Guinness bubbles
Do bubbles in Guinness flow downwards?
We are used to seeing bubbles float up in a glass of beer, but bubbles in Guinness appear to break the rules. Do the bubbles really sink in Guinness, or is it just an illusion? If the bubbles go down, where do they go? Why do they all end up at the head?
We are used to seeing bubbles float up in a glass of beer, but bubbles in Guinness appear to break the rules. Do the bubbles really sink in Guinness, or is it just an illusion? If the bubbles go down, where do they go? Why do they all end up at the head?
In collaboration with Richard Zare (Stanford University) our group obtained the first video evidence that the bubbles in Guinness do actually go down the inside of the glass just after the beer is poured [1]. The effect had been predicted using computational flow dynamics by Nurul Hasan and Clive Fletcher at University of New South Wales. Together with Marguerite Robinson (University of Limerick), Andrew Fowler (Oxford University), and Stephen O'Brien (University of Limerick) we subsequently published a physical model to explain the bubbly flow [2]. To learn more, click on one of the links below.