# A question about champagne bubbles

1. Jun 7, 2005

### Raparicio

This is an interesting questions that occurs when we have a glass of champagne (or cava).

why all the bubbles that are born in one point, are lineed when they go to surface?

An the other hand: why are they at constant velocity, and not with acceleration?

Chin chin!

R. Aparicio.

2. Jun 7, 2005

### brewnog

Here are my thoughts.

The reason something travels at constant velocity is because the forces acting on it are balanced. In the case of champagne bubbles, the buoyant forces balance the gravitational forces and fluid resistance when the bubbles are rising at a constant speed.

Now then, bubbles are pretty small, light things, so naturally, they float in champagne. However, their smallness also means that they accelerate quickly having been formed (like a truck takes longer to accelerate than a motorbike, for example). So the fact is, for a portion of the bubble's life, it is accelerating; it just happens so quickly you probably don't notice it.

Another element which might have crossed your mind is the hydrostatic pressure gradient between the top and bottom of the glass, causing the bubbles to change size on their journey. In any case, even the tallest champagne flutes probably aren't tall enough for this to make a difference.

3. Jun 7, 2005

### Raparicio

Champagne

Dear brewnog

I am more or less in the same direction than you. I think that bubbles are one just near the other becouse the upper bubble has a depresion, and goes in the must simple way.

By the other hand, I thing that velocity is really constant, but becouse of the virtual mass or something like this. Bubbles will change in the way to up, but I thing mass of bubbles is not significative in comparation with Champagne (or cava) density.

I will think it a little more. Is only a christmas curiosity.

Best reggards.

4. Jun 7, 2005

### brewnog

Sorry Raparicio, I think I misunderstood your original question slightly.

As for the reason the bubbles float up in lines following on from one another, I would like to think that this is due to surface imperfections on the glass causing the bubbles to collect at 'peaks' on the glass surface (since the glass is not completely smooth). The effect is similar to raindrops falling off a leaf.

The reason that bubbles travel in straight lines is simple enough.

If you find the language barrier difficult, I'm sure that Clausius2 would be happy to respond to a private message in Spanish.

5. Jun 8, 2005

### Oxymoron

Here is a question for you:

Why do the bubbles form? And why dont they form before you open the bottle, only after?

6. Jun 8, 2005

### Raparicio

Becouse of the presure?

I think that the liquid part has a cuantity of gas, that only "escapes" when presure is not atmosferic.

I don't know exactly, only is a suposition.

And, what about the incremental mass becouse of the "induced mass"?

Last edited: Jun 8, 2005