Computer scientists are now using ‘Bayes’ theorem’ to build computers that are more intelligent and even able to learn for themselves. Here we’ll show how you can use just sweets and pots and a pinch of Bayes’ theorem to find out who stole a chocolate biscuit! You’ll discover how likely it is that someone with chocolate smudged on their fingers is the real culprit. You can run this is an activity with your friends at home or ask your teacher to run it in class.

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One of the most exciting branches of computer science is called machine learning. Machine learning aims to find ways for computers to solve complex problems by learning for themselves. For instance, a computer can use trial and error when it is learning how to play games and win by learning from its mistakes.

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Security is very important on the internet. You often need to prove to another person that you know something but without letting them know what the information actually is (because they could just copy and use it). For example, you might need toconvince an online music shop that you know your password for their website without sending them the password itself.

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One of the most important concerns with using modern technology is how to keep your secrets secret. For instance, you wouldn’t want anyone to intercept your emails and read them or to listen to your mobile phone conversations. This is especially important when someone is sending their credit card details to an online shop. And it is crucial that banks, big businesses and governments know that any information they send through the internet stays safe.

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Computers are essentially electronic machines for handling information: storing, processing and transmitting it.

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Computers don’t just automatically know how to do things – they need software programmed for them by people. Amobile phone, for example, has software installed to tell the on-board computer how to carry out different functions. This includes running the menus, digitising your voice to transmit it, and even playing music or games. The softwarebreaks down these functions into individual tasks, each of which is processed by a particular algorithm. ‘Algorithm’ may sound technical, but it is just a way of describing how to do something. An algorithm is a list of instructions, like following a recipe to bake a cake.

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Nowadays, lots of computer display screens are of a type called an LCD screen. LCD stands for ‘liquid crystal display’. If you’ve used a calculator, MP3 player, mobile phone, laptop or flat screen TV today, you almost certainly would have been using an LCD screen.

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A lot of what people use computers for involves images. Most web pages are now absolutely stuffed with colourful pictures, and we all love taking holiday photos on a digital camera or looking at pictures of our friends online. But all of this would be impossible if computer scientists hadn’t developed clever ways to store and transmit images digitally.

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Computers do many wonderful things: from running medical equipment and scientific simulations to searching the web and playing music or games. Yet all these different computer applications ultimately boil down to straightforward mathematical operations: adding or multiplying two numbers together, checking to see which of two numbers is the largest, and so on. This maths is performed by electrical circuits made up of logic gates. Logic gates are small electrical components that each perform a simple job, but can be built up in circuits to do very complicated processes.

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Modern computer processors have been improving rapidly since they were first developed in the 1940s. Computer systems have advanced in two main ways: how fast they can run calculations and how much information they can store in a small space. DNA (deoxyribonucleic acid) is the chemical that stores the information of life in all our body’s cells, and nowresearchers are looking into ways of building DNA computers!

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