Many chemical reactions produce gases as a stream of bubbles out of a solution. Here we see the electrolysis of an aqueous sodium hydroxide solution (NaOH), which produces hydrogen gas on the cathode (left) and oxygen gas on the anode (right). In timelapse, the gas bubbles nucleate on the electrode, slowly growing larger. Once the the bubbles are large enough to detach, though, they rise so quickly they look like they disappear! The large buoyant forces on them drive that brief journey to the surface. By contrast, the smaller bubbles rise slowly, held back by their lesser buoyancy and the viscous drag they experience. (Video and image credit: Beauty of Science)