Chemical Change A change that produces one or more new substances and may release energy. Chemical Property A second set of properties in all kinds of matter. Circuit A path that is made from an electrical current. Claws A sharp, usually slender, and curved nail on the toe of an animal.
The hourglass was one of the earlier timekeeping devices and has become a symbol of the concept of time. For thousands of years, devices have been used to measure and keep track of time. The current sexagesimal system of time measurement dates to approximately 2000 BC from the Sumerians. The Ancient Egyptians divided the day into two 12-hour periods, and used large obelisks to track the movement of the sun.
And midnight means the start of the next day, so we don't count that again. 2 x 11 = 22 times in any 24 hours. You can confirm this by taking any clock that you can set the hands on, like a wall clock or alarm clock-start the hands at 12 am, and spin the hands manually, counting all the times that the hands meet.