Ada Lovelace Day

How Ada Lovelace Day started

In 2009 Suw Charman-Anderson, a British journalist and social media consultant, was tired of hearing that there were no women to invite as speakers at technology conferences. She made a public pledge: she would write a blog post about a woman in technology she admired if 1,000 other people promised to do the same. Nearly 2,000 signed up, and the first Ada Lovelace Day was held on 24 March 2009.

The day later moved to October and settled on the second Tuesday of the month. Its organisation, Finding Ada, added live events in London featuring women scientists, engineers and comedians, along with resources for schools. In 2022 Finding Ada said it could no longer fund its flagship London event, but the day itself carries on: universities, schools, libraries, companies and science societies around the world mark it each October with talks, profiles and Wikipedia editing sessions that add articles about women in science.

The idea is simple and still the heart of it. Pick a woman in STEM, past or present, and tell people about her work. Lovelace is the namesake, not the only subject.

Ada Lovelace Day dates

Many schools and universities hold their events on a nearby day. The first Ada Lovelace Day, in 2009, was on 24 March.

Who Ada Lovelace was, in brief

Augusta Ada Byron was born in London on 10 December 1815, the only legitimate child of the poet Lord Byron and Annabella Milbanke. Her parents separated weeks later and she never knew her father, who died in Greece in 1824. Her mother, a keen amateur mathematician, had her tutored in mathematics and science, partly in the hope of steering her away from her father's temperament.

In June 1833, aged 17, she met the mathematician and inventor Charles Babbage and saw a working section of his Difference Engine, a calculating machine. They became lifelong friends. In 1835 she married William King, who became Earl of Lovelace in 1838; they had three children. She studied advanced mathematics by correspondence with Augustus De Morgan in the early 1840s. She died of cancer on 27 November 1852, aged 36, and was buried, at her own request, beside her father at Hucknall in Nottinghamshire.

The 1843 Notes and Note G

Babbage's second design, the Analytical Engine, was meant to be a general-purpose calculating machine. It had a “store” (memory) and a “mill” (processor), and it would be programmed with punched cards borrowed from the Jacquard loom used in silk weaving. It was never built.

In 1842 a young Italian engineer, Luigi Menabrea, published a French article about the engine based on Babbage's lectures in Turin. Lovelace translated it into English and, at Babbage's suggestion, added her own notes, labelled A to G. They ended up about three times as long as the article. The translation and Notes appeared in August 1843 in Taylor's Scientific Memoirs, signed only with her initials, A.A.L.

Note G, the last, sets out in a large table how the engine would calculate Bernoulli numbers, a sequence important in number theory, step by step: which values go into which storage columns, which operation runs at each stage, and how a group of operations repeats. That table is why Lovelace is often called the first computer programmer.

Historians argue about that title. Babbage had sketched earlier routines for the engine in unpublished notes from the late 1830s, and he said he helped with the Bernoulli example; some writers have argued that Lovelace's mathematical role was small. Close study of her letters and drafts, especially by Christopher Hollings, Ursula Martin and Adrian Rice (2018), shows a capable mathematician who worked hard on the example and wrote the Notes herself. A fair summary: Note G is the first published, detailed program for a general-purpose computer, and the most far-sighted ideas in the Notes are hers. The table also contains an error in one operation, which programmers today find rather reassuring.

Her ideas in her own words

What makes the Notes stand out is not only the Bernoulli table but how she saw the machine. She compared it to the Jacquard loom:

She saw that it could work on symbols of any kind, not just numbers. If the relations of musical notes could be expressed in its notation, she wrote, “the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent” (Note A). That is an early statement of general-purpose computing.

She was also clear about its limits:

That sentence is still quoted in arguments about whether machines can be creative. In her letters she described her approach as “poetical science”, joining imagination and analysis.

Ideas for Ada Lovelace Day in class

• Keep the original tradition: each student researches one woman in STEM and writes a 150-word profile with one specific achievement and a source. Our list of women scientists in history is a starting point.
• Program without a computer: in pairs, one student writes exact instructions for drawing a shape or making a sandwich, the other follows them literally. Then rewrite the instructions with a loop, as Note G does.
• Punched-card weaving: use squared paper as a “card” where filled squares mean a thread goes up. Weave a simple pattern with paper strips and see how changing the card changes the pattern.
• Read Note A and Note G: both are short enough to read in class. Ask students to find where Lovelace goes beyond arithmetic.
• Interview Lovelace: students prepare questions about Babbage, the Notes and her mathematics lessons, and can practise them by voice with an AI recreation of Ada Lovelace on Yuga, built from her Notes and letters. It is not the real Lovelace and can get things wrong, so check facts against the Notes or a biography.

Our questions to ask Ada Lovelace list goes further, and our Women's History Month guide has more figures for a STEM display.