Fluffy to Flat

High geekdom here... Some researchers in Spain have directly observed a layer of Lead atoms on a Silicon substrate change their state as a function of temperature. Microscopy has been able to observe single atoms for a decade or two but it has always been a static view. This website has a video. Here are two frames -- they did digital processing but the individual bumps you see are individual Lead atoms.

Don't move a muscle. Lead atoms on a silicon surface go from a flat arrangement at 135 Kelvin (top) to a corrugated structure at 43 Kelvin. The microscope captured the phase transition by continuously imaging the same set of atoms over the entire temperature range. (See video.)