Why Does Shaken Soda Fizz?
Learners can explain why a shaken soda bottle fizzes violently: the shaking did not create new gas, it provided nucleation sites that let already-dissolved CO2 escape all at once.
A complete interactive classroom, not just a preview.
Start when you are ready to enter this Stage's 11 scenes and explore, respond, and learn as you go.
Why does a shaken soda bottle explode when opened, while a still one only hisses?
- dissolved-co2-equilibrium
- CO2 exists in soda in a balance between gas above the liquid and dissolved gas molecules in the liquid.
- pressure-and-solubility
- More pressure above a liquid lets more gas stay dissolved in it.
- nucleation-sites
- Tiny imperfections, fibers, or rough surfaces give bubbles a place to start growing.
- supersaturation
- When pressure suddenly drops, dissolved gas is temporarily above its new equilibrium and wants to leave the liquid.
- shaking-reveals-not-creates
- Shaking moves dissolved gas onto nucleation surfaces as many tiny bubbles; opening then releases them together.
Shaking a soda bottle creates new gas that wasn't there before.
Show that the CO2 was already dissolved; shaking only redistributes it into many bubbles clinging to nucleation sites, which then all escape at once when the cap comes off.
A smooth glass bottle should fizz less than a plastic bottle because it has no rough surfaces.
Show that any container's inner surface has microscopic imperfections that can act as nucleation sites, though smoother surfaces and stillness delay bubble growth.
Tiny bubbles rise through the liquid because they are lighter than air.
Establish that buoyancy drives bubble rise because the gas inside is far less dense than the surrounding liquid, not because the gas itself is 'lighter than air'.
- concept of gases dissolved in liquids
- basic idea that pressure affects dissolving
- familiarity with opening a soda bottle
- quantitative Henry's law constants
- thermodynamic derivations
- detailed nucleation theory mathematics
- industrial carbonation processes
- other gases besides CO2
- Learner can state whether shaking a sealed soda adds new gas to the bottle, and justify the answer with the concept of dissolved CO2 equilibrium.
- Learner can name at least two conditions (e.g., rough surface, sugar grain, tap on the side) that trigger bubble release and explain why.
- Learner can transfer the explanation to another carbonated or supersaturated drink (e.g., why tapping the side of a beer bottle calms it, why mentos + diet coke erupts).
- Apply the nucleation + dissolved-gas-equilibrium model to explain why tapping the side of a carbonated drink can calm it down, and why dropping a rough object (like a mentos) into soda causes a rapid eruption — recognizing where the same model fits and where it would be oversimplified.
Curious general learners aged 13+ with basic middle-school science literacy but no chemistry background. They can read simple diagrams and follow cause-and-effect chains.
- 01A Familiar Explosionslide
- 02Predict: What Did Shaking Add?slide
- 03CO2 Is Already Inside the Sodaslide
- 04Pressure & Solubility Simulatorinteractive
- 05Bubbles Need a Place to Startslide
- 06Nucleation Labinteractive
- 07Shaking: Distribute, Don't Createslide
- 08Shaken vs. Still: Side by Sideinteractive
- 09Why Bubbles Riseinteractive
- 10Mentors vs. Tapping: The Transfer Challengeinteractive
- 11A Cleaner Glass and a Harder Questionslide
Discussion threads for a Stage aren't available yet.
