Research Training Program

Adam Freeburg
Pennsylvania State University
University Park, Pennsylvania

Dr. Bruce Smith, Ph.D.
Supervising Scientist
Department of Anthropology

"The Research Training Program provided an invaluable opportunity: to research and collaborate with the leading scholars of my field."

Experimental Carbonization of Helianthus annuus (sunflower)

Archaeology studies past cultures through materials that remain in the ground today. Although some objects preserve fairly well when buried for hundreds of thousands of years, most do not. Sometimes, the process that aids in preservation of a certain material causes even more problems when the material is recovered. Such is the case for sunflower seeds. Usually, vegetable matter rots before it can enter the archaeological record. However, carbonization of a seed will expel moisture and aid in the preservation of the seed. Unfortunately, this process also causes the seeds to shrink. So, when the seeds are dug up a thousand years later, they are smaller than they originally were. Archaeologists use the size of a seed to determine whether it is from a wild or domesticated plant. But, the original size must be approximated from the shrunken seed. For the past thirty years, these approximations were calculated using a single, static set of correction values. Through experimentation, these values have been confirmed as inappropriate to apply to all sunflower seeds preserved through carbonization. Wild and domestic sunflower seeds were acquired through the USDA. Seeds were measured, carbonized in a controlled environment of differing temperatures and times, then measured again. It was found that sunflower seeds do not shrink according to the predictions of the previous study. Instead, the amount of change in a seed depends on many factors, including moisture in the seed, amount of heat applied, and for how long they were exposed to heat. Further research will hopefully provide reconstructive models that more accurately account for variability in seeds and the carbonization process. Plant domestication research such as this adds to the knowledge of past societies and how they changed through time. Additionally, knowing the process of domestication assists modern farmers, keeping economically important strains of plants healthy and productive.

This research was supported by a grant from the Smithsonian Women's Committee.

Letter of Gratitude