Constructing a Solubility Curve Procedure: 1) To make a water bath, add approximately 300 ml water to a 400 ml beaker. heat the beaker, with stirring, to either 30 OC, 45 OC, 60 OC, or 75 OC, as agreed to in your pre-lab class discussion. Carefully remove the beaker, using beaker tongs, when it reaches the desired temperature.