This video illustrates one way in which semi-permeability can work. We have used a jam jar with a tight mesh placed over the top. When the jar is turned upside down, air pressure will stop the water from pouring out. Larger objects, such as a pencil, are unable to pass through the mesh and are therefore ‘resisted’ by the ‘membrane’, whereas a smaller object like a toothpick is able to pass through into the ‘cell’ and is not ‘resisted’.

The video supports the Europlanet Mars Collection of Educational Resources - 1. Extremophiles: An introduction to life found in extreme environments, exploring the kind of stresses we may find on Mars and how life can adapt to survive these.

Europlanet 2024 RI has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149.