The reason it's smarter to store your eggs with the fat end up is that the egg itself does not completely fill the interior of the shell.
Today on A Moment of Science, another take on sibling rivalry. Sibling rivalry among sharks, that is.
Let’s say you hard-boiled some eggs last night to make egg salad. But today, when you open the fridge, you discover that a helpful family member has put them right back in the carton along with the raw ones. Without cracking the eggs open, how can you figure out which is which?