Ubuntu isn't the distro to choose for educational purposes. Sure, it's a good, stable, and clean way to enjoy desktop computing. However, I wouldn't consider it a production/server kind of distro or something that involves work. They are the kind of distros that you will learn with.

If you want to play with Ubuntu, install it to your system without a GUI. That will get you started. You will get to know aptitude very well since you will need to install the window manager of your choice, as well as software packages.

Or pick something a little more challenging like Arch Linux, etc. There's hundreds of distributions to pick from, honestly. Pick up a book on Slackware, Gentoo, and FreeBSD. That'll get you started.