When I was a spotty schoolboy my favourite book was the Science Data Book. This amazing little book, which fit in my jacket pocket (we wore suits to school), went everywhere with me. Everywhere at school, I mean, I'm not that much of a nerd.

It contains some really handy stuff: the Greek alphabet, SI unit definitions, the periodic table, the fundamental constants, handy formulae like the Maclaurin series, (remember that?), and even a very nice table of isotopes (did you know that the half-life of vanadium-50 is 400 trillion years?).

Amazingly, there are some used copies of that little book on Amazon.

You might think that in these days of smartphones and WiFi everywhere there's no need for such things. But have you never sat in a meeting or lecture and just couldn't remember how many acres in a hectare (2.47), or when the Silurian was (417 Ma BP)? Usually it's too much hassle to pull out my phone, then find Wikipedia and the one piece of data I need. Especially when tapping away on a cell phone looks like you're texting someone 'So bored, please get me out of this meeting, call me in 5 mins?'.

So, I give you the first in a series of cheatsheets. This one has mostly basic stuff on it; future editions will have more geoscience-related content. Print it out and stick in your notebook, or maybe on your wall, right next to Signs & Symbols.