How does a spirit level work? There’s just about enough space for an air bubble, and when lined up correctly will tell you if your shelf, mirror or curtain rod is in the correct orientation.

THERE’S no end of secrets tucked away inside your iPhone – including a hidden spirit level feature. Yes, your iPhone has a built-in function that can work out if a surface is level, so you ca… ...

The level is made from two disks cut from leftover 15mm borosilicate glass. Between the disks is a 4mm cavity for the liquid (ethyl alcohol) and the air bubble to move around.

A spirit level is a must if you want your home to have straight, even lines, but what is that bright-green liquid inside the bubbles? It's not just water.

As I reported at Search Engine Land last night you can now make your mobile Google search results page into a bubble level (or spirit level). Just go to Google on your mobile device and search for ...