News 2019
Research Focus | Characterising Solutes With Sound
As a PhD student in rainy Dublin in the late 1990s, Dara Fitzpatrick suffered from frequent tonsillitis. Among his remedies was gargling with salt water. One day as he mixed his homemade solution, he heard a curious thing.
The sound of the spoon tapping against the glass as he stirred in the salt rapidly switched from a high-pitched clatter to a much deeper banging noise. Then, as he continued to stir, the tap-tap gradually rose in pitch again until it sounded like it did at the start.
Fitzpatrick wasn't the first to notice the acoustic dip. But unlike most who hear it, Fitzpatrick, an analytical chemist, was in a position to investigate the underlying mechanism. "It was in the back of my mind every time I made a cup of coffee,” he says. "I always wanted to see if it was a reproducible effect."
Read the rest of this BARDs research article on Physics Today.