In ancient times, there were no clocks. What do people use to measure time?

Also known as sundial, sundial.

The "table" in the Guibiao is a pillar or stone pillar standing upright on the ground, and the "Gui" is a slate extending horizontally from the heel of the table to the north.

Whenever the sun turns due south, the shadow falls on the water of Guiyu.

By measuring the length of the shadow, we can calculate the winter solstice, summer solstice and the time of each solar term.

When the shadow is the longest, the solstice of winter comes, and when the shadow is the shortest, the solstice of summer comes.

It is the oldest and most common astronomical instrument in China.

It's time to drip at night.

Also known as leaky carving and leaky pot.

There are two main types of clepsydra: drainage type and water receiving type.

Most of the early water leaks were drainage type.

The bottom side of the leaky kettle leaks water, and the grid fork and the closing tongue rise again, so that the leaking arrow floating on the surface of the leaky kettle drops with the water surface, and the scale on the leaking arrow indicates the time.

Later, the water-receiving type was created, in which water was injected into the kettle at a constant flow rate from the leaking kettle, and the leaking arrow floating on the water surface of the kettle rose with the water surface to indicate the time, which improved the timing accuracy.