Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

The Sciences

How to Walk on Water

By Fenella SaundersNovember 10, 2003 6:00 AM

Newsletter

Sign up for our email newsletter for the latest science news

rdstrider.jpg

Courtesy of David Hu/MIT

Water-striding insects skim across the surface of a pond with no effort at all, but a team of MIT mathematicians had to work hard to figure out how they do it. John Bush and his graduate student David Hu set up vats of dyed water and high-speed video cameras to catch the striders in action. Using this setup, Bush and Hu could see that they row with their center legs, even though surface tension keeps the insects from dipping into the water. “It’s sort of like the breaststroke, but they don’t break the surface. When they push down on the water, they create a small valley, called a meniscus, and that acts like an oar,” Hu says. The middle legs press against the back wall of the meniscus, pushing the insect forward and transferring momentum to a series of vortices in the water (see below). To prove this result, MIT mechanical-engineering graduate student Brian Chan built a four-inch-long robot that uses the same technique. It water-walked successfully, if not quite as elegantly as its living counterpart.

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.

    Subscribe

    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%

    Subscribe

    Already a subscriber? Register or Log In