This family of instruments can play louder than any other in an orchestra or band and can be heard from very far away. Brass instruments are essentially long pipes that widen at the end to make a bell-like shape.
The string family is the largest and most well known in a symphony orchestra.
The percussion family is the largest in the orchestra. Unlike most of the other players in the orchestra, a percussionist will usually play many different instruments in one piece of music.
This family of instruments produce sound by blowing into a tube, and are called woodwind because originally they were all made from wood. Today, they are made of wood, metal, plastic or some combination of both.
Music theory is essentially what you would call the language of music. While many may find music to be an instinctive thing, music theory gives you a way to express the music you hear and play in a concrete manner.