a solar car?

- when you shoot photons (=light) on one side with very much energy (okay... EXTREMELY much), you can make it move

Or

because plants don't do anything in the dark, but in the light they can move (a bit at least), and these three are an improvement - the earlier you get them, the bigger the improvement
Or

: It is a big improvement (of course), and if you put gold into the light, it might begin to melt (again, very much light is needed... more than they have in Hammerfest^^)