Plastic Archeology

I've been designing injection molded plastic parts for various products for 30+ years. I'm not a materials scientist, but from what I've seen with plastics, there will be experts who will be able to date plastic archeology to a high degree of accuracy. The basic materials of things like polycarbonate or ABS may be fairly consistent, but the additives (plasticizers, lubricants, colorants, etc) seem to have a lot more change, specialization, and innovation over time. There's a constant push-pull of wanting the cheapest possible generic materials vs wanting performance, while the plastic companies need ways to differentiate their products to make it so that very specific grades get designed in. With the right technology (e.g. chromatography or mass spectrometry) the right industrial historians/chemists will be able to fingerprint plastic objects and date them.

As a chemist, I would guess that the guy tapping of the plastic on his teeth was a real assessment of the plastic. There are so many physical properties that are hard to describe, but still recognizable, and I do stuff like that all the time.

Contemporary archaeology - it's a thing: https://en.wikipedia.org/wiki/Contemporary_archaeology

Most famously, Bristol Uni excavated their own van: https://pages.vassar.edu/realarchaeology/2017/11/19/dismantl...

Addition related to LEGO and plastics - Lego abandons effort to make bricks from recycled plastic bottles - https://news.ycombinator.com/item?id=37673494

I once got some very very vintage Lego bricks which didn't survive the dishwasher! I wish I had thought twice about that because they were clearly pre-ABS.