We have completed maintenance on DiscoverMagazine.com and action may be required on your account. Learn More

Stupid Science Word of the Month: Barn

A physics joke that bombed. Atomically.

By Jessica Marshall
Jan 29, 2008 6:00 AMNov 12, 2019 4:47 AM


Sign up for our email newsletter for the latest science news

barn ['bärn n. (1942)] Unit of area equal to 10^–28 m2, used to express cross sections in nuclear reactions.

To physicists Marshall Halloway and Charles Baker, uranium nuclei were “as big as a barn.” That’s why they decided—over dinner one evening—to use the term as a unit of measurement. These atomic bomb researchers set the barn equal to the cross section of a typical atomic nucleus, more or less, and during World War II its meaning was classified information. After the government declassified the term in 1948, barns spread throughout nuclear and particle physics.

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.