As part of our commitment to STEM, and in recognition of National STEM Day on Friday 8th November 2024, the London Land Quality Team invited a local A-level student to their lunchtime learning session, to give a talk on the difference between sheens caused by pollution, and those that are naturally occurring.
Sheens are iridescent or shiny films on the surface of water that can form as a result of a petroleum hydrocarbon spill or can be produced naturally from the decomposition of natural plant and organic matter in soils.
Fun fact for the day: did you know that a quick and easy way to distinguish between a pollution and naturally occurring sheen is to poke it with a stick? Seriously! A petroleum-based sheen will swirl and elongate and when the stick is removed, the sheen will reform and may also adhere to the stick. Naturally occurring sheens will instead crack like a thin layer of glass, producing irregularly shaped platelets that resist reforming as the stick is removed. Who knew?!