If you have access to an old car (pre-computer), buy a tune-up kit for it - and bury it.
Points, plugs, condenser, coil, wires, battery - assuming a mechanical fuel pump.
Although I did once make a coil wire out of a coathanger - it was just out of necessity, I assure you.
I can and have built crystal radios with a chunk of galena, an empty cigarette pack, a sheet of newspaper, a toilet paper roll and a bunch of wire.
It's good for cooks to know the basics of technology, and how to build them from scratch. You just never know what might happen in a commercial kitchen.
/johnny