The carousel represents the electron cloud, with the child as the nucleus. Attaching a bar magnet to the child be like the nuclear magnetic moment, generating a dipole field as the carousel spins, like the spin dipolar contribution. Holding an electrically charged ball simulates the Fermi contact interaction, where electron density overlaps with the nucleus. A magnetometer placed nearby would detect these effects, just like how experiments measure hyperfine interactions in atoms or solids.