Test Tube Holders

“Test tube holders” can refer to two main types of laboratory equipment:

1. Test Tube Holder (Clamp/Tong): This is a tool, usually with a spring-action or cross-pattern grip, used to safely hold a single test tube, especially when it is hot (e.g., during heating over a Bunsen burner) or should not be touched by hand. It provides a secure grip for handling one tube at a time.
2. Test Tube Rack: This is a stand or shelf with multiple holes used to hold multiple test tubes upright simultaneously. They are essential for:
   • Organizing tubes.
   • Safety (preventing spills).
   • Safe storage and transport.

Test tube racks come in various materials (wood, metal, plastic) and designs, accommodating different sizes and numbers of tubes.

Test Tube Holder used in Laboratory

A test tube holder is a laboratory tool designed to securely hold and manipulate a single test tube, especially when it is hot or contains hazardous materials.¹

Its primary functions are:

1. Safe Heating: The most common use is to hold a test tube while it is being heated over a Bunsen burner.² It allows you to expose the contents to high heat without touching the hot glass, preventing burns.³
2. Handling Untouchable Tubes: It provides a safe way to handle a test tube that is very hot, cold, or contains volatile, corrosive, or dangerous chemicals that should not come into contact with skin.⁴
3. Manipulation: It allows for controlled tilting, stirring, and transferring of the test tube, giving the user a safer distance from the contents.⁵

Safe Use Practices:

• Placement: The holder should grip the test tube near the top, typically about 3-4 cm (approximately ⁶$1/3$ to ⁷$1/4$) from the mouth.⁸ This ensures a secure grip without interfering with the experiment.
• Heating Safety: When heating a liquid in a test tube, you must always point the open end of the tube away from yourself and others to prevent accidental spraying or ejection of contents if the liquid boils or reacts violently (called “bumping”).⁹
• Grip: Ensure the holder is clamping the test tube firmly enough to prevent it from slipping, but not so tightly that it might break the glass.¹⁰

Test tube holders are typically made of metal or wood and feature a spring-loaded mechanism or a clamp to grasp the test tube.