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doctorwho:

Scientists claim to have invented their own version of Doctor Who’s famous sonic screwdriver.

The Dundee University researchers have created a machine which uses ultrasound to lift and rotate a rubber disc floating in a cylinder of water.

It is said to be the first time ultrasound waves have been used to turn objects rather than simply push them.

The study could help make surgery using ultrasound techniques more precise, the physicists said.

Ultrasound waves could already be made to push objects and scientists believed they could also turn them - but the Dundee University team claims to have now proved it.

They used energy from an ultrasound array to form a beam that can both carry momentum to push away an object in its path and, by using a beam shaped like a helix or vortex, cause the object to rotate.

The results of the sonic screwdriver experiment will be published in the American Physical Society’s journal Physical Review Letters.