Glass tubing to demonstrate the Bernoulli effect produced by water-flow. To demonstrate the Bernoulli effect produced by water-flow. Comprises a Bernoulli tube with central constriction, a constant-bore gradient tube, 6 lengths glass tubing, 2 swan-necked outlet tubes and 8 pre-cut lengths of connecting tubing. The 2 flow-tubes, each 500 x 13 mm length 25 mm x 150 mm spacing, extended to form 500 mm manometers with the lengths of glass tubing.