Pottery Reconstruction Puzzle

Pottery_CaddoanMounds998_8_07.jpgObjectives

Students will reconstruct a pot and learn to:

  1. Match pieces according to their provenience (location within the archeological grid) and characteristics of the pieces.
  2. Describe the vessel's attributes once it is reconstructed.

Estimated Activity Time

This activity requires approximately 45 min. of preparation. One or two hours per exercise may be required to complete the activity.

Materials

Ceramic pot -- two different hand made pots recommended, but not necessary
Shoe box full of rice
White glue
Fine tipped marker
Paper

Background

Archeologists can learn a lot of information from pottery fragments found in an archeological site. Attributes of the vessels (such as size, shape, material, and decoration) can tell much of the vessel’s construction and function.

By looking at fragments of the vessel, archeologists hope to find answers to the questions: What is it made of? How was it made? How was it fired?

Pottery is made of clay with other things such as crushed shell, bone, sand or even grass mixed in (called temper). Temper gives the clay additional workability during the construction and strength during firing. Generally, finer temper results in stronger vessels.

Several different construction methods are used to make pottery vessels. Archeologists can identify how a vessel was made by looking at the cross-sections of the broken pieces. The coiling method uses rolled lengths of clay to build up the vessel walls. These coils can be seen in a cross-section examination of the sherds. Vessels thrown on a wheel have striations and ridges not found on coiled pots.

Archeologists can also determine how a vessel was fired by looking at the hardness of the clay. Vitrified (glassy) surfaces suggest a high temperature firing, while dull surfaces are the result of lower temperature firing.

With the vessel reconstructed, the archeologist can begin to determine other attributes of the vessel such as it’s size, shape, function or decoration. These attributes can be used to answer questions about the vessel’s purpose, age, or its significance.

Preparation

Prepare an excavation "grid" by drawing twelve squares (approximately 8 inches in size) in two parallel rows. Each square is then given an alphabetic unit designation (A-K) leaving one square unprovenienced.

A       C      E      G      I      K      
B D F H J

Prepare the ceramic pot(s) by:

Wrap the vessel in a cloth and strike it with a hammer. Do not strike the vessel so hard as to pulverize the vessel, only enough to break it into several large pieces.
Sort each one of these large pieces into a unit on the grid.
Now break each of the larger pieces into smaller fragments and label each piece with the unit’s letter. Small fragments of the vessel will be lost as they are in archeological excavations.


Procedure

Have the students begin by sorting the sherds into the units. The sherds within each unit are likely to fit together, and the sherds from adjacent units may fit together. Encourage the students to talk about observable characteristics of the vessel fragments before they begin reconstructing the vessel.

Reconstruct pieces by finding two matching sherds (refit) and then place a thin line of glue on the entire length of both adjoining edges. Push sherds together, then pull apart and allow approximately 30 seconds for glue to become tacky. Fit sherds back together and hold them with slight pressure for 1 to 2 minutes, checking to make certain that curvature is correct. Then set vertically into rice box until completely dry; larger sections may take up to 2 hours to become fully set. Wipe excess glue from fitted sherds with a dampened paper towel or Q-tip.

Sherds that adjoin fit ‘like a hand and glove,’ but their edges may be deteriorated. Check the resulting curvature to verify a sherd match.

As larger sections come together, adjustments of curvature may be required to complete the pot. Exert slight pressure on the misaligned sections, and/or dampen the joins slightly so that the glue becomes flexible. To separate sherds that have been glued together, soak in water until they fall apart and scrub glue from the edges with a toothbrush.

Clues to matching the sherds include:

  • Pattern
  • Striations
  • Exterior color
  • Core color (on broken edges)
  • Thickness
  • Curvature
  • Matching rim fragments
  • With the vessel reconstructed, have the students discuss its attributes and make inferences regarding its age, function, and significance.