If you’ve seen a big air-variable capacitor, you may have noticed that some of the plates may have slots cut into them. Why? [Mr Carlson] has the answer in the video below. The short answer: you can ...

If you'd asked us a few years ago if we’d heard of Loop Earplugs, we wouldn’t have known what you meant. After all, a device which lets you control the loudness of your surroundings seems too good to ...