Soap Bubble Structures by Kym Cox. Bubbles optimise space and minimise their surface area for a given volume of air. This phenomenon makes them a useful tool in many areas of research, in particular, materials science and “packing” – how things fit together. Bubble walls drain under gravity, thin at the top, thick at the bottom, which interferes with travelling lightwaves to create bands of colour. Black spots show the wall is too thin for interference colours, indicating the bubble is about to burst. (Photo by Kym Cox/2019 Science Photographer of the Year/RPS)

An ice hockey-themed crew in the 2018 Zaplyv festival of handmade inflatables in 300 Years of St Petersburg Park in St Petersburg, Russia on August 5, 2018. (Photo by Peter Kovalev/TASS)

A Southwest Airlines jet takes off from Reagan National Airport with a thunderhead to the east on June 20, 2017 in Alexandria, VA. (Photo by Jonathan Newton/The Washington Post)

Smoke plumes rise from Mount Etna, one of the most active volcanoes in the world in Sicily, Italy on June 28, 2016. (Photo by Etna Walk/Rex Feature/Shutterstock)

It's a 30-day-old Echidna baby, known as a “puggle” – one of only 24 ever bred in captivity. The proud parents are Tippy and Pickle of Australia Zoo. The tiny baby, whose s*x has not yet been identified, hatched from a soft egg and will continue to develop and nurse inside Tippy's warm pouch. (Photo by Australia Zoo/Rex/Sipa Press)

Julia Zlobina and Alexei Sitnikov of Azerbaijan gesture as they wait in the results area after competing in the ice dance free dance figure skating finals at the Iceberg Skating Palace during the 2014 Winter Olympics, Monday, February 17, 2014, in Sochi, Russia. (Photo by Vadim Ghirda/AP Photo)

Mr Lordi aka Tomi Petteri Putaansuu of the Finnish hard rock band Lordi gets the second jab of his Covid-19 vaccination from nurse Paula Ylitalo (R) in Rovaniemi, Finland, on August 1, 2021, amid the novel coronavirus / COVID-19 pandemic. (Photo by Jouni Porsanger/Lehtikuva/AFP Photo)

A high temperature alerts were issued as a record-setting summer heat wave continued to bake most parts of south China. (Reuters)