Editing Test tube (section)

=== Ignition tube ===
[[File:Ignition Tube.png|thumb|An illustration of a setup using an ignition tube. The ignition tube is being heated by the Bunsen burner on the left, with the heated gas escaping from the tube to the pan via the delivery tube on top and at right.]]

An ignition tube is used in much the same way as a boiling tube, except it is not as large and thick-walled. It is primarily used to hold small quantities of substances which are undergoing direct heating by a Bunsen burner or other heat source.<ref>{{Cite book|last=Nichols|first=William Ripley|url=https://books.google.com/books?id=jvo4AAAAMAAJ&q=ignition+tube&pg=PA7|title=An Elementary Manual of Chemistry: Abridged from Eliot and Storer's Manual, with the Co-operation of the Authors|publisher=Ivison, Blakeman, Taylor|year=1877}}</ref> This type of tube is used in the [[sodium fusion test]].

Ignition tubes are often difficult to clean due to the small bore. When used to heat substances strongly, some [[Char (chemistry)|char]] may stick to the walls as well. They are usually disposable.