Here comes the electronics lab:

A multimeter checking voltage on a breadboard

3.2: The voltage regulator worked fine, delivering a steady 5.00 volts. (For the record, my 9 volt AC adapter was also measured a weirdly accurate 9.00.)

Testing a switch attached to a breadboard

3.3: Switch worked fine.

A switch and three LEDs attached to a breadboardFour LEDs attached to a breadboard

3.4: In series, the voltage dropped evenly from LED to LED. Up to 3 red LEDs would light but a 4th killed it.

Three illuminated LEDs on a breadboard

3.5: In parallel, the amperage across the circuit (between the last LED and ground) was 14 milliamps.

Checking voltage across a resistor on a breadboard

3.6: The potentiometer worked as expected. (At first, I accidentally plugging both ends of the pot into power — this turned the curve of voltage from the potentiometer into a dip — it was high at either extreme, and lowest (but not 0) at the center. Might be a useful behavior for future applications.)