Bored of water coming out of your hose in a straight line? Here’s a video showing you how to change all that with a loudspeaker and a sine wave generator.
Holography, from the Greek words for “whole” and “writing/ drawing”, is the technique for creating three-dimensional images. Discovered accidentally by physicist Dennis Gabor in the 1940s, it was only when lasers developed in the 1960s that the first optical hologram was created. Using halogen-based photographic emulsions to record 3-D images on 2-D surfaces, in simple terms holograms split and stretch recorded light into 3-D shapes.