Final answer:
Boiling chips are used to provide a surface for bubbles to form, preventing superheating and bumping when heating liquids in the laboratory, ensuring safe and even boiling.
Step-by-step explanation:
Boiling chips, also known as boiling stones, are small, porous pieces of material that provide a rough surface which allows bubbles to form during the boiling process. When a liquid is heated, it can sometimes get superheated and momentarily exist at a temperature above its normal boiling point without actually boiling. This is a hazard because when the liquid does finally boil, it can do so violently, causing a phenomenon known as bumping. Bumping can cause spills or potentially dangerous laboratory accidents.
To prevent this, boiling chips are added to the liquid before heating begins. They serve as nucleation sites that enable the formation of vapor bubbles, ensuring that the liquid boils evenly and gently. This is particularly important when heating liquids in a smooth vessel or container, such as a test tube, where the smooth surface inhibits bubble formation. Without these nucleation sites, the motion needed to trigger boiling could cause the superheated liquid to surge out of the container when it's moved. The analogous situation can occur when superheating liquids in a microwave: upon moving the cup, the liquid may abruptly boil over due to the lack of nucleation sites.