ABSTRACT

The Materials Research Society's Pumpkin Team recently worked together to determine the composition of the object atop McGraw Tower. Using a weather balloon, a "mace" was controllably swung into the pumpkin to collect a sample. Environmental Scanning Electron Microscopy was used to image a microscopic portion of that sample, showing it to have many characteristics in common with a similarly decayed pumpkin retrieved from a mulch pile. Based upon these observations, we have concluded that the object contains pumpkin-matter, and is most probably a pumpkin.

INTRODUCTION

While Cornellians may never know how the orange object ascended to the top of McGraw Tower, we worked to determine if, in fact, it is a pumpkin at all. Many people from across the University are convinced it cannot be a real pumpkin. A faculty member from the Department of Fruit and Vegetable science said he would be very surprised if it was. In an attempt to cut through the mystery, we devised a method to retrieve a small sample of the pumpkin.

While non-contact methods of identifying the object as a pumpkin were identified, such as infrared spectrometry, none could as conclusively identify the object as precision analysis on the ground. Thus, it was decided that a weather balloon would carry an object up to the pumpkin to obtain a sample.

Designing the specimen collection device was a challenge in itself. We wanted to obtain a sample of the outer and inner layers of the pumpkin. We decided that the simplest way to do this was to swing the collection device into the pumpkin using a separate tether. It was further decided that the device should have the ability to collect large samples (if the pumpkin was soft enough to allow a large intrusion) as well as small samples (in the event the outside of the pumpkin resisted a blunt force.) The solution was found in the use of sharpened, hollow tubes for large specimens and twelve-gauge needles for small specimens. For lack of a better description, we are calling this specimen collection device a "mace."

By using these technologies together, and coordinating their control as a team, the mace successfully swung into the pumpkin four times at roughly 8:55 a.m. March 6th, 1998. (See pictures in appendix.) The sample was retrieved as the weather balloon was lowered to the ground. While only a microscopic sample was collected (from within one of the hypodermic needle tips), it was viewed Friday evening in the Materials Science Center's Environmental Scanning Electron Microscope (ESEM.) Using this tool, Chris Regan (MS&E, '99) obtained an image of the sample. Based upon comparison of this image with one obtained from a real rotting pumpkin, we must conclude that the object atop McGraw Tower is, indeed, a pumpkin.

EQUIPMENT

The balloon was a standard latex weather balloon purchased from Kaywood Industries, inflated with 99% pure Helium gas. It's movement was controlled by the use of three nylon-twine (170 lb. test strength) tethers. A team of students was assigned to each tether, one to control the direction and length of the tether, and another to back that person and provide a communications link via two-way radios. By forming a triangle with one team behind Uris Library, one between Olin Hall and Sage Chapel, and the last in Ho Plaza, it was possible to accurately triangulate a position over the clock tower. Jeff Valentine (MS&E, '98) coordinated the teams to maneuver the balloon over the clock tower, using a digital-zoom camera and telescope (on loan from the Astronomy department, see pictures in appendix) to aide in the process. A picture of the balloon is shown in Figure 1.

Figure 1: The balloon and some members of our team

The mace, shown in figure 2, was constructed primarily by Emily Winston (ME, '00.) Using the machine shop in Rhodes Hall, she formed each of the large sample collection tubes and sharpened their edges. In addition, she introduced barbs (see figure #) that would catch any specimen and hold it in the tube as the weather balloon was lowered to the ground. The main body of the mace consisted of a platform of five welded pipes (each perpendicular to one another.) The mace was attached approximately 15 feet below the balloon by a double-redundancy nylon string arrangement to ensure a maximum level of safety and was guided (via a fourth tether) into the pumpkin.

Figure 2: The mace, held upside-down by Ed Hutchins (MSE, '99)

Environmental Scanning Electron Microscopy was performed at the Materials Sciences Center's Microscopy Lab. Microscopy was performed at 3 torr of water pressure. The image obtained from the sample is shown at 700x magnification in the Appendix.

