What Floats to the Surface: Uncovering Traces of Daily Life through Soil.

Enoch Sey Koomson
7 days ago
2 min read

During the 2025 summer field excavations at Sylvester Manor, soil samples were taken from the site of the 19^th century dairy. While excavating units placed inside the dairy, the oldest layers of soil were found to have well preserved organic materials such as fish scales and fish bones in them. Soil samples were taken for flotation, an archaeological method used to recover small botanical and animal remains.

While this process can be done by hand, in NEAAAL, we used the flotation machine. This process involves placing water on one side of the machine and the soil sample on the opposite side which contains water aerators and a large, mesh screen

Graduate student Enoch Sey Koomson places a soil sample into the flotation machine.

As water flows through the fine mesh screen, small artifacts and plant and animal remains, also known as particulates, are left behind. The water must be continuously agitated for these items to appear! Heavy fraction particulates can include sediments and rocks, small bones, wood, or seeds. These items stay on the large mesh screen as the water is agitated by both aerators and hand. However, the light fractions, which can include charcoal or other types of burned material, will float up to the surface and be carried across the machine and into the fine mesh screen as the water drains through.

Here the water is agitated, and light fraction materials are caught on the fine mesh.

The water is drained through the fine mesh screen, leaving light fraction materials behind.

After all the soil has been agitated and no other particulates come up, the floating is done! From here, the particulates are dried and sorted. Flotation can help us learn about the natural environment. Archaeologists can answer questions about the types of food eaten by the people who occupied the site and reconstruct the ecosystem that they lived in.

Light and heavy fraction materials are placed on screens so they can dry and be sorted at a later time.