Ask Smithsonian: Why Are Lakes Freshwater and Oceans Saltwater?
Erosion, evaporation, and a leaky faucet, our host Eric Schulze breaks it all down (1:15)
Ask Smithsonian is a weekly video series that unravels some of science's most surprising mysteries. The series is made possible through the support of GEICO. Smithsonian members could save even MORE with a special GEICO #MemberDiscount on auto insurance.