Bill shows how units of length, such as a meter, can be used to measure the mass of an object. He mentions a few unit conversions, most notably that a liter of water is equivalent to a kilogram and stresses that only three-tenths of a meter and water are needed to measure an object's mass.
Two officers seek to interrogate Cesar Chavez about his possible affiliation to the Communist party. When they suggest performing a search of the property, Chavez stops them by asking for a warrant. He mentions the Bill of Rights multiple times in his conversation with the officers to remind them that his group's actions are protected by the Constitution.
Penny asks Sheldon for advice on whether or not she should date Leonard, and during the conversation, Sheldon corrects her use of physics terms. He then explains the Schrödinger's Cat thought experiment to help her think about the situation.