In order to understand how people lived in the past, archaeologists try to utilize tangible things (such as artifacts, chemical traces, human and animal bones, etc.). If anything was placed in the US 50 years ago or more ago, it is regarded as archaeological material.
Because archaeology works with the tangible whereas history only considers written documents, it differs from history (as in, the discipline that historians pursue). As a result, because writing was only developed relatively recently in human history, archaeology has a wider temporal range at its disposal (there are still non-literate cultures today). To attempt and understand what people did and how they utilized their objects—as well as how they thought about them and how they were used—because we lack records of these activities, we must instead employ experiments and comparisons to documented civilizations.
By knowing more about how people in the past lived, we may contribute to preserving elements of culture that have been lost or forgotten, gain life lessons about how societies and people work that we can use today, and even discover novel ways to address issues.
Thanks!
-Eddie