In an orchestra, the viola often has a larger role, providing the middle space between the violins and the lower strings. Violas are slightly larger than violins, the bows are heavier, and strings are ordered differently. Violists read their music from the alto clef rather than the treble clef. The top string on a violin is an ‘E’, but the top string on a viola is the ‘A’ five notes below that. The overall pitch of a viola will generally sound lower, and a bit more mellow than a violin. It’s sound is gorgeously rich and full. Many composers give the viola section really great bits of tune, which conductors often refer to as ‘viola moments’!