Test tube

A test tube, also test tube (French: éprouver = check ) or test tube called, is a small, open on one side, glass container.

Test tubes are used in laboratories for chemical reactions, investigations, for the storage of small quantities of liquid and much further. They are manufactured in various sizes (approximately 2 to 20 cm in length, diameter from 0.6 to 3 cm). A standard size in chemical laboratories is 16 cm long with a diameter of 16 mm. If necessary, they can ( colloquially also called plugs ) are sealed with plastic films, aluminum caps, cork, rubber or plastic plugs.

In trade there are also tubes with standard ground joints, which can be closed with a ground glass stopper, glass or plastic. Some are printed with a volume scale in milliliters.

Glasses that are to be heated in a flame (for example over a Bunsen burner ) are generally thin-walled, in order to avoid breakage due to thermal stresses. However, there are also thicker walls made ​​of fireproof glass.

The price of a simple test tube in standard size ( 16 cm ) is about 10 cents or upwards, wherein the material used and the variation play a crucial role. For example, a cost of brown glass with ground joint and Olive between 3 and well over 10 €.

Test tubes are available in various shapes, such as round, conical or flat bottom, with flare or straight edge.

For handling the test tube is often held with a test tube holder. The usual design is similar in shape to a longer clothespin of wood with a metal spring; other Regenzglasghalter are bent from wire, consist of two in a wooden handle enclosed flat spring steel tabs or a metal bracket with a wooden handle.

Experienced chemists clamp a test tube with the middle finger on the palm of your hand, open with your thumb and forefinger the rotation lock or a ground-glass stopper reagent bottle and hold it fixed so that ( a drop could contaminate it) and fill the liquid in the test tube a. With this method, powdered non-clumping reagents can be introduced, which can then be metered by tapping with the index finger of the hand holding the bottle, the amount.

When heating Regenzgläsern the heating is interrupted regularly and successively shaken by briefly tapping the test tube in the middle section with ring finger, middle finger and index finger of the content, without leading to spillage of liquid or burning on the hot glass. The opening of the test tube is not directed to the face to prevent scalding or burns due to bumping.

Often test tubes (also known as test tube rack test tube rack or ) in a test tube box provided.