Google is celebrating its 25th birthday with a special Doodle. Anyone who currently visits the Google homepage is greeted by a changing Google logo, starting with the first iteration and then transforming through the various versions released throughout the years, up to the current logo of the search engine. At the end, the iconic double "O" changes to a 25, and if you click on the doodle, a shower of confetti explodes. As the company writes in its blog, Google is not only celebrating its 25th birthday today, but also 25 years of "curiosity" from users, which it says brought the company to the point where it stands today. "For our birthday, we're celebrating in ways you might have come to expect over the last quarter-century. Our homepage doodle today honors the evolution of the Google logo, and if you search for (or hum) birthday-related queries, you might see a little surprise."

Google is offering US schoolchildren the chance to design their own Doodle to appear on its homepage. The Google Doodle sees the Silicon Valley search giant periodically replace its familiar logo with a sketch, often animated, to celebrate a public figure on an anniversary associated with them or their achievements. Doing so offers an opportunity to champion figures from the arts and sciences who have distinguished themselves through innovation or by blazing a trail for others and deserve to be better known. This year's theme is "hope", with entrants asked to submit a design based on their personal wishes for the future. Kids who would like to get involved have until 8pm Pacific Time on 19 March 2019 to upload a .jpg

Search giant Google is celebrating its own 20th birthday today with a trademark Doodle. Replacing its logo with an occasional animation paying tribute to eminent figures from the worlds of science, the arts and history on their anniversaries is just one of the ways in which the site's programmers can express themselves. Their quirky sense of humour is actually embedded within the software's DNA. If you tell Google to "do a barrel roll", the whole page will spin clockwise at 90 degrees before juddering to a stop. If you search for "the answer to life the universe and everything", you'll be presented with Google's calculator displaying the number 42, an in-joke alluding to Douglas Adams' cult science fiction series The Hitchhiker's Guide to the Galaxy (1978).

Google's Doodle is celebrating the Antikythera mechanism, which might just be the first computer. The mechanism was found in 1902 – exactly 115 years ago – and the discovery changed the way we saw the ancient Greeks. The man who found it, Valerios Stais, initially thought that the bronze mechanism he could see was a gear or a wheel – but on closer inspection, the metal turned out to be part of the Antikythera mechanism, an ancient and mysterious analogue astronomical computer. The machine could be used to track and predict where the planets were, understand lunar and solar eclipses, and count towards the next Olympic Games. But its uses were various – it might also have been used for unknown forms of mapping and navigation.

Google's Now on Tap service is about to get even more useful with a new update that brings almost instant translation to mobile users. Google Now on Tap was one of the biggest features on Android Marshmallow when it was launched last year. By holding down their phone's home button, users can quickly access more information on what they're looking at without having to leave the app they're in. Since its initial launch, Google has been adding more functions to Google Now on Tap and the latest update brings three new features that make it even more useful as a service. Google celebrates William Morris' 182 birthday with a doodle showcasing his most famous designs Google celebrates Valentine's Day with a romantic Doodle Google celebrate Dmitri Mendeleev's 182nd birthday Google Doodle celebrates 90 years since the first demonstration of television or "the televisor" to the public Google marks St Andrew's Day 2015 with doodle featuring Scotland's flag and Loch Ness monster Google marks the 41st anniversary of the discovery of'Lucy', the name given to a collection of fossilised bones that once made up the skeleton of a hominid from the Australopithecus afarensis species, who lived in Ethiopia 3.2 million years ago The Google Doodle on 2nd November to mark George Boole's contribution to science Google celebrates Halloween 2015 using an interactive doodle game "Global Candy Cup" The most significant new feature is one that allows you to quickly and easily translate any on-screen text.

In its time the Google Doodle has celebrated mathematicians such as John Venn, George Boole and Hertha Marks Ayrton - as well codebreaker Alan Turing, the 100th anniversary of whose birth was 23 June 2012. Now it is the turn of Claude Shannon, who worked with Turing on Allied codebreaking during the Second World War - not at Bletchley Park, but in Washington, where Turing had been seconded in 1943 to bring the US up to speed with British cryptanalytic developments. Shannon was four years younger, 26 to Turing's 30. Although Shannon's war-time work was crucial to the Allied effort, he did devote some of his energies to more frivolous projects. In the 1070s, Shannon built the world's first juggling robot, using an Erector Set (the equivalent of a Mecanno set).