Context and question: Fused quartz is a glass made from chemically-pure SiO2 (silica). It has excellent thermal shock characteristics, being able to survive immersion in water while red hot. However, its high melting-temperature (1723 °C) and viscosity make it difficult to work with. Normally, other substances are added to simplify processing. One is sodium carbonate (Na2CO3, "soda"), which lowers the glass transition temperature. The soda makes the glass water-soluble, which is usually undesirable, so lime (calcium oxide [CaO], generally obtained from limestone), some magnesium oxide (MgO) and aluminium oxide (Al2O3) are added to provide for a better chemical durability. The resulting glass contains about 70 to 74% silica by weight and is called a soda-lime glass. Soda-lime glasses account for about 90% of manufactured glass.
What causes glass to dissolve in Na2CO3?
Answer: unanswerable
Context and question: There are traditions long associated with football games. Students growl like wildcats when the opposing team controls the ball, while simulating a paw with their hands. They will also jingle keys at the beginning of each kickoff. In the past, before the tradition was discontinued, students would throw marshmallows during games. The Clock Tower at the Rebecca Crown Center glows purple, instead of its usual white, after a winning game, thereby proclaiming the happy news. The Clock Tower remains purple until a loss or until the end of the sports season. Whereas formerly the Clock Tower was lighted only for football victories, wins for men's basketball and women's lacrosse now merit commemoration as well; important victories in other sports may also prompt an empurpling.
What football game tradition has since been discontinued?
Answer: students would throw marshmallows during games
Context and question: The success of the British Commandos during World War II prompted U.S. President Franklin D. Roosevelt to authorize the creation of an intelligence service modeled after the British Secret Intelligence Service (MI6), and Special Operations Executive. This led to the creation of the Office of Strategic Services (OSS). On September 20, 1945, shortly after the end of World War II, Harry S. Truman signed an executive order dissolving the OSS, and by October 1945 its functions had been divided between the Departments of State and War. The division lasted only a few months. The first public mention of the "Central Intelligence Agency" appeared on a command-restructuring proposal presented by Jim Forrestal and Arthur Radford to the U.S. Senate Military Affairs Committee at the end of 1945. Despite opposition from the military establishment, the United States Department of State and the Federal Bureau of Investigation (FBI), Truman established the National Intelligence Authority in January 1946, which was the direct predecessor of the CIA. Its operational extension was known as the Central Intelligence Group (CIG)
Who's secret intelligence service was the US's modeled after?
Answer:
British