Monday, June 24, 2024
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Zenithoptera lanei, the Clearspot bluewing, is perhaps one of the most beautiful dragonflies. Found in Central America and northern South America, they fly through grassy marshes or clearings, spotted by bright flashes of their shimmering, blue-as-sky wings. These dragonflies rest with their wings folded, metallic blue hidden from the world. When male bluewings fight over territory, they will spread their wings when their rivals approach, displaying the blue of their inner wing.
Like the Morpho butterfly, the bright blue feathers of a Kingfisher, the shimmering green of a beetle’s chitin, and peacock feathers, the blue of Zenithoptera lanei wings is structural colouration. Structural colouration is colour from small structures that interfere with visible light. In structural colouration, only the wavelengths you see are reflected, and while the others are transmitted through the medium. This is in contrast to pigment colour. Pigments absorb certain wavelengths of light except the one you see. Structural colours are much more resistant to fading.
Clearspot bluewings UV-bluish colouration is called pruinosity. This is a common structural colouration in dragonflies that reflects ultraviolet light that comes from wax filaments and plate-like crystals covering the body and wings. Some scientists suggest that this wing UV reflection has a role in sexual and age recognition.
Why all this discussion on dragonfly colouration? Well, I think it's cool. Also, this week I finished my demo on thin-film interference, which (obviously) is centred around the structural colouration of dragonflies. Also on Monday, I met with Dr Gary White (GWU professor and editor of The Physics Teacher), who kindly lent us his fabric of spacetime setup for Astronomy on the Mall. On Tuesday, I tested a demo on vortices (related to how insects fly!).
We had Wednesday off for Juneteenth, so Piper, Kai and I set off at 8 in the morning for a 7-mile hike at Sugarloaf Mountain in Maryland. Not only was it gorgeous, but the trail was covered in all kinds of berries. 99% of compound berries in the Northeast are edible, so I spent the whole hike snacking on blackberries and wineberries (and blueberries)! I made a specific effort to eat as many wineberries as I could as they are an invasive species (EAT THEM). We then drove back to Shenkman and Kai and I hosted a potluck where we celebrated Charles’ birthday (I made dumplings and fried mantou), which was delicious and also exhausting. Thursday, I made too much fried rice, finished up my vortex demo, and received some logistical changes for Astronomy on the Mall. On Friday, I realised I had a captive audience of cousins to test my demos on, so I sent out a mass request for critiques.
Saturday was BarbequeFest and also Astronomy on the Mall day! This was big for me, as this is the event I had to organise for all the interns for this summer. Because of the heatwave this weekend, we got moved into the Arts and Industries Building (which has been closed for a while). We got our tables set up pretty quickly and began our mission to make physics and astronomy seem super cool and awesome to the public. Given that there was consistently a crowd around our 8-foot fabric of spacetime demo, I think we might have succeeded. I spoke to a lot of adults with little astronomy knowledge and got lots of compliments on my explanations (someone asked if they could leave me a Yelp review?), which felt fantastic and made me feel like I’m perhaps not too bad at science communication. Sunday, I made turon (banana spring rolls) to bring to my cousins, and then spent the day with them and my great-aunt. Good stuff!
Maia Chandler