Context: Bell worked extensively in medical research and invented techniques for teaching speech to the deaf. During his Volta Laboratory period, Bell and his associates considered impressing a magnetic field on a record as a means of reproducing sound. Although the trio briefly experimented with the concept, they could not develop a workable prototype. They abandoned the idea, never realizing they had glimpsed a basic principle which would one day find its application in the tape recorder, the hard disc and floppy disc drive and other magnetic media.

Question: What famous lab did Bell spend time working for?
Answer: Volta

Question: What type of energy did Bell investigate at the Volta Laboratory?
Answer: magnetic

Question: The magnetic field is part of what sort of recorder?
Answer: tape recorder