Today in Issues for Science Professionals, APSC-311 class we were asked a very simple question how much does a penny weigh? At first glance this looks like a very simple question and could be answered very quickly by replying 2.5 grams approximately. However, Dr. Schultz asked the full question like this, "It is Saturday morning 9 am, and I walk by acoustic café, and I look on the side walk and there is a penny there I pick up the penn,y how much does it weigh?" and knowing him there was a reason why he asked it like this. My answer is I do not have enough information to give the proper answer. First of all it depends on the date. After doing some research I found that the Indian Head pennies dated 1864 to 1909 weigh 3.11 grams. The Lincoln, Wheat Ears Reverse penny weighs 3.11 grams except for steel cents made only in 1943 that weigh 2.67 grams. The Lincoln, Memorial Reverse penny (1959 to mid 1982) weighs 3.11 grams.The Lincoln, Memorial Reverse penny (mid 1982 to present) weighs 2.5 grams. Secondly, is the penny clean and is perfect condition, Or is there gum stuck to it or has it gone through a lawn mower and has part of it missing.