Do you remember the T-shirts that could change colour? I never owned one, but temperature-sensitive clothing was all the rage in the early 1990s. Put one on, press your hand against it (or simply hang it on the radiator) and watch the colour change! But it wasn’t long before the novelty wore off – roughly around the time when everyone realised that their sweaty armpits suddenly became very visible...
I am still impressed by colour-changing materials, although I’ve always been baffled by why they work. A great man to ask how they work would be Hendrik Ball, owner of Grand Illusions. A TV producer by trade, he now runs an online shop selling science curiosities and has an infectious passion for using science to amuse and enthral. Hendrik also curates a ‘toy museum’ (“We don’t do dolls!”) that boasts a vast collection of over 20,000 unusual playthings. You can see many of these in action on Hendrik’s YouTube channel (which has an incredible 40,000 subscribers and over 10 million views).
Grand Illusions is delightfully quirky and eccentric, and certainly not just for kids. Which brings me back to those chameleon-esque T-shirts. I’ve done my homework and discovered that colourchanging materials work thanks to some pretty crazy chemistry: the molecules of ‘thermo chromic’ substances change their shape and arrangement at about 27°C. And I was delighted to discover Grand Illusions have some colour-changing offerings – which are far trendier than a T-Shirt. For the Guru reader who likes something just a little different, Grand Illusions is well worth checking out.