Telling time: First attempts to track time within each day date back over 5000 Years to the Egyptian sun dials. (worksheet on the development of the sun dial)
The first clocks: Clocks were developed to track time both night and day, and also to provide a more accurate measure of time. One of the earliest clocks was the water clock, using a constant flow of water it could track the passing of hours and minutes. Following the water clocks were the mechanical clocks with an escapement at the heart. This mechanism allowed stored energy in the form of a wound spring, or heavy weights to be released in a controlled fashion.
(demonstration with simple mechanism of escapement). http://www.youtube.com/watch?v=80tLBQkCbr4&feature=related
The age of Quartz. Quartz was a crystal found to resonate (vibrate) at a certain rate when a very low electric current was put through it. Quartz clocks and wrist watches were more accurate than wound mechanisms and became the norm in the 1970’s and are still in wide use today.
The atomic clock: A very advanced piece of time telling equipment the atomic clock works on the same principal as the quartz clock, (vibrations), only this time it is the vibrations of an atom.
(readings from the internet). Could be done with lap tops and then cut and paste to create the poster. But need students to read and understand content.
Divide the class and give each group a reading on a time keeping method. Each group is then required to present their findings as a poster and give a 1 to 2 minute presentation of their findings. The posters then get put around the wall of the room.
Reasons for keeping time: Give some examples of where we may take time telling for granted. Eg a sports game, two or four equal periods of time to give each team the same opportunity. Meeting a person, time and place. The school day. Etc.