Liquid crystals are substances that flow like a liquid but maintain some of the ordered structure of crystals. Liquid-crystal molecules tend to be elongated and to orient in specific directions.

The best smart thermostats we've tested can control your home's heating and cooling with your phone or voice—and might help you save on energy costs.

28 Years Later is now in cinemas, and its wild ending introduces Jack O'Connell's Sir Jimmy Crystal who looks a lot like Jimmy Savile.