Elephant Rocks

Students explore the massive, spheroidally weathered boulders at Elephant Rocks State Park.
Students explore the massive, spheroidally weathered boulders at Elephant Rocks State Park.

We stopped at the Elephant Rocks State Park our way down to Eminence MO for our middle school immersion trip. The rocks are the remnants of a granitic pluton (a big blob of molten rock) that cooled underground about 1.5 billion years ago. As the strata above the cooled rock were eroded away the pressure release created vertical and horizontal cracks (joints). Water seeped into those joints, weathered the minerals (dissolution and hydrolysis mainly), and eroded the sediments produced, to create the rounded shapes the students had a hard time leaving behind.

This was a great stop, that I think we’ll need to keep on the agenda for the next the next trip. I did consider stopping at the Johnson’s Shut-Ins Park as well, but we were late enough getting to Eminence as it was. Perhaps next time.

Exploring the spaces between the rocks.
Exploring the spaces between the rocks.

Relativity in a Canoe

The world moves around the canoe.
The world moves around the canoe.

Perhaps not surprisingly, my middle school students have a difficult time wrapping their heads around the idea of multiple frames of reference. We were in a canoe on the Current River and I asked the student paddling in the rear of the boat to look at me and answer the question, “Are we in the canoe moving, or are we steady in one spot and everything around us moving?”

This resulted in some serious cognitive processing. And she still has not gotten back to me with an answer.

Another student, faced with the same question, thought it over overnight and concluded that it was a riddle. He figured the correct answer was that the canoe was moving and the land was still. I asked him to think about it a little more (because he was only half right).

Interestingly enough, I’ll be teaching my Advanced Physics class this block, and the first chapter has a neat little section on coordinate systems. I’m curious to see if the 11th and 12th graders have an easier time with the concept.

The canoe moves.
The canoe moves.