Archaeology is the study of human society. It is the recovery and analysis of cultural material and data left behind from various civilisations. The field of study is similar to finding the pieces of a puzzle and figuring out how they fit together to create the bigger picture. Originating in 15th-century Europe, archaeology began with the collecting of large art objects and historical artefacts from Greece and Rome. The systematic study of archaeology began in the 18th century. Many developments and improvements to field tools and methods occurred during this time. The archaeological community and museums began to set standards and rules for excavations of sites. One of the standard tools developed during this time is the sifting screen or sieve.
The sieve or sifter is a wire mesh screen used to strain or separate small pieces or artefacts from loose soil. Prior to the 19 century, screening was not widely practised. Screens were mostly coarse-mesh screens used to recover coins and beads. Today, archeologists use several grades of mesh screen to sift through the loose soil at a dig. By using a sifter, the archeologist will find the smaller pieces of broken artefacts that otherwise might be missed.
Many archaeologists prefer to design or create their own shifters, believing that different environments and situations require different methods and screen sizes for sifting debris. For sites that are hard to get to, archaeologists designed a screen that could attach to a backpack.
In many cases small flecks of bone and broken pottery are hard to find except through a double shifting process. The shifter is built with two sizes of screens. The screens are stacked with the larger screen mesh on top. As the dirt passes thorough the ¼-inch mesh, it is finally shaken through a 1/8-inch mesh screen.
Tripod and Rocker Screens
Larger screens hang from a tripod to make shifting of material easier by one person. Many times, the tripod is erected from poles found on-site. Rocking sifters are designed primarily for two people to use. As one person shovels dirt onto the screen, a second person shakes the screen. A single person, if necessary, can also use rocker screens.
A special type of screening called "flotation" excavates dirt from a large drum of water. The artefact material floats to the top as the water is poured off through fine-mesh screens. Flotation is effective for recovering remains of plants and seeds that are used to define what the people of the area hunted, grew or gathered to eat.