Walking on Water
As kids we casually glanced at them for mere seconds, until we found something else that attracted our attention. As we grew into adulthood, we found their abilities almost mystifying. Known commonly as “pond skaters” or “Jesus bugs,” water striders have long baffled scientists with their unique ability to “walk” on the water. Only two individuals have ever been successful at walking on water—Jesus Christ and the apostle Peter (Matthew 14:24-32). [Of course, Peter’s walk was very short lived, as he soon began focusing on the boisterous wind.] Nature does not routinely allow objects to propel themselves across the surface of water. Water striders are an exception to this rule.
The cover of the August 7, 2003 issue of Nature has a beautiful picture of a water strider on dyed water with the caption “Walking on Water.” Inside the issue, David Hu and his colleagues discussed the mechanism underlying the puzzle that has perplexed researchers for decades. They noted:
Previous investigators have assumed that the hydrodynamic propulsion of the water strider relies on momentum transfer by surface waves. This assumption leads to Denny’s paradox: infant water striders, whose legs are too slow to generate waves, should be incapable of propelling themselves along the surface. We here resolve this paradox through reporting the results of high-speed video and particle-tracking studies. Experiments reveal that the strider transfers momentum to the underlying fluid not primarily through capillary waves, but rather through hemispherical vortices shed by its driving legs (2003, 424:663).
The researchers utilized food coloring and thymol blue to perform dye studies in an effort to visualize the vortices in the water. According to Newton’s third law, in order to move forward, an animal must push something backward. These specialized creatures have wax-covered, hairy legs that allow them to push the water downwards, creating swirling vortices that carry momentum beneath the surface of the water. Hu and his colleagues found that it was the rearward motion of these vortices and not the surface waves (which others had suggested) that propels the insect forward.
One must wonder how long it took this creature to “evolve” this complex mechanism for movement, and how many drowned while it was being perfected. Additionally, why haven’t other insects adopted similar means of locomotion? It is among the smallest of creatures, yet it still baffles the brightest scientists. These amazing animals (like so many others) could not have survived years of transitional evolution. Rather, the same Creator Who walked on water while He was on the Earth, intelligently designed them with this unique rowing ability.
Hu, David L., Brian Chan, and John W.M. Bush (2003), “The Hydrodynamics of Water Strider Locomotion,” Nature, 424:663-666, August 7.