A pop gun (also written as popgun or pop-gun) is a toy gun that uses air pressure to fire a small tethered or untethered projectile (such as cork or foam) out of a barrel, most often via piston action though sometimes via spring pressure. Other variants do not launch the obstruction, but simply create a loud noise. This mechanism consists of a hollow cylindrical barrel which is sealed at one end with the projectile and at the other with a long-handled plunger. In this type, the plunger is rapidly forced down the barrel, building up internal air pressure until the projectile is forced out with the "pop" sound that lends the toy its name.
Various types of popguns have been described, such as popguns made of a hollowed-out alder, willow, or elder branch in Texas and in Appalachia in the early 1900s, used to fire a wad of paper. Similarly an 1864 American children's book advises using a piece of elder with an iron rod as the piston, shooting pieces of "moistened tow". A similar anecdote from Alabama in the early 20th century used an elder tube, oak piston, and fired peas or chinaberries. Similar tube-and-plunger toys, firing small stones, were used by the Plains Indians and Native Americans of the Pacific Northwest, though these may post-date European contact. Similar toys were found in other American Indian cultures.
- Hearst Magazines (July 1912). Popular Mechanics. Hearst Magazines. pp. 1–. ISSN 00324558. Retrieved 4 June 2013.
- Francis Edward Abernethy (1989). Texas Toys and Games. University of North Texas Press. pp. 56–. ISBN 978-1-57441-037-2. Retrieved 4 June 2013.
- Every Little Boy's Book: A Complete Cyclopædia of in and Outdoor Games with and Without Toys, Domestic Pets, Conjuring, Shows, Riddles, Etc. : With Two Hundred and Fifty Illustrations. Routledge, Warne, and Routledge, Farringdon Street; New York: 56, Walker Street. 1864. pp. 17–. Retrieved 4 June 2013.
- Billy D. Smith (October 2009). My Life As I Remember It: Growing Up in Alabama. AuthorHouse. pp. 53–. ISBN 978-1-4490-2399-7. Retrieved 4 June 2013.
- William W. Elmendorf; Alfred Louis Kroeber (July 1992). The structure of Twana culture. Washington State University Press. ISBN 978-0-87422-087-2. Retrieved 4 June 2013.
- Emory Dean Keoke; Kay Marie Porterfield (1 January 2009). Encyclopedia of American Indian Contributions to the World: 15,000 Years of Inventions and Innovations. Infobase Publishing. pp. 271–. ISBN 978-1-4381-0990-9. Retrieved 4 June 2013.
- Stewart Culin (1992). Games of the North American Indians: Games of Skill. U of Nebraska Press. ISBN 978-0-8032-6356-7. Retrieved 4 June 2013.
- Sharon M. Scott (2010). Toys and American Culture: An Encyclopedia. ABC-CLIO. pp. 67–. ISBN 978-0-313-35111-2. Retrieved 4 June 2013.