Google is commemorating the achievements of the scientist Julius Richard Petri today with a Google Doodle that shows his invention - the Petri dish - in action.

Today would have been the German bacteriologist's 160th birthday. In the animation on the Google homepage, the word 'Google' is replaced with a series of the dishes in the Google colours. A hand appears, swabbing each of them, then you can watch as the bacteria grow.
The dishes are ubiquitous - familiar to anyone with lab experience from school to advanced biotech: transparent plates with small walls, used for culturing cells. Invented while Petri was assistant to Robert Koch, the father of modern bacteriology, the dish allowed scientists to purify or clone bacterial colonies derived from single cells, allowing them to identify the bacteria causing diseases - a simple idea that paved the way for countless discoveries and advances.

Petri died in 1921, aged 69..