The first coin authorized by the new United States Congress was a one-cent coin. Because there was not yet a government mint, more than one version of the coin was struck. The design (believed to be suggested by Franklin) shows the sun and a sundial on the obverse, with the words FUGIO and the date 1787. Centered on the reverse is the motto WE ARE ONE, surrounded by the words UNITED STATES and ringed by a chain with 13 links.
The 1943 steel cent, also known as a steelie, was a variety of the U.S. one-cent coin which was struck in steel due to wartime shortages of copper. Due to wartime needs of copper for use in ammunition and other military equipment during World War II, the US Mint researched various ways to limit dependence and meet conservation goals on copper usage.
When the price of copper rose in 1982, the mint was forced to make a midyear change from solid bronze (about 97% copper) to copper-plated zinc. You can find cents dated 1982 made out of both metals. The only way to reliably tell them apart is to weigh them on a sensitive scale. Copper cents weigh 3.11 gm, zinc ones are 2.5 gm. The last copper penny was minted in Denver on October 22, 1982.