The head joint of the recorder is used as a noise, rhythm and effect instrument, and as a toy musical instrument with children. Because the recorder head works like a whistle, it can be used as such. With a bit practice, it is easy to play all kind of rhythms. Effects are made by opening and covering the lower end of the head joint with the hand while blowing. Many players blow harder like "normal" recorder playing (like with a pea whistle), to get a very shrill and loud sound. Professor Agnes Dorwarth of the Hochschule für Musik Freiburg argues this is an attractive way to get children to play with part of the instrument, which can make playing the entire instrument more inviting.