Jun 08

Cupcake Trains (and Atom Packing)

by Hannah Holt »


***First off, I have two giveaways on my Facebook Page this week. I’ll be doing the drawings later today, so be sure to enter soon.***

Now, here’s how to make a train out of cupcakes:

Train cupcakes

I mixed a little extra powdered sugar into my butter cream frosting to stiffen it up. But even so, some of the frosting dripped between the cupcakes. I could have packed the cupcakes more tightly, but then I wouldn’t have had the train shape I wanted, which got me thinking…

What can cupcakes teach us about organic chemistry?

Well, quite a lot, but I was thinking about atom packing. In the above, I packed my cakes together more or less like this:

loose packing

You can see the gaps between the cupcakes are fairly large, but I get nice straight lines and a rectangular shape. I could have packed them much closer together like this:

tight packing

Here you see the gaps are smaller. I probably wouldn’t get any frosting drips between these cakes, but it has the wrong shape. This might be perfect for something like a flower or clown face.

So what does this have to do with chemistry? Well, let’s consider two items with the same chemical make up: diamond and graphite.

diamond and graphite

How can two items, both made completely of carbon, have such different properties? The secret is in the packing.

Graphite has a lot more gaps (or frosting drips) in it’s structure. Its layers are bonded together loosely, so it will flake and rub off.

Diamond, on the other hand, is made entirely of strong bonds. So while graphite is good for sketching, diamond would be better suited for etching. Different “packings” will result in materials with different uses, just like my cupcake arrangements.

This isn’t a perfect analogy because I’m comparing a two-dimensional model (cupcake packing) to a three-dimensional one (crystalline structure). But the principle is the same, and I thought this might be a fun example for young children. Older kids could do something cooler, like hot-gluing ping-pong balls together:

{Image from the Purdue University Chemistry department website.}

Science is everywhere. :)



  1. Gramma Holt

    I learn neat stuff at this website!

  2. Stacy S. Jensen

    You had me at cupcake! Great train and a fun lesson too.

  3. julie rowan zoch

    Cupcakes, pencils and diamonds – they can all be my best friends!

  4. Tina Cho

    Wish you would’ve been my science teacher, Hannah! Fun train cake! My son used to be into trains big-time!

  5. Erik - This Kid Reviews Books

    Do you give live presentations across the USA? 😉

  6. Carrie F

    I see you have trains on the brain lately. :-) My son would love your other example, too. He’s really into diamonds.

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