Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com. Why are there seven days in a week? – Henry E., ...

Waiting for the weekend can often seem unbearable, a whole seven days between Saturdays. Having seven days in a week has been the case for a very long time, and so people don’t often stop to ask why.