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.
The simple movement of your keyboard drawer takes a joule of work. Joules is used to measure kinetic energy. It is also known as Newton-meters. Newton is used in measuring force and meter is used in determining distance. One good example is a car moving at a certain speed and distance. Electrical Energy. Electrical energy is also energy in motion.