Shaken Soda Can Race

When two identical soda cans roll down an incline, the unshaken can reaches the bottom first. Shaking one can creates foam and bubbles that change the distribution of mass inside, altering its moment of inertia and causing more energy transfer to the fluid. This reduces the shaken can’s rolling speed.

1. Place two identical unopened soda cans at the top of a smooth incline.
2. Shake one of the cans vigorously for several seconds to generate foam inside.
3. Release both cans at the same time and observe which one reaches the bottom first.
4. Repeat the test to confirm results.
5. Discuss how the foam and bubbles inside the shaken can influence its motion.

The Shaken-Soda Cans experiment - Kids Fun Science:

Which Can of Beer Has Been Shaken - Chemistry Europe: https://www.chemistryviews.org/details/video/11159200/Which_Can_of_Beer_Has_Been_Shaken/

• Test cans at different temperatures (cold vs. room temperature) to see if foam formation changes.
• Compare the race results with other carbonated beverages (sparkling water, seltzer).

• Perform the experiment on a stable incline free from obstacles.
• Do not open the shaken can immediately after rolling to avoid spraying soda.
• Clean up any spills from leaks to prevent slipping hazards.

• Why does the unshaken can roll faster? (Because its contents remain mostly liquid, giving it a different moment of inertia compared to the shaken can with foam.)
• How does foam affect energy transfer inside the can? (Foam distributes unevenly, causing more energy to be absorbed by the fluid rather than translating into motion.)
• What role does density play in this experiment? (Liquid is denser than foam, so the unshaken can has more compact mass distribution, rolling more efficiently.)
• How does this demonstration connect to the concept of moment of inertia? (The shaken can’s altered mass distribution increases its effective moment of inertia, slowing it down.)