Angbu-ilgu facts for kids
The Angbu-ilgu is a special kind of sundial from Korea. It looks like a bowl or a hemisphere (half a sphere) and uses the sun's shadow to tell time. It was first created in 1434, during the reign of King Sejong, a famous and wise king of Korea. This clever device helped people know the time of day and even the season.
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What is an Angbu-ilgu?
The name "Angbu-ilgu" means "bowl-shaped sun clock" in Korean. It's designed to be concave, which means it curves inward like a bowl. This unique shape allows it to track the sun's movement very accurately.
Parts of the Angbu-ilgu
This sundial has several important parts that work together:
- Hour lines: These lines are drawn on the inner surface of the bowl. They show the different hours of the day.
- Seasonal lines: These lines help tell the time of year. Because the sun's path changes with the seasons, these lines show how the shadow falls differently throughout the year.
- Yeongchim: This is the pointer, or gnomon, that sticks out from the center of the bowl. It casts the shadow that tells the time.
- Sibanmyeon: This refers to the surface where the hour lines are marked.
- Horizontal surface: This is the flat base or rim of the sundial.
How Does the Angbu-ilgu Work?
Like all sundials, the Angbu-ilgu works by using the sun's light to cast a shadow from its pointer (the Yeongchim). As the sun moves across the sky during the day, the shadow of the Yeongchim moves across the hour lines on the bowl. Where the shadow falls tells you the time.
Telling Time and Seasons
The curved shape of the Angbu-ilgu is very important. It allows the sundial to show not just the time of day but also the time of year. The seasonal lines on the bowl help with this. For example, the shadow might fall on one set of lines in summer and another in winter, showing how the sun's position changes with the seasons. This made it a very advanced tool for its time.
Who Made It and Why Was It Important?
The Angbu-ilgu was first made in 1434 under the direction of King Sejong. King Sejong was a brilliant ruler who cared deeply about his people and supported science and technology.
King Sejong's Vision
Before the Angbu-ilgu, it was hard for ordinary people to know the exact time. Clocks were rare and expensive. King Sejong wanted everyone, especially farmers, to be able to tell time easily. Knowing the time was crucial for daily life, farming, and planning activities. So, he ordered his scientists to create a simple, public timekeeping device.
Public Access to Time
The Angbu-ilgu was placed in public places, like busy streets and markets, in the capital city of Hanyang (modern-day Seoul). This meant that anyone could look at it and know the time. It was a huge step forward in making scientific knowledge useful for everyday people. It showed King Sejong's commitment to improving the lives of his subjects through innovation.
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