SCIENCE -- October 23, 2013 at 6:01 PM ET

Science lovers celebrate Mole Day with guacamole and chemistry

Creative commons photo of a mole found in France by flickr user J. Marsh

It's October 23, or Mole Day for chemistry enthusiasts. From 6:02 a.m. to 6:02 p.m. students and teachers celebrate their love of chemistry with Avogadro's number -- 6.02 x 10^23, a unit of measurement based on the number of molecules in 12 grams of carbon-12. Chemists use Avogadros number to determine how many molecules are in a volume.

Phil Plait, an astronomer and blogger for Slate, explains:

Remember, this whole thing came up because Avogadro figured that equal volumes of gases have the same number of molecules in them. Now we can hang an actual number on that! A mole of any gas has the same volume, and it turns out that at sea level and 0 degrees C (what's called standard temperature and pressure, or STP) that volume is 22.4 liters. So if you have a balloon that holds 22.4 liters, then you can know that it has a mole of molecules inside it. Doing a bit of math, I get that the balloon (assuming it's a sphere) would be about 35 cm across, or just over a foot: about the size of a party balloon. Huh. How about that!

Here's another example: We know that it takes two moles of hydrogen (so a mass of about two grams) combined with one of oxygen (a mass of about 16 grams) to make a mole of water molecules. So a mole of water has a mass of 18 grams (about two-thirds of an ounce). Since a cubic centimeter (about the size of a six-sided die) of water has a mass of one gram, it would take 18 cc of water to get a mole.

...And that is the true spirit of Mole Day. Have a good one. To celebrate, make some guacamole, and use a mole of avocados. How much is that? At 200 grams per avocado, that bowl of guac would outmass the Moon. And that's not even counting the green cheese.

You can read his blog post about Mole Day and moles here.

And an instagram feed of how others are celebrating #moleday:

Remember chemistry sets when you were a kid? The Moore Foundation is holding a competition to design a chemistry set for all ages.

For other chemistry fun today, check out ASAP Science's version of the "Elements" song -- now in order:

Or this video about the chemistry of a cheeseburger bun from the National Science Foundation's Science360:

H/T Rebecca Jacobson