Aaron Copeland was an American composer, conductor, and one of the most influential figures in American music. He is best known for his works for orchestra, including 'Appalachian Spring' and 'Fanfare for the Common Man'. Strontium is a chemical element with symbol Sr and atomic number 38. It is a soft silver-white or yellowish metallic element that is highly reactive chemically. It is found in the minerals celestine and strontianite and is used in alloys, fireworks, and ceramics.