A resistor is simple and cheap. Chop one open with diagonal cutters to see if you can find the carbon that does the resisting.
Various resistors scraped open to see how they have been made. sparkfun 
Learn by taking things apart, even if you have to destroy them in the process.
My first step into electronics was watching my brother dissect resistors with a high school friend up the street.
A transistor is a variable resistor controlled by electrical properties, possibly those of another transistor. The compounding of transistors made possible small, portable radios changing music listening forever.
A transistor circuit is harder to take apart than a resistor but it can be done.
Ken Shirriff reverse engineers old and popular integrated circuits by disassembling the chips themselves. blog