Magnetic Storage. Piano wire, an electromagnet and a microphone. This was all the Danish inventor Valdemar Poulsen (1869-1942) needed in 1898 to create the telegraphone or wire recorder â the first known device capable of recording sound magnetically.agnetic Storage. Piano wire, an electromagnet and a microphone. This was all the Danish inventor Valdemar Poulsen (1869-1942) needed in 1898 to create the telegraphone or wire recorder â the first known device capable of recording sound magnetically.
And as of 2016, there are about 2.3 million home-schooled students in the United States (Brian, 2016). The studies found that of these children, 83 percent were White, 5 percent were Black, 7 percent were Hispanic, and 2 percent were Asian or Pacific Islander.
This is up from one estimate that there were about 2 million children (in grades K to 12) home educated during the spring of 2010 in the United States (Ray, 2011). It appears the homeschool population is continuing to grow (at an estimated 2% to 8% per annum over the past few years).