This is SCIENCE FRIDAY. I'm Ira Flatow. Imagine stepping onto the Earth two billion years ago, taking a stroll along the shores of an ancient beach near the northern edge of what today is Lake Superior. You wouldn't see any trees. They didn't hit the scene until, oh, another billion-and-a-half years. What you might see, though, if you had a microscope, were tiny bacteria-like organisms on the shore having a ball eating each other.
A smartphone can tell you where to get a cup of coffee, but it can't go get the coffee for you. Engineers would like to build little machines that can do stuff. They would be useful for a lot more than coffee, if we could figure out how to make them work.
But the rules of mechanics change at small scales. Friction becomes dominant; turbulence can upend a small airplane.