About 1980, the United States Postal Service detached the two-thirds of greater Oxon Hill that was furthest from Washington, D.C. and re-defined that part as a new postal designation, Fort Washington, MD.
A gallon of paint is heavier than a gallon of water. Mostly anything that mixes a solid into the water will be heavier than water. Most homes have a can of Spackle , which is a common liquid for patching drywall and it is almost twice as heavy as water. Of course,mercury is the heaviest liquid, but isn't common around the house anymore. But if you have a mercury switch for turning on your furnace, then that would be the heaviest common liquid by far. Which, I assume, discounts mercury - oil is lighter than water, so two choices would be sugar water or salt water.
Symbol H A colorless, odorless, highly flammable gaseous element that is the lightest and most abundant element in the universe. It occurs in water in combination with oxygen, in most organic compounds, and in small amounts in the atmosphere as a gaseous mixture of its three isotopes (protium, deuterium, and tritium).