Freezing Point of Naphthalene To determine the freezing point of a known substance, naphthalene II. Materials ringstand gas source test tube test tube clamps thermometer naphthalene Bunsen burner goggles hose stopwatch III. Procedure 1. Assemble the Bunsen burner, attaching one end of the hose to the burner and the other to a gas source. 2. Assemble the ring stand so that a ring clamp is attached to the stand holding the test tube that will be used in the experiment. 3. Fill the test tube to approximately 1/8 capacity with naphthalene crystals. 4. Place the ther