Science Buddies: "Ask an Expert"

About how many pennies do I need to test the bridges? I will have 13 groups so I want to make sure I have enough materials on hand.

Thanks!

ekward,

Thank you for the question and welcome to the forum. The amount of weight will depend on the materials you use (cheep straws, etc...) and how well they are constructed. So I would expect results to vary from bridge to bridge. However, when I did this experiment, my stronger suspension bridge averaged 200 pennies before collapsing. The directions suggest having at least 350 for each experiment, so you'd need 4,550 pennies for 13 groups. If this is to much, you can use something heavier, like quarters, which should cut down the number of coins needed per group to around 150 each.