There are various opinions about the first civilization to have measured time.

Some say the Hindus, some say the Greeks, some say the Egyptians.

It is known that more than 7000 years ago, the Hindus (Indus Civilization) used to gaze at the sky and measure the time by looking at the position of stars and the Sun. This let them understand time and they used it in various activities connected with religion, astronomy, and astrology. In fact, Vedic astrology was solely dependent on time of birth, which was calculated without any mechanical devices.

The Egyptians were known to have used the water clock. This device could measure time based on a constant flow of water that moved through a port. They were also the first people to have made a calendar consisting of 365 days.

The Persians and Sumerians made the hourglass, where time was measured by the amount of sand transferred from one chamber of the device to the other. In spite of the name, the device did not have to measure only an hour. There were hourglasses that measured by the minute, minute and a half, and so forth.

Similar to the Hindus and Egyptians were the Chinese who measured time in various ways including the direction of the wind. But the Chinese were surprised to see the mechanical clock, which was brought to China for the first time by European explorers. Europeans were the first to make a mechanical clock similar to the ones we use today.

The History of Clocks

The history of clocks dates back over many centuries. The actually date for the first clock is disputed among historians, but they do agree that the word 'clock' was first used in 14th century (around 400 year ago). The word clock is derived from the Latin 'clocca' meaning bell.

The Sun

The first methods for telling the time relied on the movement of the sun across the sky. When the sun was directly overhead it was the middle of the day, or 'noon' and when it was on the horizon, it was early morning or early evening, depending if it was in the east or the west. However, this method was not very accurate, but nevertheless, it has been used for countless years, from early man, right though to today.

The Sundial

This method of using the sun to tell the time was later adapted into one of the oldest forms of clock, the sundial. By using a vertical pole on a horizontal surface, the pasting of daylight hours could be easily tracked. The first sundials were thought to have been used at around 3,500 BC (about 5,500 years ago) and again this for of telling time is still used today, and not just as decoration in gardens.

By placing an angled vertical plain onto a circular horizontal plain, like a clock face and placing it in the sun, a simple clock has been made. As the sun shines onto the sundial, a shadow is produced, and this points to a number. This number is the hour of the day. It is a very simple idea, but it was still not very accurate, as on a cloudy, or rainy day, the sundial would be useless. Nevertheless this method was used for over 2000 years without much improvement. Then something new came along.

The Water ClockAround 1400 BC (around 3,400 years ago), the Egyptians invented the water clock, or as they called it the Clepsydra (pronounced KLEP-suh-druh). These water clocks were made from two containers of water, one higher than the other. The water then travelled from the higher container to the lower container through a connecting tube. The containers had markings on them to show the level of the water and these marks told the time.

The idea of a water clock caught on and became very popular, not only in Egypt, but as far as Greece. The design was improved upon over the years and adapted to become easier to use and more accurate. One of the more notable changes was the addition of a floatation device. As the water dripped from the higher container to the lower container, the level of water rose and with it went the float. This float was connected to a stick with notches that, as it moved higher and higher, moved a hand around a clock face.

Water clocks were far more popular than sundials for two important reasons. First, unlike the sundial, the water clock did not depend on cloud cover and could even work during the night. This meant that the time could be at hand no matter what the light level. The second reason why people preferred this new way of telling the time is that water clock were far more accurate than the traditional sundial.

The Pendulum Clock

Before the pendulum clock was invented, a German man called Peter Henlein, invented the Spring powered clock in 1510. Sadly, the style was wrought with problems, such as inaccuracy.

As the clocks became more accurate, so a new device was needed and so in 1577, Jost Burgi invented the minute hand. This addition had many problems and was not considered practical until the a man named Christian Huygens invented the pendulum clock. He first came up with this new item in 1656 and by the 1600's the clock also hand a successful minute hand.

The idea of the pendulum clock was simple and is still very popular today. As the pendulum swings left and right, it turns a wheel with many teeth on it. This wheel turns the hour hand and the minute hand on clock face. On the first clocks on this design, the pendulum needed to swing over a lager area of about 50 degrees, but as time progressed and the clocks improved the pendulum needed to swing less, only 10-15 degrees. However, pendulum clocks also had problems, the major one being that they would stop running after a while and had to be restarted.

This problem was solved around 1840 when an external battery was fitted and by around 1906 the batteries could be fixed inside the clocks.

Time Zones

Clocks became so popular that in 1884 the first time zones were drawn up. As the Earth turns, each part of the world experiences 'local time' differently. In 1884, delegates from 25 different countries met and agreed to divide the world into zones. Greenwich was chosen to be the central point, and the world was thus divided into 24 zones, each 15 degrees apart (24 x 15 = 360 degrees or a full circle).

The Quartz Crystal Clocks In the 1920's the first Quartz clocks were invented. These work by applying a certain voltage and pressure inside the clock. This will vibrate or oscillate the Quartz at a constant rate. This vibration is measured electronically and governs the movement of the hands on the clock, in a very precise manner, making them very cheap and very accurate.

These are the clocks that are used everyday in our houses, offices and schools and in many cases on our wrists.

In most cases, digital displays have replaced the hands of the clocks, so that the time is displayed numerically. Features of these timepieces include stopwatches, timers, alarms, and multiple time zones.

There are other types of clocks, such as atomic clocks. They are currently the most accurate clocks we have, and they keep time accurately to within a second over tens of millions of years.

• Beaker
• 2 liter plastic bottle
• Scissors or razor blade
• Ring stand
• Rubber stopper
• Rubber tubing
• Wax pencil
• Water
• Food coloring

1. Cut off the bottom of a two liter plastic bottle with a pair of scissors or a utility knife.

2. Draw a line with a wax pencil just above the bottom edge of the top half of the

   the two liter plastic bottle.

3. 3

   Unscrew the cap on the bottle and insert a rubber stopper in its place. Feed the vinyl tubing into the hole in the top of the rubber stopper and use the clamp to clamp the tube on the same side as the opening of the bottle.

4. Turn the plastic upside down and insert it into the ring on the ring stand while putting the other end of the tubing into the beaker.

5. Fill the bottle with water up to the line you drew in Step 2 and add food coloring to color the water.

6. Loosen the clamp enough to allow a steady drip of water to run into the beaker while using your other hand to start timing with a stop watch. Use the wax pencil to mark the water level every 10 minutes.

7. Pour the water out of the beaker and into the plastic container that is positioned in the ring stand and repeat the drip process. Mark the water level every five minutes this time.

Press mode key at any time to exit.

Press mode, then press adjust to change time zones.

TO SET TIME AND DATE:

Press and hold alarm on/off for about 5 seconds until hour flashes.

Press adjust to change hour.

Press alarm on/offto move to minutes. Press adjust to change minutes

Press alarm on/offto move to seconds. Press adjust to change seconds

Press alarm on/offto move to month. Press adjust to change month

Press alarm on/offto move to date. Press adjust to change date

Press alarm on/offto move to day of week. Press adjust to change day of week

Press mode key to save to exit.

TO SET ALARM:

Press mode to go to alarm screen (AL shows above temp)

Hold the alarm on/off button for about 5 seconds and the hour will flash.

Press the adjustbutton to change the hour.

Press the alarm on/off button again to move to minute

Press the adjustbutton to change the minutes

Press the mode key to save and exit