In their House of Sound Greg Foot and Fran Scott explain how woodwind instruments work and make all sorts of different sounds. They find out that lots of woodwind instruments are not even made of wood , and to prove the point Fran makes a woodwind instrument out of a carrot simply by making a few holes in it. Greg and Fran demonstrate that the pitch of a woodwind note depends on the amount of air that is vibrating inside the instrument. To prove this they conduct a fun experiment in which they make simple flutes out of drinking straws and make them play higher notes just by cutting bits off to make them shorter. Greg uses 3D animation to explain that on a clarinet and a recorder musicians use their fingers to cover up holes in the instruments to change how much air is inside. Cover up just one hole and less air can vibrate which makes a high note. Cover them all up and more air vibrates making a lower note. Finally Fran shows how anyone can make a balloon clarinet out of a piece of cardboard tube, a balloon and an elastic band!