What happens when you bet a group of friends they can’t build a roller coaster in their backyard ... assorted nails and screws, some caster wheels and a folding seat from an old arena.

Narrator: So what can engineers do to protect riders as they continue to build taller ... through the roller coaster and you lose speed due to air resistance and drag in the wheels, your speed ...

Have you made a backyard roller coaster, or are thinking about building ... The video below contains a time lapse of the steel wheel build ...