Ellen Phiddian
Cosmos science journalist
It’s January, and summer in Australia. If you’re at the beach right now, put your phone down. If you’re not, you should be preparing for your next trip, so read on to learn how best to skip stones.
Scientists have long been interested in the physics of stone skimming.
Other than helping people get the pleasure of making a rock to bounce off water multiple times in succession, stone skipping physics has applications in aviation and industry: things like the effect of icing on aircraft surfaces, and landing aeroplanes on water.
Researchers at the University of Bristol in the UK, have brought a new formula to the field, as well as a piece of advice: if you’re using heavier rocks, try one with a curvier bottom.
In general, previous research has confirmed what you probably know about stone skipping: flatter and lighter stones are more likely to skip better, and should be as close to parallel to the water as possible.
This study, which is published in Proceedings of the Royal Society A, focusses on heavier rocks and shallower bodies of water.
“The physical understanding and prediction of skims for bodies that are, in a sense, both fatter and heavier than previously addressed may prove helpful for future direct numerical studies,” write the researchers in their paper.
The researchers developed a mathematical model to predict how rocks would skim across water bodies.
They found that increased curvature of the underside of the rock made the skim more successful, as well as smoothness and thinness playing an important role.
They also point out that a larger mass can lead to deeper and longer skimming motions.
As well as an interesting diversion for any lake or beachside walks, the researchers believe that their “work shows a range of skimming motions which could be relevant in the aircraft icing context”.