Why is the ocean salty?
The Real Answer
The ocean is salty because Earth has spent hundreds of millions of years washing dissolved minerals out of rocks and carrying them to the sea. Rain and rivers slowly move those minerals toward the ocean, while some also enter through activity at the seafloor.
Once the minerals are there, evaporation removes water but leaves most of the dissolved salts behind, helping concentrate them over time. Sodium and chloride make up most of the salt in seawater, which averages about 3.5% dissolved salts by weight. The ocean also removes salts through sediments and reactions with the seafloor, so it is not simply getting saltier forever—the system is roughly balanced over long periods.
The ocean has spent billions of years collecting dissolved minerals from rivers, rocks, and the seafloor, and somehow we’re surprised it tastes like a chemistry experiment. You leave one glass of water on the nightstand overnight and won’t touch it. The planet leaves its water sitting there for billions of years and we swim in it.
The Dunce Dynamics Institute Examines Why People Ask This
Most people grow up knowing the ocean is salty but never actually wonder *why* — until they swallow seawater and their brain malfunctions for a second. It's one of those foundational facts that seems too obvious to question, which makes it perfect for suddenly wondering about at 2 AM.