Lessons

Unstoppable Time

Measuring time is one of the most common measurement tasks: e.g., "How much time is left in the lesson?", "How long do you have to boil an egg?" These and similar questions can be answered with the help of the clock.

DAY, MONTH, AND YEAR

Throughout history, the measurement of time has also become more accurate. The higher values were determined by astronomical phenomena: the Earth’s orbit around the Sun gave the year, the full cycle of the phases of the Moon gave the month, and the Earth’s rotation on its own axis gave the day. For more precise measurements, a day was divided into 24 hours.

The sundial measures only by daytime

FLEETING TIME

Shorter periods of time used to be measured, for example, by the change in length of a candle as it burned, or by water flowing through a small hole in a pot. Today we still use the hourglass, in which dry sand always flows from the top to the bottom through a narrow section between two identical bulbs. With mechanical clocks, of course, more accurate measurements can be made.

The hourglass measures a specific period of time

	TOWER CLOCK
The clocks in the church steeples were visible to all, and the quarter, half, three-quarter and full hours were also indicated by sound. These devices required a special operator, as the gravitational force of suspended weights ensured a constant supply of energy and the weights had to be wound up regularly. Pendulum clocks are smaller versions of tower clocks. In these, too, weights provide the kinetic energy. Miniaturisation also produced pocket watches and wristwatches, which now have a coil spring as the energy storage device, with manual or automatic winding.

TOWER CLOCK

The clocks in the church steeples were visible to all, and the quarter, half, three-quarter and full hours were also indicated by sound. These devices required a special operator, as the gravitational force of suspended weights ensured a constant supply of energy and the weights had to be wound up regularly. Pendulum clocks are smaller versions of tower clocks. In these, too, weights provide the kinetic energy. Miniaturisation also produced pocket watches and wristwatches, which now have a coil spring as the energy storage device, with manual or automatic winding.

Structure of the tower clock

WHAT’S THE TIME?

Reading the exact time on mechanical watch takes some practice, and with the rise of digital watches, fewer and fewer people are able to do it. However, the real fanatics make it difficult even for the experts! The dials of backwards running watches are also reverse numbered. The 24-hour dial makes it easier to read the hours, but the minutes and seconds are a real headache.