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 arbitrary; however, it is often chosen out of mathematical or experimental convenience. Alternatively, it is also possible to define an "absolute activity", , which is written as: The activity coefficient , which is also a dimensionless quantity, relates the activity to a measured amount fraction (or in the gas phase), molality , mass fraction , amount concentration or mass concentration : The division by the standard molality or the standard amount concentration is necessary to ensure that both the activity and the activity coefficient are dimensionless, as is conventional. The activity is the same regardless of the ways to express