Measuring membrane permeation rates through the optical visualisation of a single pore - video MutchGreg MetcalfeIan PapaioannouEvangelos TsochataridouSotiria NeaguDragos RayBrian MerinoRosa I. SanjuanMarisa L. OreraVĂ­ctor M. MetcalfeIan S. 2020 Here, an optically-transparent single crystal has had a single pore laser-drilled into it, which has subsequently been infiltrated with molten carbonate. Upon a change in the gas composition of the external environment of the single crystal, a gas bubble within the molten carbonate responds by increasing in volume. In this example, the gas bubble was equilibrated in a gas mixture containing 1.1 mol% CO<sub>2</sub> before being exposed to a flowing mixture containing 50 mol% CO<sub>2 </sub>at the same time as starting visual acquisition. Thus, the bubble increases in size. The entire single-crystal model membrane was enclosed in an <i>in-situ</i> cell at ~550C, and provides a dynamic equivalent of a typical membrane experiment. Note, the original clip has been accelerated x10.