Windsurfing aside, many expert windsurfers will ride the same waves as surfers do (wind permitting). At one time referred to as "surfing's ginger haired cousin" by the sport's legendary champion, Robby Naish, windsurfing has long struggled to present a coherent image of the sport to outsiders. As a result of attempts to claim the word "windsurfer" as a trademark, participants have been encouraged to use different names to describe the sport, including "sailboarding" and "boardsailing". The term "windsurfing" has persisted as the accepted name for the sport, and the word "windsurfer" persists for both participants and equipment. Windsurfing is predominately undertaken
Thermodynamic activity liquids) is normally taken as unity (the number 1). Activity depends on temperature, pressure and composition of the mixture, among other things. For gases, the activity is the effective partial pressure, and is usually referred to as fugacity. The difference between activity and other measures of composition arises because molecules in non-ideal gases or solutions interact with each other, either to attract or to repel each other. The activity of an ion is particularly influenced by its surroundings. Activities "should" be used to define equilibrium constants but, in practice, concentrations are often used instead. The same is often true of