Show Me Some Science! One Hundred Toy Cars
We got 100 tumble buggies together to see how much we can pull. A tumble buggy is a toy car with rather grippy tires. Because of this high coefficient of friction, it can pull with a significant fraction of its own weight. Though each buggy weighs less than a pound (0.5 kilogram), if you get enough of them together, you can slide someone across the floor or pull a nail out of a board!