Inquiry: Boiling Water in a Syringe

What is the lowest temperature at which water can be made to come to a boil within a syringe?

• Thermometer (or temperature probe)
• Beakers
• Hot plate
• 50 mL syringe with caps

Strong intermolecular forces of attraction exist between molecules of water. This is a direct result of the polar nature of water molecules.  The intermolecular attractions between molecules of water can be overcome by reducing the external pressure acting on the surface of the water. Thus, when the air space within a sealed syringe containing water is expanded, the air trapped in the cavity exerts less pressure on the liquid beneath it. Under less pressure, the liquid molecules respond by spreading out. If the water in the syringe is warmed slightly, the molecules may contain sufficient energy to overcome the intermolecular forces of attraction, and come to a boil inside the syringe when the plunger is pulled. The objective of this activity is to allow you, the student, to devise a procedure that will allow you to find the lowest temperature at which water can be made to come to a boil within a syringe. 

Students, you must devise an experiment with suitable controls that will allow you to come up with a valid answer to the question.

Water’s normal boiling point is 100 ºC. You will  be working with water that is well below its normal boiling point. DO NOT to work with water that is overly warm. You will not have to heat the water extensively in this project.