English: Illustration of a spin in a Bloch sphere showing a) precession in the laboratory frame due to a static magnetic field followed by b) the usefulness of considering this in a rotating frame and finally c) the magnetic resonance effect due to a resonantly oscillating magnetic field. This animation was made by Gavin W Morley with POV-Ray and Photoshop
A spin is shown precessing about a static magnetic field in the lab frame, then being still in the rotating frame, and finally precessing about a resonant magnetic field in the rotating frame.