Naked Science Forum

General Science => Question of the Week => Topic started by: nudephil on 19/08/2019 10:53:43

Title: QotW - 19.08.18 - Why does water boil over when you add pasta or rice?
Post by: nudephil on 19/08/2019 10:53:43

A question from Anthony:

When pasta or rice is added to boiling water, there is a sudden surge of the boiling water to the point where the pot boils over with bubbles. Why is this?

Penne for your thoughts? What's the answer?

Title: Re: QotW - 19.08.18 - Why does water boil over when you add pasta or rice?
Post by: alancalverd on 19/08/2019 17:54:55

Adding any granular material can nucleate bubbles in superheated water. If the added material contains starch or gluten, the bubbles can form a strong mat instead of bursting at the surface, so the next group of bubbles pushes the mat upwards and the pan boils over. Same with milk and many other substances.   

Title: Re: QotW - 19.08.18 - Why does water boil over when you add pasta or rice?
Post by: nudephil on 18/09/2019 13:34:25

Thanks for this answer Alan. Your contribution was included when we answered the question on our most recent show "Code Making and Breaking" and on the QotW podcast feed.