Tennis court surface type and game speed
The hypothesis that a tennis ball will bounce fastest on an asphalt tennis court surface is proven to be correct.
There are four major Grand Slam tennis tournaments each year. They are the US Open, Australian Open, French Open and Wimbledon. Only the French Open is held on a clay court surface. The US Open and the Australian Open are held on hard courts. The Wimbledon Open is held on a grass court. It takes great skill to be able to win all 4 grand slams (and players who win all 4 during their careers are said to have achieved Career Grand Slam). Few players have accomplished this in singles play, including Andre Agassi, Roger Federer, Rafael Nadal, MArtina Navratilova, Steffi Graf and Serena Williams)
This science fair project might also be repeated using a a different kind of ball (eg. basketball) instead of a tennis ball.
Try to repeat the experiment in different weather conditions like on a hot afternoon, early morning or after a rainy day as weather conditions do affect how a court surface "performs",
Tennis court - http://en.wikipedia.org/wiki/Tennis_court
Tennis court surfaces – clay, concrete and grass - http://www.essortment.com/hobbies/tenniscourtsur_sxpa.htm
Basic safety requirements