Description: Researchers are investigating the reasons why elastic objects skip better than rigid objects.
Start: April 15, 2013
End: December 31, 2016
- Sponsor: Office of Naval Research
- Principal Investigators: Daniel Maynes and Tadd Truscott
Most people have tried to skip rocks across a lake, getting the rock to skip as far and as many times as possible. Usually the right angle or a precision toss can give good results. However, what most people do not know is that a recent discovery has shown that such rigid rocks and other objects would skip better across the water if they were made of a more elastic material. Elastic rocks? That sounds a little extreme, but the physics of this discovery has more far-reaching effects than just entertainment, including substantial naval and defense applications.
This research, being led by Daniel Maynes of BYU and Tadd Truscott of USU, is focusing on the actual mechanics of the skipping of elastic bodies on water. It has already been shown that an elastic object skips much better across the water than a stiff object. This discovery was originally made by Jan von Heland, who performed tests on various materials to see which skipped best across the water. Starting in the 1980s, Heland began performing experiments that tested various materials and shapes, trying to invent something that could bounce on the water. He eventually patented his invention in 2004, which was the Waboba Ball, a sphere made of elastic material. He found that elastic materials skipped off of the surface much better than a rigid object of another material. The researchers are testing the different conditions of elastic bodies using sphere objects, changing variables of the experiments related to the elasticity of the material and also how the sphere is being fired into the water.
Differing from Heland’s research in this area, Maynes and Truscott are focusing solely on why elastic spheres bounce so well across water. The goals of this research are to deepen understanding of the physics behind Heland’s discovery and to determine what factors influence the skipping of bodies across water. These experiments are being executed through the help of an accurate shooting mechanism to allow the researchers to collect precise data for the parameters of the experiment.
The discoveries from this research have the potential to improve naval weaponry. The technique of skipping projectiles across the water in naval combat has been used since the 1700s. Further discovery on this method of combat can enhance the capabilities of our naval weaponry to provide better projectile tactics. In particular, this application can be used in defending swarm attacks on our navy. Swarm attacks are assaults to overwhelm the defenses of an opponent. A better understanding of the technology of skipping projectiles across the water’s surface can improve the weaponry of defending a forceful attack and better prepare ships against an opponent.
In addition to defense strategies, this research also applies to objects that are dropped from the air into the water, including flotation devices, supplies, and weaponry. Although many might not realize at first the importance of knowing how to best skip a rock across the lake, when looking a little bit deeper under the surface, it is easy to see the significant applications that can come from investigating this common leisurely activity.