I’ve enjoyed working through the Learning Arduino tutorials, and I’ve learned quite a lot. But I have to say, Episode #1 is TERRIBLE.
For starters, voltage is not a “speed” – it’s a FORCE, as in Electromotive Force (EMF). Second, Stephan shows streams of electrons of various strengths (currents) but never says WHY one stream is flowing faster than another.
The difference, of course, is RESISTANCE, something he never mentions in the video.
A much better analogy is the one about water flowing through a pipe. Voltage is analogous to pressure, current to flow rate. Resistance is determined by the diameter of the pipe (or perhaps a restriction, like a valve that can be adjusted.
Please consider re-doing this one video. The others are all so good, it’s a shame #1 is so bad.