Put your engineering skills to the test to see if you can build a machine—powered by nothing but gravity—that will automatically sort out two different sizes of plastic spheres. That might seem like a strange task, but have you ever used a coin sorter to separate pennies, nickels, dimes, and quarters? How about using a sifter in the kitchen to separate fine grains of flour or sugar from bigger lumps? Machines that can automatically sort objects or particles of different sizes are… Read more