. It was used to measure time observing steady flow of water from or into a container. Measurements were marked on the container but there were variations due to the pressure of water flow.
Candle clock
The candle was marked with numbers and the burning of wax indicated a specific period of time. It is unknown where the candle clocks were used although it was first referred by a Chinese poet called You Jiangu in 520 A.D.
Pendulum
A scientific study was done around 1602 by an Italian astronomer Galileo Galilei on pendulum where its motion was used to keep a track of time. It was considered to the the world’s most accurate time-keeping invention until 1930. The pendulum clock was invented by Christian Huygens in the year 1658 which was used till 270 years and was world-wide credited for its accuracy.
The Quartz
In early 20th Century, Albert Einstein proposed theories of relativity and defined time as the fourth dimension. The Quartz clocks were developed in 1930 which were far more improvised version of a pendulum clock. The quartz crystal has to be placed in the suitable circuit in a way that creates interaction between mechanical stress and electric field which creates vibration in the crystal to generate a constant frequency. This is used to operate electronic clock display.
Last, the atomic and laser invention in 1960’s has changed the measurement of time forever. Also, we never know what future the time holds!