University of Pennsylvania Museum of Archaeology and Anthropology

For the good of the exhibit

October 13, 2010

Exhibits team members Kevin and Ed trying to create some freeze dried grapes.

Down in the exhibits department, we’ve been busily working on the upcoming Secrets of the Silk Road exhibit. There is a lot to create, coordinate, and figure out with an exhibit this size. One thing we really wanted to focus on for this exhibit was adding experiences where the visitors can interact with the exhibit. There are lots of different learning styles out there, and allowing for visitor interactivity can really help drive the information home. Plus, it’s fun for families and other groups to experience things together. I’ve been working with another exhibit department employee, Kevin to comes up with ideas and tests them out.
One section of the exhibit will go into different levels of detail on decomposition and mummification. We brainstormed lots and lots of ideas for how to illustrate some of these concepts in fun and interesting ways. I won’t reveal all of our tricks here, you’ll have to check out the exhibit for that, but, one way we are talking about natural mummification is through raisins.

A raisin is a mummy you eat!

Yes, raisins. You may ask yourself, “How do raisins help talk about natural mummification?” To that I give you one of our favorite sayings in exhibits, “Raisins are mummies you eat!”  (and they’re not the only ones either…)
The mummies in the Silk Road exhibit mummified naturally. The climate in the Tarim Basin (located in Western China where the mummies were found) was extremely dry, and the soil was very salty. The dry air caused the bodies to dry out, or desiccate, before they could decompose. The salt helped this process as well. Raisins are dried out grapes, so they are a nice, simple analogy to the mummies on display.
So we decided we wanted to put some grapes on display in different stages of drying, all the way to the raisin that we know and love. Sounds simple, right? Not quite. For the safety of the objects, we can’t put anything in the gallery that might spoil or worse, attract bugs. Fake half-dried grapes aren’t the sort of thing you can pick up at your local craft store. We asked ourselves, “Is there a way to kill all of the bacteria within the grape, then seal it resin, so that we have gallery-ready models?”

Hey, what's in that sony box? Turns out, it's liquid nitrogen!

“What about freeze drying?” we thought. Kevin made some contacts with the Chemistry department here at Penn, and we got our gloved hands on some liquid nitrogen. We wanted to test if freezing the grapes/ raisins in liquid nitrogen, then promptly resin-coating them, would work. And before all of you point out the many flaws with this plan, let me say, “We know there are many flaws with this plan.” But, since we already had the resin, the grapes, and the liquid nitrogen, we figured it’s worth a shot.
What does an exhibits staff do with a container of liquid nitrogen?
Freeze as much stuff as we can. Apples, flowers, Swedish fish, foam, and of course, lots of grapes and raisins. It seems that the temperature made the resin resistant to hardening, but it offered a great break in the work day, and we know for next time.
More to come.


A frozen swedish fish (it was shattered moments later)

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