they do change the design periodically. I found these interesting facts:
1907 – The New Year’s Eve Ball first descended from a flagpole at One Times Square, constructed with iron and wood materials with 100 25-watt bulbs weighing 700 pounds (318 kg) and measuring 5 feet (1.5 m) in diameter.
1920 – The Ball was replaced with an iron material Ball and weighing less than the original, only 400 pounds (181 kg).
1942 – 1943 – Due to World War II, the descending of the Ball was suspended.
1955 – The Ball gets replaced with a lighter Ball weighing 150 pounds (68 kg).
1981 – 1988 – Due to I Love New York campaign, there are red light bulbs and green stem in a design of an apple.
1989 – The traditional white bulbs again get put on the Ball.
1995 – The Ball gets computerized, aluminium coated, rhinestoned, and has strobe light system.
1999 – The aluminium Ball gets replaced.
2000 – 2006 – The Ball gets an overhaul for the new millennium celebrations with a design from Waterford Crystal and new technology. It weighs 1070 pounds (485 kg), measures six feet (1.8 m) in diameter and installed with 504 crystal triangles, illuminated externally with 168 halogen light bulbs and internally with 432 light bulbs of clear, red, blue, green and yellow colors. Each year there is a theme in the Waterford crystal concept with a particular chunk of designed crystals being called something, and in previous years there have been for example “Hope for Fellowship,” “Hope for Wisdom,” “Hope for Unity,” “Hope for Courage,” “Hope for Healing,” “Hope for Abundance” etc. There are strobe lights and mirrors to create bursts of excitement and special effects for the audience.
2007 – The ball is still a Waterford Crystal ball as in 2000-2006 (described above), but is lit by LED lights provided by Philips instead of halogen bulbs for the 2007 edition and the forseeable future. The ball was redesigned by a New York City lighting design firm called Focus Lighting.
2008 Marks the 100th Anniversary of the Ball Drop, so this year we will be seeing a new ball. The Times Square Alliance reports that it will be quite the spectacle:
The new Times Square New Year’s Eve Ball is more than twice as bright as the old one, with enhanced color capabilities and state-of-the-art LED lighting effects. Waterford Crystal crafted a beautiful new design for the crystal triangles on the Ball. Philips Lighting provided new solid state lighting technology that substantially increased the brightness, energy efficiency, and color capabilities of the Ball. And Focus Lighting developed a spectacular and unique lighting design for the new Ball on its 100th birthday.