Meg Lowman was always fascinated by the natural world above her head—the colors, the branches, and, most of all, the leaves and mysterious organisms living there. Meg set out to climb up and investigate the rain forest tree canopies—and to be the first scientist to do so. But she encountered challenge after challenge. Male teachers would not let her into their classrooms, the high canopy was difficult to get to, and worst of all, people were logging and clearing the forests. Meg never gave up or gave in. 

You know the Super Soaker. It's one of the top 20 toys of all time. And it was an accidental discovery that brought it into being. Trying to create a new cooling system for refrigerators and air conditioners, inventor Lonnie Johnson instead created the mechanics for the iconic toy. A love of rockets, robots, and inventions and a mind for creativity were present in Lonnie Johnson's early life.

Plastic bags are cheap and easy to use. But what happens when a bag breaks or is no longer needed? In Njau, Gambia, people simply dropped the bags and went on their way. One plastic bag became two. Then 10. Then a hundred. The bags accumulated in ugly heaps alongside roads. Water pooled in them, bringing mosquitoes and disease. Some bags were burned, leaving behind a terrible smell. Some were buried, but they strangled gardens. They killed livestock that tried to eat them. Something had to change.

When a terrible drought struck William Kamkwamba's tiny village in Malawi, his family lost all of the season's crops, leaving them with nothing to eat and nothing to sell. William began to explore science books in his village library, looking for a solution. There, he came up with the idea that would change his family's life forever: he could build a windmill. Made out of scrap metal and old bicycle parts, William's windmill brought electricity to his home and helped his family pump the water they needed to farm the land.

Growing up in the 1920s on a dirt-poor farm in North Dakota, Mary Sherman's life was filled with chores—until she finally began school and discovered she loved to learn. Mary excelled at science, especially chemistry, and leaped at the chance to work in a laboratory during World War II designing rocket fuels. And when the US decided to enter the space race, Mary was chosen over her male colleagues to create the fuel to launch a rocket carrying America's first satellite.