The twilight hours were the hours before dawn and after sunset. After a while, the Egyptians and other ancient societies realized that the sun rose and set in different places in the summer and winter. In fact, the sun never took the same course on any one day throughout the year and also if the sky is overcast throughout the whole day and night this method would not work. (Barnett, 1998)
The major fault with sundials and shadow clocks is obvious so, around 1400 B.C. water clocks were invented named clepsydra. A water clock was made of two containers of water, one higher than the other. Water traveled from the higher container to the lower container through a tube connecting the containers. The containers had marks showing the water level, and the marks told the time.
Water clocks worked better than sundials because they told the time at night as well as during the day. But it also had its own limitations like Water would flow more slowly or quickly when the temperature changed.
The first mechanical clocks appeared in Europe, supposedly because of inspiration by the stories that came from China about mechanical clocks. The first mechanical clocks were rather simple and just sounded a bell every hour. The first mechanical clocks had a weight that would slowly lower, moving gears which moved a hand which showed the hour. They could only be built in tall towers because the weights needed to fall a great distance or else the clocks would only work for a short amount of time. (ThinkQuest, n.d)
Galileo made an amazing contribution to the world of time. Galileo had noticed that the pendulum's period of swing appeared to be independent of the extent of the 'arc' of the swing and recognized its potential for timekeeping, but died before his work could be completed. It was Huygens (1629-1693) in The Hague, Holland, who eventually built the first successful pendulum clock in 1656. (ScienceMuseum, n.d)
Quartz clock operation is based on the piezoelectric property of quartz crystals. If you apply an electric field to the crystal, it changes its shape, and if you squeeze it or bend it, it generates an electric field. When put in a suitable electronic circuit, this interaction between mechanical stress and electric field causes the crystal to vibrate and generate a constant frequency electric signal that can be used to operate an electronic clock display. (Marrison, 1948)
Time management is commonly defined as the management of time in order to make the most out of it.
Time management is about managing your day affectively so you can achieve all that you want to achieve. It is also about making use of time today, so that you can obtain larger, long term goals whose deadline is sometime in the future. Being able to manage your time well will leave you with a feeling of mastery and accomplishment, knowing that you put your time to good use. (Barnard, 2007)
The notion "time is money" is quite true in the contemporary time as the world of today is faster than ever before and every one is in the race of making more and more money.
1. Barnett, Jo Ellen(1998) Time's Pendulum: The Quest to Capture Time - from Sundials to Atomic