EVER WONDER ABOUT THESE? WELL, THEIR PURPOSE IS EXTREMELY USEFUL
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.