In 1982, the composition of a penny changed from 95% copper and 5% zinc to 95% zinc and 5% copper. Compare the relative densities of a penny that was made in 1981 to a penny made in 1995.

How long could you survive without electricity? what parts of your life would be affected by loss of electricity? should you prepare for an electricity outage, and if so, how would you prepare? what backup system could your family or community install to generate limited amounts of electricity during an outage? how does this system create an electric force field and generate electric current?