It depends on the pennies You used. Some 1982 and newer are made of copper/zink. They weigh 2.5(.10 tolerance). Some 1982 and older are made of copper/brass. They weigh 3.11(.15 tolerance).I used a 12 inch ruler. Two 3 inch square cardboard. Pencil. Tape. Penny’s On average a penny weighs 2.5 grams ...to equally balance I used 5 penny’s,,,,the total I got is 12.5 grams..It’s not perfect but I think it’s close
It may not be the best but it just shows a different method of trying to accomplish something..I wish someone in my family would have taught me different methods on how things work and helping me develop better skills in my younger days.Bill,that is ingenious,brilliant even.A principle that goes back thousands of years and still works and works well.Good going my friend and great teaching your granddaughter.
What part of MB are you, I call Sandy Lake my home.Oh yeah you’re in NY, forgot you guys get snow. We also got our first snow fall here in MB Can.