The simulation on this page is inspired by question 8 of the annual Dutch national science quiz of the year 2000. The question was:

You have got two cylinders. They have equal size and weight. One cylinder is solid and made of wood, the other is hollow and made of iron. You roll both of a slightly inclined plane. Which of the two cylinders is down first?
You can see for yourself which cylinder arives first. The following links give some theoretical background information. Laboratory