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The FREE online science and technology book

CCD chip from a webcam.

Atoms Under the Floorboards book cover

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Want to know how your earbuds make music, how telephones squeeze sounds down wires, what graphene is, or how windows can clean themselves? You've come to the right place! Here you'll find simple explanations you can really understand—hurrah!

Hard stuff... made simple!

Explain that Stuff is an online book written by British science writer Chris Woodford (author of many popular science books for adults and children, including Atoms Under the Floorboards: The Surprising Science Hidden in Your Home). It includes 450 easy-to-understand articles, richly illustrated with easy-to-understand artworks and animations, covering how things work, cutting-edge science, cool gadgets, and computers. We take the "pain" from explain and the "tough" out of stuff! There's more information on this website than in your average expensive science book, it's continually updated, and it's completely free to use! Explain that Stuff also helps to support curriculum learning (conventional STEM education and home-schooling).

What's hot in June 2020?

In the news now...

Swarm of ancient stars, M80 (NGC 6093).

Space rockets

NASA and SpaceX have collaborated to send astronauts into space... which is a great excuse to remind ourselves how rockets really work.

A bar of pure soap


As you surely know, washing your hands thoroughly with soap and water is a great thing to be doing right now. But why, exactly, is soap better than water alone?

Real Player screenshot

Streaming media

If you're stuck at home at the moment, you're probably doing an awful lot of "streaming" over the Internet. What is it and how does it work behind the scenes?

Smokestack black smoke air pollution

Air pollution

From Delhi to Paris and London to New York, some (not all) of the pollutants in our air have fallen in the last few months. But why, given all we know about the importance of breathing clean air, is air pollution still such a big global problem?

Artwork explaining how Earth heats up when greenhouse gases trap heat.

Climate change

Following devastating summer bush fires in Australia and spring flooding in the UK, more people are asking themselves whether extreme weather events really are signs of a growing climate emergency.

Most popular

Model of a steam turbine at Think Tank science museum, Birmingham, England.

These are some more of our classic, ever-popular articles:

  1. Water pollution: Rivers and seas take a long time to recover from the effects of careless human treatment. What causes pollution and what can we do to stop it?
  2. Electricity: The most versatile and useful form of energy in our world, electricity is going to become a whole lot more important in future.
  3. Nanotechnology: Can we build a brave new world just by shuffling atoms and molecules under a microscope?
  4. Magnetism: One of the first bits of science people studied, magnetism is still just as relevant today in everything from electric cars to body scans at the hospital.
  5. Gears: Wheels with teeth carved around them can make you go faster or bump up your power—and here's how!
  6. Batteries: We all need electricity, wherever we happen to be, so thank goodness for batteries—miniature power plants you can carry in your pocket!
  7. Electric motors: These amazing machines turn electricity and magnetism into movement, powering everything from handheld toothbrushes to bikes, cars, and trains.
  8. Cloud computing: Why buy yourself an expensive computer or programs to go with it when you can get access to something just as good over the Internet?

What else is on our site?

The hundreds of detailed articles on our site are divided up into a number of broad topical areas, which we've listed below. We've also given you a rough idea of the kind of questions you're going to find answers to in each section!

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Now you've found us, don't lose us! Why not join our friendly Facebook page, where we post cool science and technology news? You'll find our photos on Flickr. We regularly add new articles and constantly update and improve our older ones. If you use RSS, subscribe to our articles feed to find out about new stuff as soon as we publish it.

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Like this site? Get the book!

Atoms Under the Floorboards book cover

Why do skyscrapers wobble in the wind? Why can't you cool your home with a giant block of ice? Could you microwave your dinner with a cellphone? What's the hidden connection between a bicycle and a suspension bridge? If questions like this are constantly buzzing round your brain, you'll love my new book, Atoms Under the Floorboards: The Surprising Science Hidden in Your Home, published worldwide by Bloomsbury. Please click here to find out more.

Please do NOT copy our articles onto blogs and other websites

Text on this website is copyright © Chris Woodford 2000, 2020. All rights reserved. Full copyright notice and terms of use.

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