Penny Weight Presentation

In our group presentation we told that a penny's weight depends on the year it was minted and its composition different years of pennies have different ratios of metals, like zinc, copper, and nickel as well as alloy metals, bronze, steel, and brass .  Its condition is also a factor, corrosion, tarnish, scratches, and foreign material.  A random penny's mass is 2.5g and its weight is .00551 lbs or .0245 N.  A 1973 penny weighed 13.48g or .02972 lbs, that's five times more than a penny from any year!  Pennies minted in 1908 weigh 3.11g or .00686 lbs.