Conservation law, also called law of conservation, in physics, several principles that state that certain physical properties (i.e., measurable quantities) do not change in the course of time within an isolated physical system. In classical physics, laws of this type govern energy, momentum, angular momentum, mass, and electric charge.
On New Yearâs Eve, the Metrorail system will open at 7 a.m. with special extended service on all lines until 3 a.m. The additional three hours of service â consistent with past years â is a special exception to a moratorium on extended hours during the year-long SafeTrack maintenance program.
The museum is located on Independence Avenue at 6th Street SW, and admission is always free. Regular hours are 10 a.m. to 5:30 p.m., but the museum stays open until 7:30 p.m. during its extended spring and summer hours (check website for specific dates). The easiest way to reach the museum is via Metrorail or Metrobus. The closest Metro stop is Smithsonian, on the Blue and Orange lines.