Normally a plaque is unveiled to herald the launch of a new project, but after touring the attraction dedicated to the history of communication and information the Queen touched a tablet screen to send her message to the world.
The £15.6 million gallery features more than 800 objects and explores how breakthroughs have transformed the way people communicate over the past 200 years.
The royal tweet read: “It is a pleasure to open the Information Age exhibition today at the @ScienceMuseum and I hope people will enjoy visiting. Elizabeth R.”
The Queen’s message was sent via the official @BritishMonarchyTwitter account and is likely to be re-tweeted thousands of times by many of its 722,000 followers.
During her reign the Queen has encountered a rapidly-changing world of technology from the advent of the colour television to the mobile phone and the internet.
Television cameras were allowed inside Westminster Abbey in 1953 to film her Coronation and more than half a million extra television sets were sold in the weeks running up to the historic event.
Five years later she made the first trunk call in the United Kingdom and when email technology was in its infancy, the Queen became the first monarch to send one of the electronic messages, in 1976 during a visit to an Army base.
The concept of video-sharing website YouTube was explained to her by Princesses Beatrice and Eugenie before she launched her own channel on the site in 2007 to promote the British monarchy.
Her own website, www.royal.gov.uk, was launched in 1997 during a visit to Kingsbury High School in Brent, north west London.
Other technological milestones for the Queen include personally uploading a video on to YouTube, during a visit to the Google offices in London in 2008.
The Duke of York is the most prolific tweeter in the royal family and has an account under his own names and signs off messages he has written with AY, for Andrew York.
The micro-blogging site has been used by her grandson Prince Harry, who sent his first official tweet in May, but he admitted during the summer he no longer has a personal account, when chatting to a group of students who were promoting his Invictus Games on social media.
The Queen and members of her family are represented on Twitter by the account @BritishMonarchy, while @ClarenceHouse covers the Prince of Wales, Duchess of Cornwall, Duke and Duchess of Cambridge and Prince Harry.