# Computers - Source: Kiddle (kids.kiddle.co), CC BY-SA 3.0, Kiddle encyclopedia, adapted from Wikipedia - Reading level: Grade 5 - Subjects: Robots and Computers, Technology - Topics: computers, computer, machines, information, people, called - Length: 1203 words, about 9 min - Published: 2025-10-17 - Original: - Page: - Open in Sprouts: ![Desktop computer clipart - Yellow theme](https://sprout.rootsofreason.org/media/kiddle-computers-cd55f2fb22.png) A drawing of a modern desktop computer. ![Woman-typing-on-laptop2](https://sprout.rootsofreason.org/media/kiddle-computers-6e5b31f555.jpg) Woman typing on a laptop ![Tabletunterricht 01](https://sprout.rootsofreason.org/media/kiddle-computers-7f1faf4c54.jpg) Kids using a tablet computer A **computer** is a smart machine that takes in information (input), works with it using special instructions (programs), and then gives you new information (output). Many computers can also save and find information using things like hard drives. Computers can connect to each other to form networks. This lets them share information and talk to each other. ## What Computers Do ![Traffic lights near Larne - geograph.org.uk - 407144](https://sprout.rootsofreason.org/media/kiddle-computers-4c3fbb322f.jpg) Traffic lights can be controlled by computers Computers can follow a set of specific rules very well. They can also run a list of instructions called a program. There are four main steps in how a computer works: - **Inputting**: Getting information. - **Storage**: Saving information. - **Outputting**: Showing information. - **Processing**: Working with information. Modern computers can do billions of calculations every second. This amazing speed lets them do many tasks at the same time. This is called multi-tasking. Computers help with many jobs where automation (doing things automatically) is useful. For example, they control traffic lights, vehicles, security systems, washing machines, and digital televisions. Computers are designed to do almost anything with information. They control machines that humans used to control. People use computers for things like math, listening to music, reading, and writing. ## Computer Parts: Hardware and Software Modern computers are made of electronic computer hardware. This hardware does math very quickly. But computers don't really "think" on their own. They just follow the instructions in their software programs. The software uses the hardware when you tell it what to do. Then it gives you useful results. ## How We Control Computers ![Backlit keyboard](https://sprout.rootsofreason.org/media/kiddle-computers-22ff060b97.jpg) A backlit keyboard Humans control computers using user interfaces. These are ways we interact with the computer. Input devices include keyboards, computer mice, buttons, and touch screens. Some computers can even be controlled with voice commands or hand gestures. Special devices can even use brain signals. ## Computer Programs Computer programs are made by computer programmers. Some programmers write programs in the computer's own language, called machine code. But most programs are written using a programming language. Examples are C, C++, and Java. These languages are more like everyday human language. A special program called a compiler translates these instructions into binary code. Binary code is the machine code that the computer understands and uses. ### What are Bugs? ![First Computer Bug, 1945](https://sprout.rootsofreason.org/media/kiddle-computers-4a55d82605.jpg) The actual first computer bug, a moth found trapped on a relay of the Harvard Mark II computer Mistakes in computer programs are called "bugs". Sometimes, bugs don't cause big problems. Other times, they can make a program or the whole computer stop working. This is called "hanging" or "crashing". Bugs are usually not the computer's fault. Computers just follow the instructions they are given. So, bugs almost always happen because of a mistake by the programmer. Admiral Grace Hopper, a famous computer scientist, first used the term "bugs" in computing. This was after a dead moth caused a problem in the Harvard Mark II computer in 1947. ## History of Computers ### Early Automation Most people find complex math hard to do in their heads. Imagine trying to calculate **584 × 3,220** without a calculator! People created tools to help them with math problems. Also, people often had to do the same math problem over and over. A cashier had to figure out change many times a day. This took time and led to mistakes. So, people made calculators to do these repeated tasks. This part of computer history is about "machines that make it easy to do the same math problem many times without mistakes." Some early examples of these machines include the abacus, the slide rule, and the Antikythera mechanism. The Antikythera mechanism was made around 150-100 BC. ### The Idea of Programming People didn't just want machines that did the same thing repeatedly. For example, a music box plays the same song over and over. Some people wanted to tell their machines to do different things. They wanted to "program" the machine. This means giving the machine different orders. This part of history is about "machines that I can order to do different things if I know how to speak their language." One of the first examples was built by Hero of Alexandria (around 10–70 AD). He made a mechanical theater that performed a 10-minute play. It used a complex system of ropes and drums. These ropes and drums were like the machine's language. They told it what to do and when. Some people say this was the first programmable machine. Historians don't always agree on which early machines were "computers." Many say the "castle clock," an astronomical clock made by Al-Jazari in 1206, was the first known [programmable](https://sprout.rootsofreason.org/r/kiddle/computer-programming) analog computer. It could adjust for the changing length of day and night throughout the year. Some consider this daily adjustment a form of computer programming. Others say the first computer was made by Charles Babbage. [Ada Lovelace](https://sprout.rootsofreason.org/r/kiddle/ada-lovelace) is often called the first programmer. ### The Modern Computing Era By the end of the [Middle Ages](https://sprout.rootsofreason.org/r/kiddle/the-middle-ages), math and engineering became more important. In 1623, Wilhelm Schickard made a mechanical calculator. Other Europeans made more calculators. These were not modern computers because they could only add, subtract, and multiply. You couldn't change them to do something like play Tetris. So, they were not programmable. Today, engineers use computers for design and planning. ![IBM Port-A-Punch](https://sprout.rootsofreason.org/media/kiddle-computers-c9c23cd5c1.jpg) IBM Port-A-Punch In 1801, Joseph Marie Jacquard used punched paper cards to tell his textile loom what pattern to weave. He could change the punch cards to program the loom to weave different patterns. This made the loom programmable. Charles Babbage wanted to build a similar machine that could calculate. He called it "The Analytical Engine." Babbage never finished his Analytical Engine. He didn't have enough money and kept changing his design. As time went on, computers were used more and more. People get bored doing the same thing repeatedly. In 1890, the U.S. Census Bureau had hundreds of people writing information on index cards. This was slow and expensive. Then, Herman Hollerith invented a machine that could automatically add up census information. The Computing Tabulating Recording Corporation (which later became IBM) made his machines. They rented these machines instead of selling them. This company was known for its great tech support. Because of machines like these, new ways of talking to machines were invented. New types of machines were also created. Eventually, this led to the computer as we know it today. ### Analog and Digital Computers In the first half of the 20th century, scientists started using computers. They had a lot of math to do, especially for things like launching a rocket ship. They wanted to spend more time on science questions and less time adding numbers. So, they built computers. These analog computers used analog circuits. They were very hard to program. In the 1930s, digital computers were invented. These soon became much easier to program. ### Powerful Computers Emerge Scientists learned how to build and use digital computers in the 1930s and 1940s. As they made more digital computers, they learned how to use them for complex tasks. ![EDSAC (10)](https://sprout.rootsofreason.org/media/kiddle-computers-a13ad7b1b5.jpg) EDSAC was one of the first computers that remembered what you told it even after you turned the power off. This is called (von Neumann) architecture. ## Picture credits - AJ from openclipart.org, CC0 () - Matthew Bowden www.digitallyrefreshing.com, Attribution () - Aigner Ronja, Kohlmeier Michelle, CC0 () - Albert Bridge, CC BY-SA 2.0 () - Colin, CC BY-SA 4.0 () - Kiddle encyclopedia, adapted from Wikipedia, not established () - Journey234, Public domain () - Copyright Computer Laboratory, University of Cambridge . Reproduced by permission., CC BY 2.0 ()