Put a 600 cm3 about 2/3 full of water on the hot plate to boil. Meanwhile dry a 250 cm3 Erlenmeyer flask gently using a
paper towel. If necessary put the flask briefly on the hot plate. Then allow the flask to cool. While it is cooling fit it with
the rubber stopper and pinch clamp assembly. Insert the stopper into the flask and then gently immerse the flask into
the boiling water as far as possible and clamp it in place with the clamp. Make sure that the rubber tubing coming out of
the stopper is open See diagram below