How to Heat Glassware

Heating glassware is a common laboratory procedure.

Heating glassware is a commonly performed procedure in all types of laboratories. Liquids are typically heated in glassware during an experiment or scientific procedure. When glassware is treated improperly during heating, it can shatter or even explode, potentially causing injury and creating a huge mess. Safely heating glassware requires adequate preparation to prevent glass breakage as well as preparation for the inevitable glassware breakage during heating. By adequately preparing for heating glassware, you can do it safely and effectively.

Things You'll Need

• Glass flask or beaker
• Bunsen burner or hot plate
• Liquid
• Wire mesh
• Lab coat
• Hot gloves
• Goggles
• Metal test tube clamp
• Matches
• Glass test tube
• Crucible tongs

Instructions

1. Inspect the glassware for cleanliness and any physical defects such as cracks or chips. Should the glass have any defects throw it away immediately, at its liable to shatter during heating. Clean the glassware if its dirty.

2. Place the glassware on a cool hot plate or an unlit Bunsen burner after adding the liquid to be heated. If using a Bunser burner, make sure to place wire mesh between the flame and the glassware. Put on a lab coat, heat-resistant hot gloves and goggles to protect yourself in case of breakage during the procedure.

3. Turn the hot plate on or light the Bunsen burner with a match. Should you be heating a glass test tube, make sure to use a metal test tube clamp to hold it over the Bunsen burner flame. Make sure top of the glassware is not obstructed, as this could cause an explosion due to pressure buildup.

4. Lower the heat once the liquid begins to boil. Allowing the liquid to excessively boil could cause the glassware to crack.

5. Remove the glassware from the Bunsen burner or hot plate using crucible tongs once the liquid in the glassware has cooled below boiling. Removing the glassware while the liquid is hot could cause the bottom to crack and fall out.

Tips & Warnings

• Never put hot glassware in cool water or hot water in cool glassware. The rapid temperature change can and will cause the glass to fracture and break.

• Always disconnect the gas from a Bunsen burner and unplug a hot plate after use. Leaving the heat on these devices after use could cause burns or a fire.

• Always wear gloves, goggles and a lab coat when heating glassware to prevent injury in case of an accident.

• Keep a fire extinguisher and fire blanket nearby to put out a potential fire immediately.

References

• Science Tool Box: Care of Lab Glassware
• San Benito Consolidated Independent School District: Safety and Laboratory Rules
• BCIT Online Chemistry Resource: Lab Safety Rules
• University of Nebraska: Ground Glass and Glassware Safety

Resources

• Tutor Next: Common Apparatus Used in Chemistry Laboratory