Falling Bridges, Dress Codes and Bats

Bridge Collapse

Today I read an article about how the Tacoma Narrows Bridge collapses in 1940. This was not due to resonance. Resonance is what causes a glass to shatter at the right pitch, and what enables you to be able to swing high on a swing by pumping at the right rate. The reason the bridge collapsed was to do with vortices that formed as the wind passed over the bridge. Over time, these vortices caused the bridge to oscillate, like a leaf fluttering in the wind. A cable snapped, enabling the flutter effect to increase, and become more and more violent until the whole thing collapsed.

The article: The Strangest, Most Spectacular Bridge Collapse (And How We Got It Wrong) is a longer read on the topic.

Meeting the Pope Dress Code

I saw a picture of the Trumps meeting the pope in the Vatican. They look like they're at a funeral and so I wondered why. I looked for pictures of the Obamas meeting the pope, and Mrs Obama was again wearing black with her hair covered. I then looked for Queen Elizabeth II and she was wearing a black long dress and veil too. So what are the rules?

Checking on the etiquette at the Vatican website, it seems that women must wear at least short sleeves and the knees should be covered, and men must wear trousers and at least short sleeves. So why are so many wearing black?

For papal hearings, the dress code is stricter. Women are required to cover their heads and wear mourning clothes, and men weara tailcoat, although the dress code has been relaxed somewhat since the 1980s, as we can see since the men are not wearing tailcoats. Further, Prince Philip seems to always wear his military uniform. In 2014, Queen Elizabeth did not wear black for her meeting with Pope Francis, and nor did the Duchess of Cornwall when she met him this year, although she did when she met Pope Benedict XVI in 2009.

Hijabs and the Police

I saw an article about an American policewoman wearing a hijab, and a discussion about whether the hijab should be allowed. My immediate thought was that it should, because to disallow it would create an extra barrier for muslim women to join the police, and I'm sure muslim women are underrepresented in the police force. My only concern is safety and whether it could be used to strangle the officer in the same way that a non-clip-on tie could be used.

In 2016, the Scottish police introduced an optional hijab as part of the official uniform. It's black with a black and white chequered band on the edges. The Metropolitan Police have allowed hijabs since about 2001.

Bats

There are 18 species of bat in the UK. The tiny common pipistrelle bat, weighing around 5g, with a body little more than the size of a fifty pence piece, can eat up to 3000 small insects in one night!