SCIENTIFIC STUDY: Scientific gadgets, Newtons cradle balance balls newton's pendulum, Great for physical teachers, students in school, office white-collar workers, men and women all ages. NEWTONS CRADLE HIGH QUALITY : newton's cradle perpetual motion toy machine. balance ball for kids, newtons cradle sturdy wooden base, perfect decoration for desks and tables, whether at the office or at home. NEWTONS CRADLE LARGE : Demonstrate Newton's Laws with Swinging Balls, Watch as one ball on one end strikes the other sending the one on the opposite end into the air while the ones in the middle stay perfectly still. SWING INTERVAL TIME:Ball and ball will have a crisp sound issued, back and forth hit for only 15-25 seconds due to the resistance of the air and friction. We can not create a vacuum environment, so the balls will have some space when it is working, but it won't influence the effect of playing. Materials:Silver Ball:Stainless Steel,Base of the Newton Cradle:wood environmental paint,non-toxic; Applicable venues: home, office, science experimental classroom, science fair decoration; Perfect for Birthday, holiday, party, anniversary, ect.; Size:7.1*4.7*7.1inch