History of latitude facts for kids
Measuring your position on Earth has been a big challenge for explorers and sailors throughout history. One important part of knowing where you are is finding your latitude. Latitude tells you how far north or south you are from the equator. People have used many clever tools and methods over thousands of years to figure this out.
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Early Ways to Measure Latitude
Ancient Greek Explorers
Long ago, around 325 BC, a Greek explorer named Pytheas traveled far north to Britain and even beyond, reaching the Arctic Circle. He observed the midnight sun, where the sun stays visible all night during summer. The Greeks used his findings to understand latitude better.
They had a few ways to measure latitude:
- They measured how high the Sun was in the sky at midday. They used a tool called a gnōmōn for this. A gnōmōn was like a tall stick that cast a shadow, and its name originally meant "interpreter" or "judge."
- They also looked at how long the day was during the summer solstice (the longest day of the year).
- Another method was to measure the Sun's height during the winter solstice (the shortest day of the year).
Mapping the World
Later, a Greek geographer named Marinus of Tyre (who lived from about 70 to 130 CE) was the first person to try and give every place on his maps a specific latitude and longitude. This was a huge step towards creating accurate maps of the world.
Tools for Sailors
The Arabian Kamal
Starting in the late 800s CE, sailors in areas near the equator began using a tool called the Kamal. This simple instrument helped them measure the height of the North Star (Polaris) above the horizon. However, the Kamal could only be used in places where Polaris was low in the sky.
The Mariner's Astrolabe
From the 1400s to the 1600s, the mariner's astrolabe became popular. This tool could measure the angle of the Sun from the horizon at noon. At night, it could measure the angle of a known star. Using the Sun meant sailors could measure latitude even in the Southern hemisphere, where Polaris isn't visible. But they needed special tables that showed the Sun's changing position throughout the year. A famous set of these tables was published in 1496 by Abraham Zacut, a Jewish scholar from Spain who was living in Portugal.
Backstaffs and Sextants
In the 1500s, the backstaff was invented. This instrument measured the length of a shadow cast by the Sun. It was improved over time, leading to tools like the Davis quadrant. These tools were used alongside early versions of the octant and the sextant.
The sextant eventually became the most important tool for measuring latitude and is still used today! The famous scientist Isaac Newton wrote about the sextant in his notes, but he didn't publish them. The first working sextants were built around 1730 by John Hadley and Thomas Godfrey.
See also
