Inside the fizz.
A bottle of water. A pull of a lever.
Explore the chemistry behind the fizz ↓
The guided explanation below also works without 3D.
Reference-based exterior · illustrative internals
What makes water sparkle?
Explore the gas you can’t see, the bubbles you can, and the small reaction that makes water acidic.
Higher pressure. More dissolved gas.
CO₂ molecules move between gas and water. At equilibrium, increasing CO₂ pressure increases the amount dissolved. Cooling the water also increases its capacity to hold CO₂.
Scrub the loss of dissolved gas. This is a progress model, not a clock; real degassing depends on nucleation sites, agitation and the vessel.
Most dissolved CO₂ stays as CO₂(aq). A small fraction reacts with water to form carbonic acid. Dissolving and reacting are different processes.
Molecule models show atom connectivity; proportions are not species abundances. Actual pH also depends on the water’s minerals and buffering.
Ideal-water equilibrium estimate. These pressure values are model inputs, not ART settings or a conversion from lever presses.
How the chemistry model works
Henry’s law: c = kH(T) × pCO₂. We use kH(25 °C) = 0.035 mol/(kg·bar), a temperature coefficient of 2400 K, and a CO₂ molar mass of 44.0095 g/mol from NIST Chemistry WebBook. Temperature uses kelvin in kH(T) = 0.035 exp[2400(1/T − 1/298.15)]. This approximate model treats gas as ideal and estimates dissolved molecular CO₂, not all dissolved inorganic carbon.
In the opening chapter, the liquid starts at the selected equilibrium concentration and approaches an air-equilibrium target using c(s) = cair + (cinitial − cair)(1 − s). The slider s is a fraction of the change, not elapsed time. The model assumes well-mixed air with a fixed CO₂ partial pressure of 0.00042 bar; it does not solve transient headspace mixing. Total atmospheric pressure remains about 1 bar.
Physical background: OpenStax on gas solubility. Reaction background: Wang et al., CO₂ hydration and dehydration in water and ACS on dissolved CO₂ and carbonic acid. The acidity view uses qualitative reactions, not a pH calculation.