Times, as we understand and measure it, is a human invention. The science of studying time, as well as the art of
making instruments that measure time, is known as horology. Different instruments have been used to keep track of
time over the years, in an effort to count time in equal units. Sundials, or sun clocks, were used as early as 3500 B.C.
and divided daylight time into equal hours. In Europe, in the fourteenth century, the hourglass was used. Time was
then measured by having a quantity of sand, water, or mercury run from the upper to the lower part over a set period of
time. The first spring-powered clock was invented in Germany around 1510. The power for this clock came from a
metal coil inside called a mainspring. To operate the clock, a person would wind the mainspring by turning a key.
Battery-powered clocks were first used in the 1840s, with electric and quartz-powered clocks coming into use in the
early 1900s.With the invention of battery and electric-powered clocks, there was no longer the need to wind a
mainspring. As a result, time-keeping became much more accurate. 【題組】17 Which of the following is also called “sun clocks”？
(A) Sundials (B) Hourglasses
(C) Spring-powered clocks (D) Battery-powered clocks
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