Kelly Doudna is an author of non-fiction children's books. Some of her titles include It's a Baby African Elephant!, It's a Baby Baboon!, It's a Baby Cheetah!, and It's a Baby Chimpanzee!. She also writes books in the Super Simple Science and the Super Simple series.
They help make work easier, like when you need to lift something heavy or reach way up high. Some machines are so simple that you might not think of them as machines. There are six simple machines: the lever, the wheel and axle, the pulley, the ramp, the wedge, and the screw.
Can you adjust a seesaw to lift an elephant? What happens when you combine two or more simple machines? Read and find out!