Seen and heard
Weird and wonderful stories from the world of physics
The physics of the perfect burger
It’s summer in the northern hemisphere so the perfect time to get the barbecue out. But what’s the most effective way to grill a burger or a steak – flip the meat once or many times? Some chefs think you should flip only once as doing so multiple times will mean less browning and therefore less flavour. Others, however, claim that regular flipping results in a more even cook and is also about 30% faster, given that each surface of the meat is exposed to heat relatively evenly and has less time to cool down. Mathematician Jean-Luc Thiffeault from the University of Wisconsin in the US has now created a “simple” model to demonstrate this speedy cooking time for flipped meat (arXiv:2206.13900). Assuming a burger is an infinite thin slab and has symmetric thermal properties – i.e. the same at the top and the bottom – he used a 1D heat equation to find that flipping the patty once results in a final cooking time of about 80 seconds. This falls for every subsequent flip so that 20 flips results in a 20% drop in cooking time. Taking Thiffeault’s model to its mathematical extreme, a burger could cook in 63 seconds – if you flipped it infinitely many times. That would challenge even the most experienced grillers.
Diamond: the game
Synchrotrons and some board games have at least one aspect in common: they involve things going round in a circle. Mark Basham and Claire Murray from the UK’s Diamond Light Source synchrotron and Matthew Dunstan at the University of Cambridge have now seen the parallels by creating “Diamond: the Game”. Suitable for anyone aged 10 and over, the game – which takes no more than half an hour to complete – puts players in the role of a researcher at Diamond. By visiting different beamlines while progressing round the board, participants learn about the diversity of science that is done at the facility – including physics, chemistry, cultural heritage and more. The game has been tested by over 200 students and was released online as a free-to-print game in 2020. Since then, Diamond has been played by more than 14,000 players in more than 30 countries worldwide. Whether it makes being stuck on the beamline at 2 a.m. more bearable is open to question.
Prize first
It took a long time coming, but for the first time, two young women have been crowned UK Young Scientist of the Year and UK Engineer of the Year in the same year. Connie Gray from Liverpool and Avye Couloute of Surbiton, both 14, bagged the science and engineering prizes respectively in The Big Bang UK Young Scientists and Engineers Competition. Gray’s research involved comparing the structure of birds’ feathers to determine why some birds cannot fly. Her work aims to help conservation efforts in areas of the world affected by climate change. Couloute, meanwhile, invented a system that monitors carbon-dioxide levels inside buildings. To test her system, she built a scaled-down pavilion and was able to show how the system can automatically improve indoor air quality using ventilation and other techniques. Bravo.
Sizzling research
Cooks in some parts of Asia will put moist bamboo chopsticks into their pans to judge the temperature by watching the bubbles that form and listening to the sizzling sound they emit. Zhao Pan of Canada’s University of Waterloo and colleagues have now looked at the physics underlying this clever test (Physics of Fluids 34 062107). They did this by placing wet paper, moistened chopsticks and water droplets in hot oil and used microphones and high-speed cameras to see what happened at different temperatures. They found three distinct types of “bubble events” when a water droplet enters hot oil and that these events occur at oil temperatures that are favourable for cooking. “This simple eye and ear measurement is accurate to within about 5–10%, which is pretty good when we consider that a typical temperature for frying food is higher than 150 °C,” says Pan.