Kids’ science questions no. 4.

sh know when it’s bedtime? Written by Dr Bryan Hatton Posted in Uncategorized Comments Leave a comment Letterbox Lab is a science subscription box coming soon to UK families. We answer tough questions that children love to ask. This week, how do fish know when it's bedtime? ​It seems our previous post asking why the sea is salty inspired some further curiosity and we’ve been asked how fish know when it’s time to go to sleep! What a great question, we’ve had a lot of fun pondering the answer.