The Most Ingenious Devices of Ancient China

Hinzugefügt: 2026-05-18

[00:00:00]More than 400 years before Christ, China had already invented a form of radar. It was known as an early city invasion warning system. They buried a drum inside a pit underground and placed identical setups all around the city walls. Then they stationed soldiers with the sharpest hearing inside those pits.

[00:00:15]By listening to the drums vibrations and comparing the sound intensity from different locations, they could determine the enemy's exact position and launch an effective counterattack. In modern terms, the drum acted like a vibration wave receiver using seismic vibrations to locate enemy movement. To test this ancient technology, they headed to Chinatown to find a suitable ceramic jar. Then they stretched a piece of leather across the top and secured it tightly with rope. At first glance, it looked like a professionally built drum.

[00:00:41]When struck, it produced a deep powerful sound. But according to newly uncovered historical records, the ceramic jar needed to stand 40 in tall and hold up to 200 L of water. That was far larger than they had imagined. So they bought a much bigger ceramic jar and used goatskin to make the drumhead. First, they removed the hair from the hide, then degreased it with lime water. After scraping off the remaining fat and hair, they stretched it out to dry, mounted it over the drum, and trimmed away the excess material to ensure even tension and stable sound quality. Next, they traveled to an abandoned gold mine. The mine's massive underground tunnels were perfect for simulating an invading army digging beneath city walls. They dug a hole 30 ft away from the mine shaft and planned to lower the drum into a vertical pit 15 ft deep. Then excavation would begin from the tunnel 30 ft away.

[00:01:26]If the drum vibrated or produced sound, it would prove the method actually worked. To first measure what kind of vibrations digging would create from 30 ft away, they lowered a seismograph into the 15-ft shaft. Then Jamie started digging with a pickaxe. The instrument detected faint seismic vibrations. Next, they lowered the drum into the shaft.

[00:01:44]Two people began digging at ground level, while two others listened directly above the buried drum. The seismograph clearly recorded the digging sounds, and although the signal was extremely weak, the drum produced faint sounds that matched the rhythm of the excavation. The listeners above ground could actually hear the drum vibrating.

[00:01:59]They could hardly believe it. Even with all the surrounding noise, they were still able to hear a drum buried 15 ft underground. That was almost unbelievable. It's a remarkable demonstration of just how extraordinary the ingenuity of ancient Chinese civilization truly was.