As I write this, the clock reads helium:carbon. That’s 2:30 in normal, non-science nerd speak. What am I talking about? The chemistry clock. Instead of using numbers, this clock shows the periodic table entry for each element with the atomic weight that corresponds to its place on the clock. You’re even more confused now, aren’t you? Alright, let me put it this way – helium has an atomic mass of 2, while carbon’s mass is 6. When the big hand is pointed at carbon, and the little hand is pointed at helium, it’s 2:30. See? It’s simple!