Nanoseconds Associated with Grace Hopper

Nanoseconds Associated with Grace Hopper

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This bundle consists of about one hundred pieces of plastic-coated wire, each about 30 cm (11.8 in) long. Each piece of wire represents the distance an electrical signal travels in a nanosecond, one billionth of a second. Grace Murray Hopper (1906–1992), a mathematician who became a naval officer and computer scientist during World War II, started distributing these wire "nanoseconds" in the late 1960s in order to demonstrate how designing smaller components would produce faster computers.
The "nanoseconds" in this bundle were among those Hopper brought with her to hand out to Smithsonian docents at a March 1985 lecture at NMAH. Later, as components shrank and computer speeds increased, Hopper used grains of pepper to represent the distance electricity traveled in a picosecond, one trillionth of a second (one thousandth of a nanosecond).
Reference: Kathleen Broome Williams, Grace Hopper: Admiral of the Cyber Sea, Annapolis, MD: Naval Institute Press, 2004.
Currently not on view
Object Name
date made
Hopper, Grace Murray
Physical Description
plastic (overall material)
metal (overall material)
overall: 1 cm x 32 cm x 8 cm; 13/32 in x 12 19/32 in x 3 5/32 in
ID Number
catalog number
nonaccession number
Women's History
See more items in
Medicine and Science: Mathematics
Women Mathematicians
Computers & Business Machines
Data Source
National Museum of American History
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The pepper part was new to me, love it! Does "grain" mean a single peppercorn or ground pepper?
Definitely ground. If the signal travels 30cm in a nanosecond, in a picosecond it would travel 0.03cm, or around 1/100 of an inch. Much less than a peppercorn; even salt granules would be too large!
When I attended a computer science class in NVCC in the early 1980s, our professor invited Ms. Hopper, his friend and professor back in the days, to give us a lecture on computer basics where she presented us with her nanosecond wire. I just wish I had kept it, but her strong presence and kindness are etched in my memory to this day.
I just showed my 38 year old son the Grace Hopper nanosecond I received when I met Adm Hopper when I was a young Air Force Officer in the early 80’s. It’s my favorite piece of history.
I heard her speak near the end of her career. Sadly, I've lost my nanosecond wire. I recall she also carried around a coil of wire that was the distance the electrical signal could travel in a microsecond. I wonder what TSA would make of that coil and all the shorter wires in her carry-on bag at an airport today!
Around 2000 Ron Dewitt was on my EDS IBM POS Helpdesk in Raleigh, NC. I was 40 years old, he was perhaps 60. Ron gave me a wire he said he got from Grace Hopper, a "nanosecond." I have that wire on my person as we speak. I enclosed it in a glass tube with cork ends. I tell my computer science enthusiast friends about it. I just sent them the link to this page. Thank you for providing the information.
OMG putting these up at 1:1 size then making a webpage that says "calibrate your atom " with an image of a laser pointer. You can watch the nanoseconds!

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