Despite the eight million Google search results for his name, the question of whether Prince William eats muesli remains unanswered.

But if he does, he now has an explanation for a breakfast table phenomenon – thanks to a mathematician from Bath.

Dr Jonathan Dawes, of the University of Bath, explained the Brazil nut effect to the heir to the throne at the launch of a science event in London last week.

Brandishing a bottle containing yellow powder and stones, Dr Dawes outlined why the stones appear to defy gravity by rising to the top when the contents are shaken.

The interaction of the different- sized particles causes the effect, which means that nuts and raisins tend to gravitate to the top of shaken cereal packets and larger stones to the surface of gardens being dug.

Dr Dawes, of the university's Department of Mathematical Science, shared his wisdom with the Prince at the Royal Society's Summer Science Exhibition in London.

The university's exhibit at the event aims to show the importance of maths to everyday life – with arithmetic principles useful in areas from airport safety to the prevention of disease.

The display, one of 27 at the exhibition running until Sunday, has been organised by a team led by Professor Chris Budd, and also involves colleagues from the university's engineering departments.

He said: "Mathematics takes you well beyond your imagination; sometimes you intuitively expect one thing but in reality the opposite happens. Sorting out these ideas leads us to make discoveries of effects which have many important applications in real life.

"These can vary from weather forecasting to space exploration, and from power distribution grids to food processing."

He said predicting how different ingredients behaved was important for the food industry and Dr Dawes, a Royal Society research fellow, said mathematical theories could actually help to save lives in other sectors.

The university stand at the exhibition shows how the movements of groups such as flocks of starlings, shoals of fish and crowds of people can be predicted by mathematical modelling.

"These models help us in designing airports, football stadiums and other places where the safety of large numbers of people relies on understanding how crowds behave in emergencies," said Dr Dawes.

"Mathematics can save lives because by predicting how crowds will behave in an emergency, we know where to place fire exits so that people can escape the building as quickly as possible."

Another part of the exhibit looks at interactions that build up networks, ranging from social networking sites which link people together via common friendships, to the national grid, which needs to serve every home in the UK and balance out the distribution of energy.

Professor Budd said this proved the truth of the Six Degrees of Kevin Bacon game, which looks at how people are connected to each other: "On average, there's a path of only six friendships between any one of us and any other person in the world.

"Mathematics helps us explain why it's such a tremendously small world – and that's also a really useful fact when you're meeting new people at a party."

Professor Budd, who said researchers were looking at modelling the spread of illness such as swine flu or sexually-transmitted diseases based on their understanding of networks.

"Our overall message is that mathematics is far more than just the subject you did at school; it helps us to understand the complex world around us, and is being used to solve a huge number of problems.

"Our ability to tackle big questions such as climate change and population growth in the changing world of the 21st century will depend on mathematical ideas.

"This event will get people to engage with science and mathematics in ways they didn't even realise were possible before."