# Maybe I misjudged Stromberg. Any man who drinks Dom Perignon ´52 can´t be all bad.

The title is a James Bond quote, from The Spy Who Loved Me. A brief web search suggests that Dom Perignon 1952 retails at £950 a bottle, which probably explains why I so rarely get to judge Dom Perignon drinkers. Dom Perignon is champagne of course, which is noted for its bubbles.

Now, many physical properties are controlled by a balance of forces, for example, the shape of a bubble in champagne. The shape of a bubble is influenced by the surface tension of its surface, which exerts a force that tends to make the bubble a perfect sphere. It is also affected by the buoyancy force, which can bend the bubble out of a sphere.

Thus the ratio of the buoyancy force to the surface-tension force tells us if we should expect spherical bubbles or distorted bubbles. This ratio has a name, entertainingly, it is called the Bond number.

It is named after the English physicist Wilfrid Bond, not James, incidentally. The number is also called the Eötvös number, I guess it was independently proposed by both Bond and by Eötvös. When the number is much less than one a bubble will be a near perfect sphere, but when it is large a bubble will squashed.

It gets better, if you put the numbers in for champagne bubbles in the range of size around 1 mm, you can easily get values for the Bond number between 1 and 10. In a champagne bubble, the Bond number really can be 007.