electrons

Imagine robots that operate without electronic components. Well, this week scientists at a robotics lab in Japan revealed a creation that could bring the scenario a step closer to reality. The team has created what looks to be a Technicolor inchworm made of motile gel that not only crawls by itself, but changes color depending on the environment it's in. And its creators say that this creeping, self-propelled goop might one day find its way into robots.

1. Einstein showed that light travels in bundles called quanta, which are at
the heart of the light-emitting diode. When electrons in a semiconductor-based diode move from one side to another, they shift to a less excited state, releasing energy in the form of photons. Channel these, and you get a bright, long-lasting light source.

2. In 1917 Einstein demonstrated that when a photon comes into contact with an atom, it can trigger a chain-reaction release of additional photons from