Prof Dr Daniel Grieser
Institute of Mathematics

• Photos from the lecture

Anyone who has ever blown soap bubbles knows them: The shimmering spheres, sometimes small, sometimes large - and always round. Or have you ever seen a square soap bubble? Why is that? The soap bubble solves a mathematical problem that has fascinated people for over 2,000 years: How do you trap a certain amount of air in the smallest possible area? We will explore the mathematics of the smallest areas in this lecture, as well as its little sister, the mathematics of the shortest distances: Where should three friends meet in order to walk as little as possible from home to the meeting point? In which direction do you have to fly from Oldenburg to take the shortest route to China? Perhaps you would like to try this out beforehand - preferably not on a world map, but on a globe!

Moderator: Carola Schede

Wednesday, 11 March 2009
16.30 to 17.30
Audimax, Hörsaalzentrum

Here are some internet links where you can find out more about soap bubbles, smallest surfaces (often called minimal surfaces) and shortest paths:

A lot about soap bubbles (on the chemistry of soap skins, where the colours come from, how to make a good soap bubble liquid, etc.)

'Palace of Soap Skins' is a very nice film about soap skins. Here you can find information about it, including how to order it as a video. Here you can watch some excerpts from the video for free.

Here are some pictures of double bubbles. These are two soap bubbles that are connected. As you can see, the resulting structure is made up of spherical parts. However, it is much more difficult to understand that the smallest surface area is actually created in the way shown in the pictures than in the case of a single bubble. Although mathematicians have been thinking about soap bubbles for over 150 years, they were only able to solve this problem 9 years ago!
And here are a few more pictures of several soap bubbles and the like.

You can find the puzzle sheet here. The solutions can be found here.

Hint for the bee task on the puzzle sheet: Mirror the bee at the edge of the forest and the beehive at the river.

Do you have any questions or would you like to write to me about the lecture? My email address is

And now have fun with soap bubbles, spheres, circles, rectangles ...
Your Daniel Grieser