Every student of physics is familiar with Faraday's Law of Induction. However, many of them might not realize that induction can also be variable. This means that the current induced into a circuit is constantly changing. This effect is most notable for it's use in RF transmitters.

Use this well-built set to study the phenomenon. Using the hand crank, slide a steel core in and out of a copper coil to induce varying amounts of current.

Variable Inductance apparatus are unusual and hard to find pieces for the physics lab.