8 February 23

I'm wearing my periodic table tie to celebrate both yesterday's status as Periodic Table Day and today's birthday anniversary for Dmitri Mendeleev (1834-1907). Periodic Table Day recognizes the work of English chemist John Newlands, who published the earliest known table of the elements on 7 February 1863. Six years later, Mendeleev produced a slightly different format that expanded the table into the one we recognize today. In the photo I'm holding our household periodic table display, which is a transparent block holding real samples of many of the elements!