CONCLUSIONS

ESEM results of the 0.10 mm by 0.08 mm sample obtained from the top of McGraw Tower show dimples, some external cracking and a layered structure. When a sample from a known pumpkin was placed in the ESEM (see Appendix), it was seen to have a similarly dimpled surface. The cracking on the Tower sample is expected due to the many freezing cycles the object must have went through since October. In addition, the layers are consistent with the many layers of skin a pumpkin has. Furthermore, the fracture surface seen surrounding the image is characteristic of a soft, organic material. Any metal, ceramic, or high glass transition temperature plastic would have shown a sharp break at the edges, and not the "squashed" appearance of the sample we collected. Based upon these observations, we must conclude that the object is a pumpkin or similar biological material.

THE MRS PUMPKIN TEAM

Sarah Calve '00, Dept. of Materials Sciences and Engineering

0300 Sheldon Court, Ithaca NY 14850

Nap (Nathan) Chau '00, Dept. of Materials Sciences and Engineering

122 Westbourne Lane, Apt. 1223, Ithaca, NY 14850

Emily Winston '00, Dept. of Mechanical and Aerospace Engineering

0300 Sheldon Court, Ithaca NY 14850

Brice Wu '00, Dept. of Materials Sciences and Engineering

318 Highland Road, Ithaca, NY 14850

Rob Burak '99, Dept. of Materials Sciences and Engineering

202 Eddy Street, Ithaca NY 14850

Susan Clyburn '99, Dept. of Materials Sciences and Engineering

318 Elmwood Road Apt. #3, Ithaca NY 14850

Jason Demby'99, Dept. of Materials Sciences and Engineering

140 Thurston Avenue, Ithaca, NY 14850

Ed Hutchins '99, Dept. of Materials Sciences and Engineering

115 Dearborn Place, Ithaca NY 14850

Wenbi Lai '99, Dept. of Materials Sciences and Engineering

202 Eddy Street, Ithaca NY 14850

Diana Landwehr '99, Dept. of Materials Sciences and Engineering

318 Elmwood Road Apt. #3, Ithaca NY 14850

Chen-Lin Lee '99, Dept. of Materials Sciences and Engineering

Mennen Hall, Ithaca, NY 14850

Maggie Mellon '99, Dept. of Materials Sciences and Engineering

411 Dryden Road, Ithaca NY 14850

Frank Mischler '99, Dept. of Materials Sciences and Engineering

6120 Cascadilla Hall, Ithaca NY 14853

Chris Regan '99, Dept. of Materials Sciences and Engineering

628 Steward Avenue, Ithaca NY 14850

Alex Simmons '99, Dept. of Materials Sciences and Engineering

210 Lake Street Apt. 14D, Ithaca NY 14850

Dave Haro '98, Dept. of Materials Sciences and Engineering

934 Stewart Avenue, Apt. #14 Ithaca NY 14850

Su Kim '98, Dept. of Materials Sciences and Engineering

111 Dryden road, Apt. 8H Ithaca, NY 14850

Felix Lau '98, Dept. of Materials Sciences and Engineering

211 Linden Avenue, Apt. #12 Ithaca, NY 14850

Andrew Lu '98, Dept. of Materials Sciences and Engineering

120 Oak Street, Apt. #1 Ithaca NY 14850

Jeff Valentine'98, Dept. of Materials Sciences and Engineering

522 Stewar Ave, Apt #1, Ithaca NY 14850

Jeff Yap '98. Dept. of Materials Sciences and Engineering

317 Eddy St. Apt. #1, Ithaca, NY 14850

FURTHER SUPPORT

In addition to our volunteers, many other people generously lent their time and support:

Jim Bucko, Maintenance Management

David Brand, Senior Science Editor, CU News Service

The construction crew at the Tower

CU Police Department

Keith Haselman, Safety Engineer

Cris McConkey, Technician, MS&E

Wolfgang Sachse, Professor

Mary Sansalone, Professor

Michael Thompson, Professor

Finally, we never would have been able to do it without the equipment and financial assistance of many:

The Department of Materials Science and Engineering

The College of Engineering

The Materials Science Center

The Department of Astronomy

APPENDIX