At a similar age I did a "science project" to see if the big floppies or the small one were better at reading data after being stuck to a fridge with a magnet for a month, and similar with sticking them in a freezer.

Every single disk had zero errors.

You need a moving magnetic field to destroy the data unless you have a very very strong magnetic.

Yep, and temperature doesn't really have an effect on magnets (perhaps at very low or when the disk melts).

I do recall that most of the teachers and students thought it was "most surprising outcome" or something like that, from years of "if you put a magnet near your computer or disk it will eat the world" propaganda.