On Monday, I joined my son’s fourth grade class field trip to Pu’u Ualaka’a park near the top of Mount Tantalus in the Honolulu Watershed (the necessity for, and protection of, being a major point made throughout the day). Tantalus is a rather ominous name, but Pu’u Ualaka’a apparently means Hill of the Rolling Sweet Potatoes since the early Hawaiians grew them here and rolled the harvest downhill rather than carry it.
The program was put on by Hawai’i Nature Center and instructors Jaime and Randy did an awesome job. Randy showed the kids how water does and doesn’t get into underground aquifers and had them check biodiversity in the forest downhill from the photo. Everyone became forest rangers on a short hike designed to highlight some of the local plants and issues.
Jaime gave the best geology demonstration I’ve ever seen. We sat around a big map of the world with the Hawaiian islands conveniently placed in the center (wow do we look isolated out there in the middle of the Atlantic Pacific). She asked the kids how a boiled egg was like the earth and they knew that the yolk represented the core, the white the mantle, and the shell the crust — which brought us to tectonic plates. The kids had been studying all this in class, so they knew that earthquakes and volcanic activity happen at the edges of plates where they rub together. She had them place little flames on the map where most activity is and they recognized it as the Ring of Fire. But we’re in the middle of the plate. In the photo above, she’s showing us the theory of the hot spot in the center.
Here’s an island forming in the center of the hot spot (we’ll call it Ni’ihau)…
But tectonic plates move, so the little island on the plate gets pushed away from the hot spot and another one forms (Kaua’i) and then another (Oahu is moving slowly off the hot spot in the photo above). Lana’i, Molokai’i, Kahol’olawe and Maui bubbled up pretty close together, then comes the Big Island, Hawai’i — which is still sitting mostly on the hot spot and therefore active. What’s next? The kids proudly named Lo’ihi, a growing island still submerged.
Then it was time to replace the hot spot with a bit of ocean and build our island, Oahu. Here, two kids are using crushed lava rock to build the two shield volcanos that formed the island, Wai’anea and Ko’olau.
Then comes erosion from wind, waves and rain (the three girls above). At some point, rocks were added to represent the three smaller, but more explosive volcanos that formed Punchbowl, Diamond Head and Koko Head. Global warming brought a higher water level (kids poured in water from iceberg shaped containers) and coral formed around the island. The ice age lowered water levels again (sucked back up by turkey basters and returned to the icebergs) and soon we had a bowl of mud that resembled Oahu enough for the kids to recognize the Oahu Plain (where school is).
Jaime added some birds and plants grown from the seed they, or the wind and waves brought. Then came the Polynesians in that little stick canoe in the back, bringing pigs, chickens and more plants. Then came more people in modern times and built a different kind of house, added cars, and removed some trees and introduced some others. It was simple, but the kids were rapt with attention and really “got” the whole presentation.
Between creating an island, doing scientific experiments, and our ranger hike, and probably all that fresh air, the kids slept on the bus ride back to school! They all said it was a great field trip though. And I’ve signed up myself and my kids to participate this weekend in a Hawai’i Nature Center coastal walk where hopefully we’ll see many of the native plants my son has been learning about in school.