When I was growing up one of my favorite insects to observe was the water strider (it still is). It was entrancing to watch this creature skate around on the surface of the water. “How does it do that?” I wondered. Now I know (well, at least, the very basic reasons). It uses the high surface tension of water and distributes its weight via its long spindly legs (phys.org). The tarsi or the “feet” of the insect are also covered with water-repellent hairs that help keep the insect on top of the water. If the tarsi become wet in choppy water, the insect can no longer stay on the surface of the water and must get to a solid surface to dry out; thus, you normally find these insects on calm, quiet water (An Introduction to the Study of Insects by Borror, Triplehorn, Johnson). Well, I must not be the only one who is fascinated by this insect because Stephan Froden took the time to actually design and build his own water strider out of Technic LEGO. He entered the 2012 Eurobrick’s “To Sail the Technic Sea” contest and won. This LEGO insect even walks on water.
The following is a little information about some of the things he used to make this model a reality (from Eurobricks forum):
I ended up using an [LEGO] M-Motor for propulsion, but the battery box is external and uses a tether to control the water strider. There is no steering in this model.
The mechanism that moves the middle and rear legs uses a modified version of Sariel’s Octopod mechanism. The middle legs move in an elliptical motion, and have rubber tips to give them grip and help my water strider move forward when it is ‘on land’. When my water strider is in the water, the rubber tips are replaced with 6×6 radar dishes that act as paddles or oars.
To get my water strider to float in water I used the hemispheres from the Death Star Planet set. The hole in the top can be blocked using a 1×1 round plate, and this provided enough floatation to stop my water strider from sinking when it isn’t moving.
Unfortunately when my water strider is moving, or when the water is a bit choppy, the hemispheres on the rear legs flood and sink, so I had to use some ping pong balls for a little bit more floatation… I would have used the balls from the Mindstorms sets if I had any of them.
Here is his water strider in action (awesome):
And here is the live insect in action (Richard Hammond’s Invisible Worlds – Water Strider – so awesome!):
You can find a list of links from Stephan Froden that provide all the details about this project on Flickr.