For this lesson, it will be necessary to enlist the help of a local geologist or driller. The goal is to find someone who can come in and show the children how to core into the ground. The core can be hand augured and go down several feet into the earth. When the auger is pulled out, a 2 inch diameter core of dirt layers can be seen. Students can see what is under their feet by looking at the core sample. The visiting driller or geologist may have other deeper core samples that they can share with students as well.
If you are unable to find a local driller/geologist to help you with this lesson, you may be able to obtain a 2 foot section of piping. You can have the students hammer it down into the ground at least a foot and then draw it out and push out the contents. The result will not be as layered, but at least students will be able to see down into the ground. You can do this in several spots to compare different soils.
While the Next Generation Science Standards are more about how plants use sunlight and water to grow, the soil is an integral part of the growth process. Young students need to be aware of the major influences on plant growth. According the the NGSS 2-ESS2-1 addresses that scientists need to study the natural world which is what they are doing in this lesson. This standard also addresses how things can change slowly or rapidly. If plants do not have adequate soil, their growth may be slow, but if the soil is rich, plants may change more rapidly. Students are seeing how both of these things are happening when they take part in this lesson.
I begin today by asking students, "have you have ever thought about what is under the ground outside?" I let students say yes or no and then ask, "What do you think is under the ground?" I expect some students to think of dirt and rocks, while others may think of books they have read about lava in the center of the earth. I let students share their thoughts.
"What do you think plants might need in the ground to help them grow?" (dirt, water, worms)
"Today we are going outside to look at what is under the ground in several places in the school yard. We have a special visitor who is going to help us. He is a geologist and he studies the rocks and water under the ground. He will come outside with us and share a special tool he uses to look at things under the ground. He will teach us how to use the tool and we will have a chance to see what is under the ground and think if that would be a good place for our plants (students have done several experiments with plants and have them to plant outside) to grow. (If you do not have plants from a previous lesson, you could buy a few plants or talk generally about what plants need to grow.)
I introduce the geologist to the students and say, "Does anyone have any questions about our visitor's job before we go outside?" I let students ask a few questions and then line them up to go outside. I tell them, "you have asked some good questions and there will be more time outside to ask even more questions as we see what our visitor does to study under the ground."
Once we are all outside, I ask the geologist to show us his special tool that he uses to study under the ground. He has a hand auger to show the students. I ask him if he can help us to see what is under the ground so we can find the best place to plant our flowers.
The geologist has the students help him turn the auger down into the ground.Coring Into the Ground When it is in, he shows students how he pulls it out and how it contains a long thin column of dirt in layers that are what is beneath us. After students look at the core, he spreads out a sheet and empties the contents onto the sheet. Removing the Core Students have a chance to look closely at all of the different types of soil, rocks, etc. This is not a very deep core so it will contain mostly dirt, but layers in the dirt may be obvious.
The geologist repeats the process at a different location, with students helping to do the turning of the auger.
After studying the two cores, Look What We Found the geologist shares with us several rock cores that he has done in the past. He explains how these were done with a machine auger that can go through rock and go much much deeper into the ground.
I give students plenty of time to ask questions and to look at the samples the geologist has brought.
After we have returned to the classroom, I ask students to share any thoughts about what we just did. I make sure everyone has a turn to speak.
I say to students after they are done, "now that you have looked at the two different areas outside, and have seen what is under the ground, which one do you think would be a better location for planting our flowers and why?" The why here is important, because students should now be at the point where they can state their opinion based on the information that they have gathered. I expect students to be able to discuss how one area was too sandy and the other had more dirt and worms, or that one area had too many rocks which would make it hard for the plants to grow, etc. I know that some students will also talk about the amount of sunlight which I will accept as important and tell them that sunlight is one thing we have learned a plant needs, along with fresh water and now, good soil to put the plant's roots in.
Once everyone has shared his/her opinion and reasons, and had a chance to respond to someone else's reasons, I ask for a vote of which area will we choose for our garden.
We schedule another day to take our plants outside and to plant them in our garden plot.
Bringing in a "real" scientist to work with the students is a way to get students excited about what science really is. The students all wanted a turn to turn the auger, and to remove the dirt from it. What was even more exciting was when we returned to the classroom with the dirt samples. students wanted to study them with a magnifying glass.
Before deciding where to plant, they wanted to show each other all that was in the ground in each location. They not only shared why we should plant in one location verses another, but they also went over to the samples and picked up evidence of too many rocks, old seed pods, bits of other roots as evidence as to why a certain spot was better for plants than the others.
Students went beyond what I asked, and really took ownership of the project as they studied, analyzed and then used their evidence to defend their choice of planting site.