02400BC+-+1599

2400 BC - 1599
__** Heron of Alexandria **__

Heron of Alexandria (who had the awesome nickname of simply Hero) was a Greek mathematician who was born in Roman controlled Egypt in the year 10 AD. He lived until 70 AD (which back then was still pretty impressive) and during that time he published a number of mathematical and engineering theorem, as well as creating some of the machines he thought up. Today, the mathematical theorem he’s most famous for is Heron’s Formula, which can find the area of a triangle from its sides. However, he also devised and created the first steam engines, vending machines (dispensing holy water of all things), a wind-powered organ, a completely mechanical ten-minute play, and many other creations. He also devised a type of syringe, for all of you who love getting shots.

== =__The Astrolabe__= =Although the exact inventor is not verified, the credit for the first version of the astrolabe often goes to a Greek named Hipparchus in 150 BC. The astrolabe was made with a flattened disk with a hollowed center (like a pizza pan). Inside the “pan” is a number of rotating disks which help track the movements of celestial bodies, like stars and planets. Some of the functions that an astrolabe can help someone calculate include the time of day (this was before watches and cell phones), when sunrise and set occur, the direction he faces, and other spherical (shaped like a ball) astronomical things. The actual setup and function of the astrolabe depended on who made it and when, as there were many different versions made throughout the thousand years after its creation. The same idea was used in making a small, handheld device to determine latitude at sea. This was, naturally, called a Mariner’s Astrolabe (because it was used by mariners). = =__**Abacu**____**s**__=

2nd century BC- Chinese invented their abacus. 2700- 2300BC- Sumerian Abacus was made. 600BC- Persians started using their own version of the abacus. 300BC- A marble counting board was made on the Greek Island of Salamis. 11 century AD- Romans started widely using their form of the abacus.

Many cultures have their own version of the abacus. The most famous versions are the Chinese and the Romans abaci.

__Xu Yeu__
(227bc - 185bc) Was an astronomer and a mathematician. He had many writings on the subject of mathematics. It was his writings that hinted at the first designs of the Suanpan. He never held a goverment position, but he was respected by those how did and they would invite him to talks about

__Chinese Abacus__
The Chinese abacus was called the Suanpan. It was first described by the writings of Xu Yue. The abacus had a height of 20 cm and would be at least seven columns or more in width. Unlike traditional counting boards used in elementary schools the Suanpan can be used for more advanced math such as division or multiplication.

__Roman Abacus__
The Roman abacus was the first portable calculating device. It was based after the Babylonian abacus. It was not nearly as accurate as bigger less portable devices.