system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do non-radio objects (eg fans, bed frames) pick up and play AM signals?
gpt
They have metal parts in them that can act like an antenna. If exposed to a strong enough electromagnetic field, they'll begin to oscillate at whatever frequency that field's at. This is essentially how a crystal radio works. 

But you'd need to be really close to a really, really powerful transmitter to hear music on your bedframe or water pipes. The origins of this story seem to date back to the 1930s when WLW in Cincinnati opened up a 500kW transmitter. The FCC no longer allows transmitters that powerful. They max out at 50kW nowadays, and they usually aren't built close to residential areas.