1. The sundial was one of the 1st timekeeping devices created, and dates back to 1) ____ Roman and Greek societies. It used a central 2) ____ rod and called a gnomon, and the sun's light to cast a shadow onto a platform which was marked to show the hours of the day. 2. The 1st water clock was created around 500-600BC. It was widely used in Egypt, Greece and Arab world. The concept was quite simple and used naturally consistent movement of water to 3) ____. This was done by allowing water to 4) ____ either in or out of a marked container. 3. By far the most modern device on this list, the atomic clock was developed in 1949. It is accurate to a couple of 5) ____ over several million years, making it by far the most 6) ____ timekeeping device to date. 4. Commonly seen even todat, the hourlass uses similar 7) ____ to that of water clock. It uses 2 glass bulbs, one above the other, with a small opening in between. The sand inside gradually falls from top to bottom, indicating that a 8) ____ amount of time as passed. 5. Obelisks were the next logical step from the sundial, and used the same basic 9) ____. They were towering pointed 10) ____ which cast a shadow across a large public area, similar to how a gnomon did.

timekeeping devices

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