Review: Cheltenham Science Festival

Last week, the Focus team made the short trip from Bristol to Cheltenham for the annual science festival – 6 days of enlightening events and science-related shenanigans.

 

On the Thursday, we sent our web writer James along to some of the talks and exhibits. Here are three of the surprising things he learnt during his mind-expanding trip.

Fact #1: Helium isn’t the only gas that changes your voice.

Most people know that breathing in helium makes your voice go squeaky, but did you know that there’s a gas which has the opposite effect? Sulfur hexafluoride is denser than air, so inhaling this gas causes the voice to deepen into Barry White territory – and that’s just the ladies.

These voice-changing gases were one of the subjects of a talk given by the scientist Wendy Sadler and the tenor singer Greg Tassell. Together, they explored the science behind singing: how the vocal chords work, how technology can be used to manipulate the voice, and why breathing in helium makes you sound like Donald Duck.

To demonstrate this effect, Greg Tassell inhaled a balloon full of helium before launching into an extremely reedy rendition of Nessun Dorma. Wendy Sadler explained that the voice changes because the speed of sound is much higher in helium than in air. This alters the natural frequency of the throat, meaning that the higher frequency components (‘harmonics’) of the voice are amplified more than the lower ones. The end result is a comical change in the voice’s ‘timbre’.

On the flipside, gases that are denser than air, such as sulfur hexafluoride, have the opposite effect. In this video, some American newsreaders try it out for themselves:

Fact #2: The city of Gloucester sends fish pies to the Queen.

Bizarre fact of the day: Gloucester has a long-running tradition of sending pies to the reigning monarch – pies made out of a slimy, eel-like fish called the lamprey. This practice began in the Middle Ages, and chefs in Gloucester are about to make a special lamprey pie for the Queen’s Jubilee.

Quite a strange subject for a science festival, you may be thinking, but the lamprey featured in a talk about ‘survivors’ – organisms that have survived on Earth nearly unchanged for millions of years. The distinguished palaeontologist Richard Fortey has written a book and made a BBC TV series about these survivors, so he was the perfect person to wax lyrical about them.

The lamprey, for example, has been around for over 300 hundred million years, meaning that it has lived through three mass extinction events, including the K-T event around 65 million years ago which wiped out most of the dinosaurs.

And there are other organisms with even more impressive survival skills. Take stromatolites, for instance. Some of these rock-like structures, formed in shallow water by microorganisms such as cyanobacteria, are thought to be around 3.5 billion years old – amongst the earliest evidence for life on our planet.

Studying these survivors gives scientists a unique insight into the history of life on Earth, helping them to understand how some organisms manage to adapt and cling onto their fragile existence, whilst others kick the bucket as soon as the going gets tough.

Meanwhile, the Queen is no doubt looking forward to her lamprey pie. Either that or the corgis are going to be treated to a very special fish supper.

Fact #3: A surprising amount of fun can be had with an MRI scanner.

In the Discover Zone, many visitors stumbled across a mysterious tray filled with all manner of objects: cherries, blackberries, sardines, a fresh rose, tomatoes, a pig’s eye… it looked like the bounty from a very strange Pick-Your-Own farm.

In reality, these curiosities were being used to demonstrate magnetic resonance imaging (MRI). Next to the tray was a tabletop MRI scanner developed by the instrument makers Bruker. Usually, MRI scanners are huge instruments that take up a whole room, but this desktop version allows objects to be scanned anywhere, quickly and easily.

As they scanned the various items, researchers from University College London’s Centre for Advanced Biomedical Imaging were on hand to explain how MRI scanners work. A powerful magnet inside the scanner causes the protons inside the object’s water molecules to align themselves with the magnetic field. When a radio frequency (RF) electromagnetic field is applied, the spins of some of the protons are flipped. Then, when the field is turned off, these protons return to their original position, emitting an energy signal that can be used to image the object’s interior.

Visitors to the MRI exhibit could have a go at identifying some of objects that had passed through the scanner. Can you guess what’s shown in the image below?