Editing Hydrogen (section)

==== Hydrogen-lifted airship ====
[[File:Hindenburg over New York 1937 (cropped).jpg|alt=Airship Hindenburg over New York|thumb|The [[Hindenburg-class airship|Hindenburg]] over [[New York City]] in 1937]]
Because {{chem2|H2}} is only 7% the density of air, it was once widely used as a [[lifting gas]] in balloons and [[airship]]s.<ref name="Almqvist03">{{cite book |last1=Almqvist |first1=Ebbe |url={{Google books|OI0fTJhydh4C|page=|keywords=|text=|plainurl=yes}} |title=History of industrial gases |date=2003 |publisher=Kluwer Academic/Plenum Publishers |isbn=978-0-306-47277-0 |location=New York, N.Y. |pages=47–56 |access-date=20 May 2015}}</ref> The first hydrogen-filled [[balloon]] was invented by [[Jacques Charles]] in 1783. Hydrogen provided the lift for the first reliable form of air-travel following the 1852 invention of the first hydrogen-lifted [[airship]] by [[Henri Giffard]]. German count [[Ferdinand von Zeppelin]] promoted the idea of rigid airships lifted by hydrogen that later were called [[Zeppelin]]s; the first of which had its maiden flight in 1900.<ref name="nbb" /> Regularly scheduled flights started in 1910 and by the outbreak of World War I in August 1914, they had carried 35,000 passengers without a serious incident. Hydrogen-lifted airships in the form of [[blimps]] were used as observation platforms and bombers during the War II, especially on the US Eastern seaboard.<ref>{{Cite web |last=Kratz |first=Jessie |date=2017-10-27 |title=Beyond the Hindenburg: Airships Throughout History |url=https://prologue.blogs.archives.gov/2017/10/27/beyond-the-hindenburg-airships-throughout-history/ |access-date=2025-04-09 |website=Pieces of History |language=en-US}}</ref>

The first non-stop transatlantic crossing was made by the British airship ''[[R34 (airship)|R34]]'' in 1919 and  regular passenger service resumed in the 1920s. Hydrogen was used in the [[LZ 129 Hindenburg|''Hindenburg'']] airship, which caught fire over [[New Jersey]] on 6 May 1937.<ref name="nbb" />  The hydrogen that filled the airship was ignited, possibly by static electricity, and burst into flames.<ref>{{Cite web |last=Follows |first=Mike |date=July 2, 2015 |title=What ignited the Hindenburg? |url=https://edu.rsc.org/feature/what-ignited-the-hindenburg/2000137.article |access-date=2025-02-19 |website=RSC Education |language=en}}</ref> Following this [[Hindenburg disaster]], commercial hydrogen airship travel [[Rigid airship#Demise|ceased]]. Hydrogen is still used, in preference to non-flammable but more expensive [[helium]], as a lifting gas for [[Weather balloon#Materials and equipment|weather balloons]].<ref>{{Cite web |last=Rappe |first=Mollie |date=May 9, 2023 |title=Researchers switch from helium to hydrogen weather balloons |url=https://phys.org/news/2023-05-helium-hydrogen-weather-balloons.html |access-date=2025-02-19 |website=phys.org |language=en}}</ref>