Instead of using sound to form images, MR uses the combination of a strong magnetic field, and radiofrequency waves.

The patient lies at the centre of a really strong magnet which causes all the hydrogen molecules in the body to line up with the magnetic field. A radiofrequency is then used to knock them out of this alignment (sounds ‘Ouch!’ doesn’t it!). When this radiofrequency is removed, all the molecules hurry back to their positions. This ‘return’ emits a signal which is amplified to form an image.

What started way back in the 1960s has turned into a process that leaves us gobsmacked at present… Currently scanners are producing images of real people that look like illustrations in anatomy textbooks.  The possibility of MR post-mortems as an alternative to cutting up a body is also being considered.

Source: The Naked Scientist

• Amazing, isn’t it?! Here’s more info on MRI
• The Visible Human Project: Very interesting MRI scans
• Cool experiments with magnets
• An electromagnet is a type of magnet in which the magnetic field is produced by the flow of an electric current. Make your own electromagnet...