How does a videotape work?
A videotape is pretty complex for something that is mass produced and costs about 2 bucks each. It features an outer shell, a moving spring-loaded door to protect the tape, two spools, an 800-foot long, 1/2-inch wide piece of oxide-coated mylar tape, several low-friction rollers to guide the tape, and two spring-loaded locks to keep the tape from unrolling inside the cassette. When the tape is loaded into a VCR, the VCR uses a lever to release and open the spring-loaded door, exposing the tape. It also inserts a pin into the hole to disengage the two locks on the spools so the drive can extract the tape and play it.
