This should be listed in the Wiki..
if you go to raspberrypi.org there you will find a HUGE wealth of very high quality stuff all relevant to learning electronics and computing fundamentals on the Raspberry Pi platform which in case you've been dead the last few years, started out a mere five years ago as a project to make a credit card sized computer that cost $35 for everybody.
Well, THEY SUCCEEDED and now its five years later and they have sold millions of them and its incredibly useful device for everybody and their most recent one, the Raspberry Pi 3 Model B actually is more powerful than many laptops and tablets are today. And its still $35.
When you get there, go to "MagPi" their own magazine, which is quite professionally done, and there you'll find a wealth of download-able material.
Their magazine is basically educational project ideas geared towards everybody from smart teenagers to kids, with content so good it will likely also appeal to scientists and engineers, actually pretty much EVERY KIND OF PERSON who frequents this unique community will find something useful there. "I guarantee it!"
...everything from free BOOKs on Bash scripting and beginning C programming for beginners, to four huge PDF "project books" each containing dozens of projects, using the Raspberry Pi hardware family (some of which cost as little as $5 or $10 now). And they all involve either electronics or programming.
In addition to these books, there are more than 50 issues of their magazine which is chock full of even more cool Linux stuff to do - some of which you can ALSO do with various kinds of modification or not on Ubuntu or Mint, (or even RedHat's based pidora or fedora!) one way or another. Theres also a bunch of other stuff thats also free, for example some books specifically for teachers. Its really quite a high quality effort, very little elsewhere on this rapidly shrinking planet is even remotely comparable.
MagPi is a jewel .
https://www.raspberrypi.org/magpi-issues/?C=N;O=A