pH is a big deal in biology. But it can be dull and hopelessly abstract when the focus is the formula. The experiments below are designed to allow students to experience the reality of the "pouvoir d' hydrogen" (power of hydrogen; a handy mnemonic for pH, and actually the root of the abbreviation!). The 'red cabbage indicator' is an easy to make solution (basically cabbage + water + blender) that shows delightful colors and can be used to indicate a huge pH range. 'Miraculous lemonade' combines a pH-influenced protein (miraculin) with lemons. Lemons are nasty-bitter on their own, but abundant protons (H+; acidic pH) tweaks miraculin sitting on taste receptors to 'sense' sugar--making no-cal lemonade right in your mouth!

pH is often critical in biology, from amplifying hemoglobin's "bind in the lungs/release in the tissues" O2 behavior to the flu virus' clever 'Trojan horse' strategy.