Friction

Friction is defined as a force that opposes the motion of an object. In the case of ballroom dancing, friction opposes the translational or rotational motion of the dancers.
   
Even dancers without a background in physics understand the importance of friction. If a floor is too rough or a dancer's shoes have too much traction the dancer cannot turn, spin, or even progress across the dance floor smoothly. Dancing with too much friction is no longer smooth, gliding or elegant; it's hard work.

Similarly, anyone who has tried walking across ice can has something to say about too little friction. If you thought walking across ice was challenging, grab a hardy partner and attempt a spin. The results may be unhealthy. Dancing requires friction the same way walking does, without friction translational motion by walking or dancing cannot be achieved. There is also the added risk that too little friction can displace the dancer's feet from underneath their center of gravity causing a loss of balance.

End result: dancers need a surface that does not have too much, or too little, friction. With too much friction dancers cannot turn or progress smoothly. With too little friction dancing motion becomes wild and dangerous. These concerns have lead dancers to find homegrown solutions for poor quality floors.

Shoes with suede leather soles are preferred for dancing. On most surfaces they offer enough traction that dancers don't loose their balance but still have smooth dancing motion.

Sawdust has been used on rough wooden floors to reduce friction. Since most modern establishments disapprove of dancers rolling barrels of sawdust through the door this isn't a particularly common practice. Instead dancers may use unscented, uncolored talcum powder. Small discreet piles of talcum powder may be found in the corners of dance floors where dancers may take the time to lightly dust their soles before dancing.

Glossary of Terms

Inertia

Balance

Frame

Bibliography