Exercise ball a chair because of ergonomic considerations or biomechanical reasons. This large plastic ball, known as a "birth ball", can also be used during labour to aid the descent of the fetal head into the pelvis. Sitting in an upright position will also aid fetal positioning and is more comfortable for the woman. Sitting on the ball with arms placed on a bed, table or otherwise sturdy object for support and gently rocking the hips may help the woman during contractions and aid the natural physiological process of birth. Exercise ball An exercise ball, also known as a Swiss Ball, is
Crystal ball ball that is brought into full sunlight. The image of the sun formed by a large crystal ball will burn a hand that is holding it, and can ignite dark-coloured flammable material placed near it. Ball lenses such as are used to couple fiber optics are identical to crystal balls, but in tiny form, commonly 1mm to 10mm in diameter. A crystal ball lies in the Sceptre of Scotland that is said to have been originally possessed by pagan druids. Philadelphia's University of Pennsylvania Museum of Archaeology and Anthropology (also called "Penn Museum" for short) displays the third largest crystal