Follow nitrogen from a shovel of compost (or a fert granule) all the way into a root cell. Play the story, pull a lever — and when you reach the root, tap the glowing spot to zoom into the doorway itself and watch the plant pull nutrients across its skin.
ZOOM: ~1 mm · a pinch of soil
No sound? On iPhone, flip the silent switch off (side of the phone) and turn the volume up — Safari mutes audio when it's on.
NH₄⁺
Ammonium. One nitrogen + four hydrogen. Carries a + (positive) charge, so it sticks to clay.
NO₃⁻
Nitrate. One nitrogen + three oxygen. Carries a − (negative) charge, so clay repels it and it washes away.
H⁺
Proton. A hydrogen ion. The root pumps these out to build the "current" that powers uptake.
ATP
Energy. The cell's battery. Feeding isn't free — the plant spends ATP to pull nutrients in.
Do something — watch the soil react
Both organic and synthetic nitrogen end up as the same NH₄⁺ the grass uses — the difference is speed. Try each.