Test Tube: Uses and How to Use It
Test Tube: Uses and How to Use It
A test tube is a small glass tube with a rounded bottom and open mouth, used to react, heat and observe small amounts of substances. Test tubes stand in a rack and are held with test-tube holders when heated.
What is a test tube used for?
- Reacting small amounts of chemicals for qualitative tests such as Benedict's test.
- Heating small amounts of liquid or solid over a burner.
- Growing microbes on agar slants or in broth.
- Holding samples temporarily for observation.
Parts of a test tube
- 1Mouth (sometimes rimmed) – a rim eases pouring and holding
- 2Body – heat-resistant borosilicate or soda glass
- 3Rounded bottom – heats evenly and is easy to clean
How to use a test tube
Do not overfill
Fill no more than one-third if it will be heated or shaken, so the contents do not spurt out.
Heat at an angle with a holder, mouth away from people
Hold the tube near its mouth with a test-tube holder, tilt it about 45° and heat the upper part of the liquid while shaking gently (1). Point the mouth away from yourself and others.
Mix by flicking the bottom
Hold the tube near the top and flick the bottom with a finger, or use a vortex mixer. Do not cover the mouth with your finger and shake.
Keep it upright in a rack
Always stand test tubes in a rack rather than laying them on the bench.
Common mistakes
- Heating only the bottom at one spot: the liquid can boil suddenly and spurt (bumping).
- Pointing a heated tube at your face or at others.
Care and safety
- Clean with a test-tube brush, rinse with distilled water and dry upside down on a rack.
- Discard tubes that are cracked or chipped at the rim.
Types and sizes
Sizes are given as diameter × length, e.g. 12 × 75 mm, 16 × 150 mm and 18 × 180 mm. They come plain or with screw caps, in borosilicate glass for heating or disposable plastic for biological samples. Centrifuge tubes differ in having a conical bottom.
Test Tube at AMI Scientific
Examples of test tube available in our store. Prices exclude VAT.
Tabung Reaksi Kaca Bertepi Iwaki PA TEST10-75NPFrom Rp8.800
Tabung Reaksi Kaca Tanpa Tepi Iwaki PA 9820TST10-75NPFrom Rp10.000
Tabung Reaksi Berulir Tanpa Tutup Iwaki PA TST-SCR13From Rp15.000
Tabung Reaksi Bertepi Berskala Iwaki PA 9802TST15From Rp25.000
AMI Scientific supplies laboratory glassware, instruments and chemicals with tax invoices and delivery across Indonesia.
Frequently asked questions
Why is a test tube heated at an angle?
Tilting increases the liquid surface area and reduces the risk of it spurting out when it boils.
How full should a test tube be?
For heating or shaking, fill no more than one-third of the tube.
Related equipment
Compiled by the AMI Scientific team from standard laboratory practice. Illustrations: AMI Scientific. Updated: 06-11-2026.
Need a test tube for your laboratory?
AMI Scientific supplies laboratory glassware, instruments and chemicals with tax invoices and delivery across Indonesia.
Available at AMI Scientific
Tabung Reaksi Kaca Bertepi Iwaki PA TEST10-75NP
From Rp8.800