Flute and piccolo
Flutes are high-pitched instruments made, these days, of metal. The sound is made by blowing across the mouthpiece, similar to the way that blowing across the top of an empty bottle produces a sound. The piccolo is smaller and is a higher-pitched version of the flute.
(Number played in a concert: usually 2-3 flutes and, sometimes, a piccolo.)
The oboe makes a penetrating, haunting and evocative sound. Oboes have quite a large range, spanning three octaves. Oboists produce a sound by blowing air between two reeds which is why oboes are known as double-reed instruments. The oboe is the instrument which provides the note (an A) to which the rest of the orchestra tunes before a concert.
(Number played in a concert: usually 2-3.)
The cor anglais (English horn) is similar to the oboe but has a lower pitch.
(Number played in a concert: usually 1.)
Clarinet players sit in the middle of the orchestra, behind the flutes and next to the bassoons. Clarinets are single reed instruments and are usually made from wood. They are also popular in jazz bands.
(Number played in a concert: usually 2-3 with, sometimes, a bass clarinet and an E flat clarinet.)
The bassoon has a soft and mellow tone and is a member of the oboe family. Apart from the contra bassoon, it is the deepest-pitched of the woodwind instruments, having a range which is typically two octaves lower than the oboe.
(Number played in a concert: usually 1-2 with, sometimes, a contra bassoon.)