First, Let us first define what a flute is. A flute is an aerophone (an instrument that uses air to produce its fundamental tone) that is hollow throughout its length and has bored tone holes that when covered change the tone’s pitch. Generally, the more holes that are covered produce a lower pitch. There are hundreds of flutes from all over the world so it is impossible to cover them all, but the following are the most common to my knowledge.
Modern Boehm System flute: Germany
Theobald Boehm, a German inventor and musician, set to redesign the Irish flute to give it more volume. These “Boehm” flutes had bigger tone holes, but eventually became too large for common fingers. This obstacle drove him to design round, spectacle-looking keys attached to a system of rods and levers. He also changed the flute’s construction, both by making it truly cylindrical (the Irish flutes were conical in construction, narrower towards the foot), and making it of silver instead of wood. The Boehm System flutes are the standard used in today’s school bands and professional symphonies.
A recorder is a very inexpensive, entry-level flute. Usually made of plastic, recorders are played vertically and have tone holes that are covered by the player’s fingers. It has a mouthpiece with a reed that is activated when air passes through. The left hand covers the holes closest to the mouthpiece – three holes in the anterior, exposed portion for the index, middle and ring fingers, and one in the posterior portion for the thumb. The right hand covers the holes closest to the foot of the instrument, all in the anterior portion of the recorder from the index to the pinky. Most recorders are diatonic instruments in the key of C, but are capable of playing chromatically (half steps) by the use of alternate fingerings.
Irish flute (Albert system?): Ireland
The Irish flute was the standard instrument in the Baroque and Classical symphonies of Back, Haydn, Vivaldi, Mozart, and Beethoven. It is modeled after the recorder (Key of C, holes bored into the cylindrical body), with some modifications. It is played horizontally and has a hole that air passes through at the head joint. It also has a few (up to six) keys that are manipulated by the pinkies and sides of the flutist’s fingers.
Ocarina: Central America
Usually made of clay, the ocarina is a hollow bulb-like wind instrument with several holes bored into it. The holes when covered and opened in different combinations produce different pitches. Most ocarinas have a whistle-like mouthpiece to breathe into that protrudes from the bulb-like body.
Penny Whistle: Ireland
Much like the recorder, the Penny Whistle is a cylindrical tube with holes bored into it that change the pitch when covered. It also has a small mouthpiece with a reed that is activated when air passes through. It is made usually of stainless steel and it has a very high, shrill tone.
Zampoña (Andean pan flute): Andes region
A very mellow toned instrument, the Zampoña is a series of bored out wooden tubes of different lengths, tied together in sequence. The player changes the pitch by blowing into the different tubes.
Kena (Quena): Andes region
The kena, or quena, is another recorder-type flute. This rustic instrument is a hollow, cylindrical tube made of wood and it is played vertically. The difference between the Kena and the recorder or penny whistle mentioned above, is the player blows an intense air stream into a crescent-shaped notched carved into the top of the instrument’s cylinder.