Photochromic paint is pretty nifty – under exposure to light of the right wavelength, it’ll change colour. This gives it all kinds of applications for temporary displays. [Jiri Zemanek] decided to ...

I’ve described this effect before. Video is an illusion; it’s really a series of still images that are shown so rapidly our eyes and brain interpret them as continuous motion. If you can time some ...

RUSHTON 1 has recently described a series of ingenious experiments which demonstrate the effect of humming on the induction of stroboscopic patterns in non-fluctuating illumination. By introducing a ...