Mechanical computer facts for kids

A mechanical computer is a special kind of computer that uses moving parts like levers and gears to do calculations. Instead of using electricity, these machines work with physical motion. Think of them like super-smart machines made of tiny clockwork!

Simple mechanical computers include adding machines and mechanical counters. These often use turning gears to show numbers. More advanced ones could even multiply and divide. For example, some old accounting machines could even figure out square roots!

Mechanical computers were very important during World War II. They were used in complex bombsights, like the famous Norden bombsight, to help pilots aim accurately. They also helped ships calculate things like where to aim their weapons.

Even early spacecraft used mechanical computers! From the first human spaceflight by Yuri Gagarin in 1961 until 2002, every Soviet and Russian spacecraft had a special Globus instrument. This device showed where the spacecraft was over Earth using a tiny spinning terrestrial globe, along with latitude and longitude indicators.

Mechanical computers were still used in the 1960s, but digital computers started to become more popular. By the mid-1960s, electronic calculators with screens began to appear. Then, in the 1970s, small, affordable handheld electronic calculators became common. Because of this, mechanical computers became much less common in the 1970s and were rarely used by the 1980s.

However, mechanical computers might have a future! In 2016, NASA announced that its Automaton Rover for Extreme Environments program plans to use a mechanical computer. This is because mechanical parts can work better in the very harsh conditions found on planets like Venus, where electronics might fail due to extreme heat.

Cool Mechanical Computers Through History

Curta Calculator

Many amazing mechanical computers have been invented over time. Here are some of the most famous ones:

• Antikythera mechanism (around 100 BC): This ancient Greek device was like a mechanical astronomical clock. It could predict the movements of the sun, moon, and planets, and even eclipses! It's one of the oldest known complex gear mechanisms.

• Castle clock (1206): Built by Al-Jazari, this huge hydropowered clock was also an astronomical computer. It's sometimes called the earliest programmable analog computer because it could be set to perform different tasks.

• Astrarium (1348): Created by Giovanni Dondi dell'Orologio, this was a very complex astronomical clock. It had seven faces and 107 moving parts! It could show and predict the positions of the sun, moon, stars, and the five planets known at the time.

• Pascaline (1642): Invented by Blaise Pascal, this was one of the first mechanical calculators. It was mainly used for adding and subtracting numbers directly. It could also multiply and divide by repeating additions or subtractions.

• Stepped Reckoner (1672): Designed by Gottfried Wilhelm Leibniz, this mechanical calculator could add, subtract, multiply, and divide. It was more advanced than the Pascaline.

• Difference Engine (1822) and Analytical Engine (1837): These were designed by Charles Babbage. The Difference Engine was meant to calculate complex math problems called polynomials. The Analytical Engine was even more advanced and had many features found in modern computers, like memory and a way to be programmed.

• Odhner Arithmometer (1873): This calculator, invented by W. T. Odhner, was so popular that millions of copies were made until the 1970s.

• Curta calculator (1948): This tiny, hand-cranked mechanical calculator was small enough to fit in your pocket. It was very popular for its size and ability to perform all four basic math operations.

• MONIAC (1949): This was a unique analog computer that used water flowing through pipes and tanks to model or simulate the UK economy. It showed how different economic factors affected each other.

• Digi-Comp I (1963) and Digi-Comp II (mid-1960s): These were educational mechanical computers. The Digi-Comp I was a small 3-bit digital computer, and the Digi-Comp II used rolling balls to perform calculations. They helped people learn about how computers work.

Punch Card Data Processing

Before electronic computers became common, many calculations and data tasks were done using machines that worked with punchcards. These machines were called unit record equipment or electric accounting machines (EAM).

In 1887, Herman Hollerith developed a system to record and count census information using punch cards. Each card held information about one item or person. These machines became very common in businesses and governments during the first two-thirds of the 20th century. They allowed large amounts of data to be processed before electronic computers were invented.

Workers would feed punch cards through different machines in a specific order. Data on the cards could be added, subtracted, compared, and later, even multiplied. These machines could process cards very quickly, from about 100 to 2,000 cards per minute! They used mechanical, electrical, or optical sensors to read the holes in the cards. Many of these machines were controlled by a special removable board called a plugboard.

Electro-Mechanical Computers

The Harwell Dekatron computer, also known as WITCH, being restored in 2010.

Early computers that ran on electricity but were built using switches and relay logic (like the switches in a light bulb) instead of vacuum tubes or transistors are called electro-mechanical computers.

These computers varied a lot in their design and what they could do. Some could even handle very complex math problems. Even after vacuum-tube computers were developed, some relay-based computers stayed in use because they were very reliable, even if they were slower. Some were even built with duplicate parts to help find and fix errors. A few models were sold to businesses, but many were experimental machines built only once.

Here are some examples of electro-mechanical computers:

See also

• Analog computer
• History of computing hardware
• Mechanical calculator
• Turing completeness