Crystals step up to a new surface
You can buy sunglasses that become darker when you go outside. Similarly, some crystals reversibly change color from, say, clear to blue when exposed to certain wavelengths of light.
These are nice tricks. But researchers in Japan have now found that light can trigger a more profound reaction in certain crystals–a change in shape. The crystals are the first that scientists have gotten to reversibly change shape just by shining the right light on them, says Masahiro Irie of Kyushu University.