I've been pondering this double-slit experiment thing - when electrons aren't observed, they seem to act like waves passing through both slits simultaneously. But the moment we measure them, they behave as particles? What's really happening there?

I've been pondering this double-slit experiment thing - when electrons aren't observed, they seem to act like waves passing through both slits simultaneously. But the moment we measure them, they behave as particles? What's really happening there?