The Lascells Rotary Table is a strong turntable suitable for rotational motion demonstrations. Constructed from two 18mm plywood platforms covered in non-slip matting, with 20cm bearings in between, the turntable can support balanced loads of up to 100kg and is most effectively used to demonstrate conservation of angular momentum.
An effective demonstration is to place the platform on top of a stool and get a student to sit centrally on the platform, so that they can be rotated with their legs moving around the outside of the stool. If they are then rotated with arms held into their shoulders (with a 1-2kg mass in each hand for better effect), once the platform is up to speed, they can then extend their arms outwards. The rotational speed will decrease as they extend their arms and increase again when the arms and masses are brought back inwards. Examples of this include ice skaters spinning, competition divers on high diving boards, or playground roundabouts. In each case, angular momentum has to remain constant, so if the effective radius of the mass is reduced the angular speed has to increase to compensate. Platform dimensions 40 x 40 cm.
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