Tape is fast and easy to use but very unstable and easy to remove/move.
The building of the track had to be very precise in order for the marble to go through at the right speed.
I am very satisfied with the progress we've made from nothing to a nice physics example.
The fact that the roller coaster worked at some points and didn't at others drived me nuts. Its instability is very frustruating.
Realizing how the rules and theory are accurate and true have been the best experiences during this project. I love it when it works!