5 Tools We Use to Measure Time Sundials. Water Clocks. - A water clock uses the flow of water to measure time Mechanical Clocks.- clock are wound with a key, and this tightens the mainspring. Quartz Clocks- Inside a quartz clock or watch, the battery sends electricity to the quartz crystal through an electronic circuit. Atomic Clocks.- a clock device that uses a hyperfine transition frequency in the microwave
When all parts of a circuit are composed of conducting materials, then it's possible for current to flow in the circuit, and we say that the circuit is "closed".