“With their four-dimensional minds, and their interdisciplinary ultraverbal way, geologists can wiggle out of almost anything.” – John McPhee
I love this quote about geology. Okay, it’s a bit of a backhanded compliment as it implies that geologists aren’t really proper scientists, “wiggling out of almost anything”. Nevertheless, it reminds me about what a great discipline it is. Firstly, geology can incorporate so many other disciplines (e.g. palaeontology, chemistry, physics and engineering). Secondly, in looking at a rock, or a mountain range, or any geological feature, geologists are not just looking at that three dimensional object, but they are always imagining what might have happened in the past (for it to have formed like that) and what might happen in the future.
The timescales on which these changes happen are not normal human timescales but frequently on the scale of millions or even billions of years. This vast timescale is often referred to as geological time, or Deep Time. Isn’t that pretty amazing?
In the first couple of classes this term I have been trying to expand my students’ minds, to encourage them to become four-dimensional thinkers.
The younger kids were left almost to their own devices to play with sand and water and a few pebbles, and then I came over to talk to them about the different ways that rocks can be eroded and landscapes can be transformed, using their sand structures to illustrate some of the different types of erosion.
I read to them from “Cracking Up” by Jacqui Bailey and Matthew Lilly.
This book tells the story of a cliff face and how some of the rocks from that cliff become broken off, ground down and transported to the nearby beach and end up as grains of sand. During the story we covered freeze-thaw erosion, erosion by sun, wind, rain and waves. The book also briefly mentions how the roots of plants can help to break up rocks. We further discussed how rocks get tumbled and their edges wear off to make them more rounded.
There is an experiment mentioned in the book where you can simulate the freeze-thaw process by putting one wet ball of clay in the freezer and keeping one at room temperature overnight. We haven’t tried this at home yet, but I will post pictures when I have.
There are also many wonderful rock formations all around Australia with shapes caused by erosion. I have a Steve Parrish book with some great illustrations of these.
In one group we discussed the Kiama blowhole, which certainly left an impression on my children when we visited a couple of years ago. We tried to model a blowhole with the sand and water, but the sand arch kept collapsing.
There is a lovely storybook about the Kiama blowhole: “The Great Rock Whale“, by Christine Pace and Wendy O’Malley. Some of your children may be interested in reading it or hearing it read aloud to them.
Our older groups have been pretending to be palaeontologists by trying to piece together bones from a xenosmilus skeleton, and identify what kind of creature it was. This was a difficult task and I could tell it was quite frustrating for some children.
I think I could have done some preparatory work looking at human skeletons, naming the bones and looking at the different types of joints, which would have helped when trying to identify and fit together the xenosmilus bones. For the second class, I prepared a picture of the complete skeleton so that the children could eventually match their bones to the picture and get it ‘right’.
Of course, in real life the likelihood is that the scientists would not have a complete skeleton and there could be years and years of disagreement about how exactly all the bones might fit together. But I can understand the need to complete the activity rather than leaving it hanging.
It seemed that the children also found it difficult to collaborate. I had split them into two teams for the purposes of collecting the ‘bones’ and they automatically assumed these teams would be in competition rather than trying to work together. It’s interesting to observe these interactions. I suspect it might help to think of other collaborative activities. I believe that science is best done in collaboration with other teams, rather than keeping your work secret and trying to be the team that ‘wins!’ Getting this across to the children might be harder than I thought.