Video narration
Why does lemon juice fizz when you mix it with baking soda? That familiar reaction shows acids and bases changing each other. Acids taste sour and release hydrogen ions in water; they react with baking soda. Bases are often associated with a slippery feel and produce hydroxide ions, helping counter acids. On pH's continuous scale, acids fall below seven, neutral solutions are at seven, and bases rise above seven. Lower numbers mean more acidic; higher numbers, more basic. But pH is more than a label: it shows how acid and base particles are changing each other. This is neutralization: their reaction makes the solution less acidic and less basic. With lemon juice or vinegar and baking soda, it also forms salt, water, and carbon dioxide gas-the fizz. So why the fizz? The acid and base react and neutralize; pH tells you whether the result is acidic, neutral, or basic.