Deep Time

All this week, I’ve helped carry the flats of garden plants: out onto the deck in the morning, and back into the living room in the evening. This is the process called “hardening off” that we use to prepare plants for independent productivity. The learning we’ve been exposed to in iTeach feels somewhat like a hardening-off process. Will I take root and become productive in a distance-delivery mode with suitable digital-age skills to keep up with students?

On Thursday, we were exposed to questions of copyright, intellectual property, and hints of turmoil over this broad area of where ideas come from. This topic both fascinates and perplexes me.

I wanted to share with colleagues a difficult conceptual problem at the end of this iTeach experience: the depth of geologic time. How long has planet Earth been around? In a word, about 5 billion (with a b) years. In another term, about one-third as long as the universe has existed since the Big Bang, some 15 billion years ago.

Lots of attempts have been made to display the development of the Earth over time in a rational and memorable way. Students have a terribly hard time, judged by “evidence” and “assessments” grown out of “activities.” The last two times I have explored deep time, I’ve use the images below.

The point of this suite of images is the extraordinary length of time that it has taken for Earth to evolve to having a mantle of ocean, atmosphere and terrestrial systems teeming with multicellular life. Concurrently, students are meant to sense how recent or shallow our human footprint has been on the surface of this tapestry. In effect, one or two swipes of a fingernail file over your outstretched middle finger on the right hand remove the equivalent of 10 thousand years of written human history from this suite of images.

I’m at the point of converting these raw materials from what became a classroom Powerpoint image suite to something more appropriate to distance teaching. Everybody’s suggestions are most welcome.