Papatūānuku and pūtaiao: the science of soil
Teens in Te Whanganui-a-Tara (Wellington) have been exploring the weird and wonderful world of worms and soil through a Māori lens.
Year 9-10 ākonga (students) at Te Kura Kaupapa Māori o Ngā Mokopuna in Seatoun have been digging holes, looking for noke (earthworms) and collecting soil samples from different areas of their school grounds.
The session was led by Sara Filoche at the University of Otago Wellington, as part of a regional project called Science Fusion, in partnership with Renee Campbell, Kaiako Pūtaiao Wharekura (secondary science teacher) at TKKM o Ngā Mokopuna.
Renee says that it is sometimes challenging for ākonga to transition from studying pūtaiao (the study of science from a Māori worldview) to pursuing non-Māori university science courses. So by putting university-recognised science topics in a Māori framework, Sara and Renee are trying to help bridge this gap.
The rangatahi first collected samples from the pū-wairākau (compost), pāmu noke (worm farm) and the school’s hangi pit and mahinga kai (food gardens).
The students also searched for noke at the same time. These animals play an important role in soil and plant health – as well as being used as bait in traditional fishing methods, such as those used to catch tuna (freshwater eels).
Once all the soil samples had been collected, they put a small amount of each sample into a measuring tube and added water to it.
They then shook the mixture together and then let it settle, before measuring the layers that emerged to work out what that soil sample was mostly made of. Some soils were mostly sand, while others contained more organic matter (dead plants that become soil) or ash.
Sara then showed the students a home-made purple-coloured pH (acidity) indicator that she had created from blueberry juice. The colour comes from a chemical called anthocyanin, which turns red in acidic environments and yellow in alkaline environments.
The students first added the blueberry juice to test tubes containing liquids they already knew were acidic or alkaline – lemon juice (acidic), vinegar (acidic) and dish detergent (alkaline) – to check that the blueberry juice would actually change colour.
“It was cool seeing how the colour changed,” says 13-year-old Deljah.
“I liked the control experiments most because they were easy to do and you can get the test ingredients anywhere”, adds Anitārewa, 14.
The students then tested their soil samples, with mixed success.
Some samples, such as from the pū-wairākau (compost), were too dark already to accurately compare any colour change against the reference chart Sara provided. The sample from the hangi pit, however, turned a visible green shade that suggested it was slightly alkaline.
“My favourite part was testing the soils, because it was hard to guess before we did the test how the colour might change,” says Tainui, 14.
Sara adds, “I’m not a soil scientist, so I also didn’t know what was going to happen. I was surprised at how green the hangi pit sample went, which I think might be because of all the ash in that soil.”
Afterwards, Sara pulled out a bucket of earthworms that she had found in her compost that morning in case they didn’t find any at the school.
Because the day was so hot and dry, the worms had indeed moved deeper underground to stay cool and damp. However the ākonga did manage to find one worm in the mahinga kai area.
After saying a karakia (prayer) for the worms, the ākonga then dissected two that had already died: one of Sara’s and the one they had found.
Because these were two different species, the rangatahi were able to compare the worms’ anatomy as well as get a better understanding of the mechanisms behind how worms improve soil quality by digesting it.
“I liked looking for the worms and learning about how they work,” says Wayne, 14. “We haven’t done anything like this before.”
About the project
Science Fusion is run by the University of Otago Wellington, with support from the Unlocking Curious Minds fund. This session was in partnership with Te Kura Kaupapa Māori o Ngā Mokopuna.
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