Science Buddies: "Ask an Expert"

Hello! I am doing the chills and thrills of roller coaster hills experiment. I was wondering what size rubber stopper you would recommend for the 2"by 18" tube. I think that the #10 tube on the website that's on the materials part of the experiment page.
Thanks!

Hi JUBLiA,

You're working on this project, correct?
https://www.sciencebuddies.org/science- ... p041.shtml

The rubber stopper needs to wide enough to completely block the end of the plastic tube. It looks like a #10 stopper would probably work.