Centre Of Gravity Apparatus. A simple and economical way to demonstrate the geometrical centre of gravity of two-dimensional objects, this apparatus comprises clear Perspex rod mounted on base, with suspension screw at the top and four clear acrylic shapes circular, triangular, square and trapezoid. Each shape has suspension holes at various points around the edges. The point of intersection of lines drawn vertically down from the suspension point of or more holes gives the centre of gravity for each shape. For non-permanent markings, lines can be drawn using dry-wipe pens or similar.
