Carbonated Drink Shake Up

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Gases, Kitchen Chemistry, Pressure and Fluids

Alternative titles: Soda Can Shake-Up

Summary

This demonstration explores what happens when a shaken soda can is opened. Shaking introduces bubbles that cling to the can’s inner surface. Opening the can releases pressure, causing these bubbles to expand and force liquid out in a foamy burst. By snapping the sides of the can before opening, bubbles are dislodged and float to the top, reducing the mess.

Procedure

Take a sealed can of soda and shake it vigorously.
Open the can immediately over a sink or pan and observe the spray of foam.
Shake another sealed can, but this time flick or snap the sides of the can firmly with your finger while rotating it several times.
Open the can slowly and observe the difference in foaming.
Repeat the experiment with diet soda and note whether the same tapping method prevents foaming.

Links

Soda Can Shake-Up - Sick Science!:

📄 Soda Can Shake-Up - Steve Spangler: https://stevespangler.com/experiments/soda-can-shake-up-experiment/

Variations

Test different soda brands or flavors to compare foaming effects.
Try the experiment with bottles instead of cans.
Investigate how temperature affects foaming (cold vs. room temperature soda).
Compare results of tapping the top of the can versus snapping the sides.

Safety Precautions

Open shaken cans only over a sink, tray, or outdoors to avoid mess.
Clean up spills immediately to prevent sticky surfaces.
Do not shake cans near electronics or important materials.

Questions to Consider

Why does shaking a can cause soda to spray when opened? (Shaking creates nucleation sites where carbon dioxide bubbles form; when the can is opened, the bubbles expand rapidly and push liquid out.)
Why does snapping the sides of the can reduce spraying? (It dislodges bubbles from the walls, allowing them to rise to the top where they can escape without carrying liquid.)
Why do diet sodas behave differently? (They may contain more dissolved CO2 or unique interactions between sweeteners, preservatives, and water.)
How does Boyle’s Law relate to this experiment? (When pressure decreases upon opening, gas volume increases, forcing bubbles to expand.)