Make an Excavation Block

Overview

This activity allows you to step into the shoes of an archaeologist. As you excavate a small block of plaster on the hunt for artefacts, be mindful of not just what you find but where you find it.

Background

Where you find an artefact, and the other objects it is associated with, can often give us clues about how they were used and how they were disposed of. They can also tell us about the place they were found, for example, what it was used for and how old it was.

Instructions

Sean Conley

Adult supervision is required.

Type of Activity : Crafting

How many people required (minimum) : 1

Safety Measures : An apron and gloves are recommended – mixing the plaster can get messy!!!
Take care not to inhale any of the plaster dust.

Ages : 8+

Time Required: 1-2 hours to prepare blocks, 20 to 40 minutes to excavate (depending on block size and softness)

Step 1

How to prepare the block: Use the bowl, container, water, Plaster of Paris, and spatula to prepare an appropriate amount of Plaster of Paris. Make sure you follow the instructions on the packaging and you can add in a bit of sand to create a more natural texture if you like. More water in the Plaster of Paris will make the finished block softer and easy to excavate while less water will make it harder.

Step 2

(Additional image from step 1).

Step 3

If your mould is something reusable like a bread or muffin tin, line it with cling film so that the block can be removed after it hardens. If the mould is disposable, like a small box or plastic cup, this is not necessary. You can simply cut the disposable mould off the block once it hardens.

Step 4

Pour a thin layer of the mixture into the bottom of your container.

Step 5

(Additional image from step 4).

Step 6

Drop an object into the setting plaster, that will act as your ‘oldest‘ artefact—a potsherd or bone. The closer it is to the bottom, the older it is. No plastic at this depth!

Step 7

On top of this layer, pour in more plaster to form a middle layer. Add a ‘younger’ artefact, perhaps a coin or bead.

Step 8

Pour in some more plaster to make the final layer and add in a plastic artefact. This will help signify that the layers on top are the most recent. If you want you can leave a portion of the plastic showing above the surface to show that there are artefacts to be discovered inside the block.

Step 9

Allow the plaster to dry. This should take about 1 to 2 hours, depending on the size of the block that you’re prepared. Once the plaster is dry, remove it or cut away the disposable mould. The block is ready to be excavated!

Step 10

How to excavate: Place your block on top of a protective surface, such as a plastic tablecloth or some newspaper.

Step 11

Take your clay tools or lollipop stick and begin to chip away at the block. Use your paintbrush to clear the block of dust if necessary. Start where you think an artefact might be and if you find one, keep going down in layers!

Step 12

When you find an artefact, keep track of what it was and in what order you found it. This is what an archaeologist would do in the field.