oxygen

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Liquid oxygen is magnetic

Liquid oxygen sticks between the poles of a strong magnet until it boils away into its gas state. This is because it has unpaired electrons, which make each oxygen molecule a tiny magnet with a dipole. Normally, when oxygen is in a flask or in the air, these microscopic magnets point in all directions, cancelling out and meaning that there’s no net magnetic field. When it pours over the permanent magnet, the magnetic molecules all slightly align, creating an induced magnetic field, which reacts with the permanent magnet, making the oxygen stick to the poles. This is called paramagnetism. Click here to watch the video.

Pyrite suns

Some pretty cool things can happen as a dark and stinky organic rich mud filled with the life forms of rot slowly turns into rock in a multiplicity of processes known under the umbrella term of diagenesis. In the first stage water gets squished out of the pore spaces in between the sediment grains as the weight of further sediment being laid down above compresses it, and it often has dissolved elements such as iron and sulphur in it.

In the boundary zone (if there is one, which is not always the case) between anoxic mud and oxygenated water, a stratigraphic hierarchy of microorganisms are at work, each squeezing energy out of the excretory products of the one above along its own chemical and enzymaytic pathways. As you go deeper into the mud the reactions get progressively more anoxic, and ions that started out oxidised such as sulphates get reduced to sulphide. At that point they join with any iron in the solution to produce pyrite, often with the direct help of archaea, in this case as discs of radial fibrous crystals that grew outwards pushing the surrounding mud/shale away as they expanded.

Loz

Image credit: Bijoux et Mineraux