about history?

Question

First Question:wat does modern and ancient seismograph mean???wat are they different of???can give mi some example and picture of modern and ancient seismograph ???

Second Question:can give mi two achievement that contributed to the proosperity/development of ancient civilization??pls provide mi the two achievement with picture

thx,those who give mi give answer i will choose it as best answer with 5 star

Answer 1

Seismographs are instruments designed to detect and measure vibrations within the earth, and the records they produce are known as seismograms. Like the many other terms beginning with this prefix, these words derive from the Greek seismos, meaning "shock" or "earthquake." Although certain types of seismographs are used for underground surveying, the devices are best known for studying earthquakes.

A seismograph consists of a pendulum mounted on a support base. The pendulum in turn is connected to a recorder, such as an ink pen. When the ground vibrates, the pendulum remains still while the recorder moves, thus creating a record of the earth's movement. A typical seismograph contains 3 pendulums: one to record vertical movement and two to record horizontal movement.

Seismographs evolved from seismoscopes, which can detect the direction of tremors or earthquakes but cannot determine the intensity or the pattern of the vibration. The earliest known device used to detect earthquakes was created by a Chinese scholar, Chang Heng, around A.D. 132. Detailed accounts reveal that it was a beautiful and ingenious apparatus consisting of a richly decorated copper cylinder with eight dragon heads positioned around its upper circumference, facing outwards. Fixed around the lower circumference, directly beneath the dragon heads, were eight copper frogs. In its mouth, each dragon held a small ball that dropped into the mouth of the frog below it when a rod inside the cylinder, flexible and weighted at its upper end, was triggered by an earthquake. The particular frog that captured a fallen ball indicated the general direction of the earthquake


The first electromagnetic seismograph was invented in 1906 by a Russian Prince, Boris Golitsyn, who adapted the principle of electromagnetic induction developed by the English physicist Michael Faraday during the nineteenth century. Faraday's law of induction postulated that changes in magnetic intensity could be used to generate electric currents. Incorporating this precept, Golitsyn built a machine in which tremors cause a coil to move through magnetic fields, thereby producing an electrical current which is fed into a galvanometer, a device that measures and directs the current. The current then fluctuates a mirror similar to the one that directed the light in Milne's apparatus. The advantage of this electronic system is that the recorder can be set up in a convenient place such as a laboratory, while the seismograph itself can be installed in a remote location


Here is a picture of a seismograph

http://regentsprep.org/Regents/earthsci/graphics/seismograph.jpg