Difference between violin, viola, cello and double bass

The Violin is the highest pitched string instrument and is held on the left shoulder, pointing to the left.

The Viola is held the same way and its lowest pitch (C) is only 5 tone steps lower than the lowest pitch of the violin (G).

The Cello has the same tuning as the viola, just one whole octave (8 notes) lower. The cellist sits on a chair, with the cello body between the knees.

The Double Bass is the largest non-fretted string instrument and its lowest pitch is 5 notes lower than the lowest cello pitch.