There is no written evidence which can tell us exactly who has coined the phrase educational technology. Different educationists, scientists and philosophers at different time intervals have put forwarded different definitions of Educational Technology.
The second stage of educational technology is associated with the ‘electronic revolution’ with the introduction and establishment of sophisticated hardware and software. Use of various audio-visual aids like projector, magic lanterns, tape-recorder, radio and television brought a revolutionary change in the educational scenario.
The fourth stage of educational technology is discernible by the individualized process of instruction. The invention of programmed learning and programmed instruction provided a new dimension to educational technology. A system of self-learning based on self-instructional materials and teaching machines emerged.
The latest concept of educational technology is influenced by the concept of system engineering or system approach which focuses on language laboratories, teaching machines, programmed instruction, multimedia technologies and the use of the computer in instruction. According to it, educational technology is a systematic way of designing, carrying out and evaluating the total process of teaching and learning in terms of specific objectives based on research.
Duringthe Stone Age, ignition of fire by rubbing stones, manufacture of various handmade weapon and utensils from stones and clothing practice were some of the simple technological developments of utmost importance.
Although Stone Age cultures left no written records, but archaeological evidences proved their shift from nomadic life to agricultural settlement. Ancient tools conserved in different museums, cave paintings like Altamira Cave in Spain, and other prehistoric art, such as the Venus of Willendorf, Mother Goddess from Laussel, France etc. are some of the evidences in favour of their cultures.
Neolithic Revolution of Stone Age resulted into the appearance of Bronze Age with development of agriculture, animal domestication, and the adoption of permanent settlements. For these practices Bronze Age people further developed metal smelting, with copper and later bronze, an alloy of tin and copper, being the materials of their choice.
The Iron Age people replaced bronze and developed the knowledge of iron smelting technology to lower the cost of living since iron utensils were stronger and cheaper than bronze equivalents. In many Eurasian cultures, the Iron Age was the last period before the development of written scripts.