Book 7 in which the electrons invite Millie to a party and she is shocked by antimatter is very special: most of the questions Millie asks the electrons in this book were suggested by children who read the previous stories. Here is what they wanted to know:

Do electrons have mums and dads? How are they born? How old are they? How long do they live for? Do they grow up?

As well as answering these questions, the electrons introduce Millie to static electricity, radioactivity and antimatter. Many thanks to Danielle, Josh, Mia, Tamzin and Tylah from Raumati Beach School, New Zealand, for helping Millie in this adventure.