Sperm Cell Facts: Lesson for Kids

The head of the sperm is about five micrometers long and three micrometers wide. A micrometer is too small for the human eye to see. The tiniest speck of dust sitting on your desk is about 50 micrometers. So sperm are small. In fact, they're microscopic.

The next part of the sperm is called the midpiece. The midpiece is a section of the sperm that contains the sperm's fuel. There's not actual gas in this part, but rather special structures, called mitochondria. These mitochondria help to generate the enormous amounts of energy needed to move the sperm's tail.

At the other end of the sperm is the flagellum, which is a tail-like structure measuring about 50 micrometers in length. The flagellum whips back and forth pushing the sperm closer to the egg. It's the same physical movement you've probably done in a pool, keeping your legs close together and kicking hard to propel yourself forward. The flagellum allows the sperm to be a powerful swimmer, often fighting against the current.