Most of you guys here are aviation fans, so this video is probably not for you. We felt like we needed to do it however, because we can't tell you how many times we were asked in posts and pictures about "those things."
We're talking of course, about winglets.
These tiny upward extensions of the wings are used on many planes. From Boeing's commercial planes to military transport, all planes can use them for one reason. To increase fuel efficiency.
Although the intitial concept was developed in 1897, the first credited winglet-like device was alloted to the German Messerschmitt Me 163.
The video below will tell you, in a short time, how winglets accomplish that. It's really not that difficult to understand (the concept), but a lot of forces are at play here.
Planes can fly due to lift. There is negative and positive pressure acting on the wings, but at the tips you have a spill over. Winglets help counteract that.
Check out the video to see exactly how it all works. It's very informative and maybe, when asked, you'll shine one day with the answer.