While it’s important to be faithful to Montessori tradition, it’s equally important for kids (and adults!) to realize that science evolves, new discoveries are being made all the time, and when it comes to scientific discussions, it’s best if we use the same terms so that we can be confident that we’re talking about the same things and we can make sure we’re all on the same page. Older Montessori materials use terms like “the archaic era” which is no longer scientifically accurate. Some Montessori albums further add that the archaic era is also called the proterozoic era, which is also incorrect. There is, however, an archean eon and a proterozoic eon, which refer to two different things. So, to make sure, that we are going to be using the best science available to us at present, we’re using the terms set by the ICS. You can see them in the geologic time scale below and in our worksheets.