How Magnets Create Sound In Electric Guitars

Dr. Henry Reich of MinutePhysics tested out a magnetic guitar pick that was sent to him to review. While doing so, Reich scientifically broke down the physics behind electric guitars, explaining the anatomy of the instrument and how magnets work to create different forms of sound on both the inside and outside of the guitar.

I was sent a magnetic guitar pick to review, so I reviewed it. Does it work? How? Why? What's the physics of electric guitar strings and pickups? Are magnets useful? Do they affect the strings? The pickups?