Mechanics:
Racing Soup

PIRA Class: 1Q10.50

Purpose:
A surprising result that hinges on moment of inertia and what is and is not rotating while a can rolls.

Description:
A can of beef broth (337 g) and a can of cream of mushroom soup (351 g) are rolled down an incline in a race. The broth will win easily.

PEDAGOGY: After the race, hand both cans to a student to shake and ask them what they hear. They will hear the broth slosh and hear nothing from the soup which can open a discussion about what happens inside as the cans roll.

The viscosity of the cream soup means that the can contents rotate with the can as if it was a solid rod. The broth is able to "slide" or "slosh" inside the can allowing the can to rotate like a ring around the soup.

Equipment:
Cans of broth and cream soup, wooden board for the incline and books to raise the incline

Location:
Shelf 144 (cans are inside the moment of inertia bin), wood for the incline is in the back right corner of the demo room, books are available next to the desk in the demo room