Observe a fresh water layer (with your eyes, not a CTD!)

Sometimes you actually see fresh water layers (see with your eyes, not a CTD or some other instrument) floating on top of denser waters, not only in your kitchen and with the help of dye, but for real. In this case, you see the layers because the shadow of a pole appears twice — once on the surface itself, and once on the interface between the layers.

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See below: Shadow on the surface between the red lines, on the interface between green lines, and the reflection on the surface between blue lines.

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I took these pictures on a trip to Husum with my sister and her family.

As frost starts melting, and the roof is getting dry, oh! The sun is up.

My office looks out directly onto the roof of our main lecture theatre, and it is fascinating how much you can observe just by looking out of a window and onto a roof.

Below is a picture of one of the first cold mornings we had this year. As the sun rose, more and more of the roof was lit and the frost melted away. Can you see where the shadow used to be just minutes ago from the shape of the still-frozen frost?

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Some time later, the first corner was completely dry, while other parts of the roof were still wet, the only-recently-lit parts of the roof still had frost n them, and some parts of the roof were still frosty in the shadows.

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I really enjoy making random observations that I bet most people wouldn’t even notice, but I take pictures of and write a haiku about. Good thing I have my blog :-)