An electron is so tiny that we can't see it, even with the best microscopes. If you check out the article What is an elementary particle?, you'll learn that an electron isn’t made of smaller pieces — it’s one of the smallest building blocks of everything, called an elementary particle.
In Book 8, Millie tries to break an electron, but guess what? She couldn’t!
So far, nobody has been able to split an electron. But who knows? Maybe someone will discover how one day! In the article Elementary particles, you’ll read how ancient Greek philosophers thought atoms couldn’t be split. That idea stayed around until the 20th century, when scientists found out it wasn’t true.
