The discipline of archaeology has changed dramatically since the time when average people were searching for strange or exotic objects. Today's archaeologists carefully excavate sites by recording the context and stratigraphic relationship of the objects they recover. Archaeologists are careful to take detailed notes during the entire process. When people continue to live in the same location for a long period of time, they build on the remains of those who lived there before, thus creating layers of remains that can be studied to learn how people lived and how they interacted with other groups. Excavation, however, is only part of the process of archaeology. Today the archaeologist may use techniques of the chemical or physical sciences to study materials used in the past and to determine where they were made and if they were brought into a site from somewhere else. Another approach is that of experimental archaeology where archaeologists attempt to recreate the objects of the past to understand the process by which the objects were made. Examples of experimental archaeology might be making tools (e.g., flintknapping) or by attempting to recreate some special type of pottery.