No. 4 – The Radiometer, a.k.a. The Light Mill.

210px-Crookes_radiometer

No aggregation of strange and strangely pleasing stuff would be complete without a radiometer (or, if you’re British, a light-mill).   It was one of the attention-getters in every science museum gift shop in the past, though I notice they seem to be harder to find lately.

Place a radiometer in the sun, and its vanes will spin merrily around inside the vacuum of its sphere.  See it in action here:

http://archive.org/details/RadiometerSolarSpinningSpindleLightMill

though in strong sunlight it will go much faster, to the point of making little fairy-like “tink” sounds as it spins.

I’ve read explanations of the how and why, and it still seems like magic to me.  Since my understanding is tenuous at best, I’ll direct you here http://math.ucr.edu/home/baez/physics/General/LightMill/light-mill.html rather than subject you to my painful paraphrasing.

To have one of these in a window on a sunny day is weirdly satisfying, like having  one of the engines of the world made visible.

No. 3 – The Dawn Chorus.

rooster The Dawn Chorus is a phenomenon where many species of birds start their morning singing at the first light of dawn.  Maybe it’s for the defense of breeding territories, or an attempt to find a mate;  no one truly knows why.

Roosters and mockingbirds are probably the most familiar of the morning singers, but go outside in the early hours and listen closely – you’ll hear  a variety of species greeting the day simultaneously.  (In some places you don’t need to listen closely – the  chorus  in Stratford-upon- Avon, England was loud enough to wake me.)  It begins tentatively with one or two birds, but soon is in full throat.

There is also an electromagnetic phenomenon which occurs at dawn  and is caused by the same energy that drives the auroras borealis and australis.  Related to birdsong?  Unknown.  What is known is that the earth wakes up singing.