Sound Waves: The Symphony of Physics • 2017 • 1 episode • 1h:57m

Making Sound

At the Palace of Westminster, Helen teams up with scientists from the University of Leicester to carry out state-of-the-art measurements using lasers to reveal how the most famous bell in the world - Big Ben - vibrates to create pressure waves in the air at particular frequencies. This is how Big Ben produces its distinct sound. It's the first time that these laser measurements have been done on Big Ben. At the summit of Stromboli, one of Europe's most active volcanoes, Helen and volcanologist Dr Jeffrey Johnson use a special microphone to record the extraordinary deep tone produced by the volcano as it explodes. Finally, at the University of Cambridge's Institute of Astronomy, Helen meets a scientist who has discovered evidence of sound waves in space, created by a giant black hole. These sounds are one million billion times lower than the limit of human hearing

1/2 • 2017 • Physics