Clay, Sand, and Silt
Lesson 2 of 8
Objective: SWBAT describe the three types of soil and properties of each.
In this lesson, students add a scoop of soil to a jar and fill it with water, shake, and watch as the soil settles into different layers of clay, sand, and silt. This lesson aligns to Essential Standard 1.E.2.1, "Summarize the physical properties of Earth materials, including rocks, minerals, soils and water that make them useful in different ways". I post an essential question for each lesson. Today's question is: What are three types of soil? How can I tell them apart?Listen to my Explanation of Essential Standards and Essential Question.
For more information for teachers on soil testing and the types of soil, check out this website.
*Clear jars with lids - 1 for each 3-4 students so they can easily see the contents as they settle. Plastic peanut butter or mayo jars work well.
*1 large scoop of soil (not potting soil) per jar.
*Small sample of clay, sand, and silt (separated from the soil for the jars)
To start this lesson, first we make a prediction (like good scientists always do!). I say,
"Today, we are going to answer the question 'What are three types of soil, and how can we tell them apart?' So, to do this, soil scientists have two ways that we are going to try today. First, they do a jar test. I am going to show you how to do it and then it takes a while to settle. As it settles, we will try the other tests, and then we can check back on it, okay?"
I show my students how to put the soil into the jar, add the water, put the lid on tightly and let the teacher check it, and then let each person in the group shake it up. I show them how to do this instead of letting them do it by themselves because this is just one piece of this lesson - the real payoff comes after the contents of the jar have settled and we can see the different types of soil in the jar. By modeling how to make the jar it is a quicker process and I can make sure everyone has all three kinds of soil in their jar so that the end result is more meaningful to the lesson.
After I have made my soil jar, I say,
"Now, each group is going to make a soil jar to see what type of soil they have. After you have made it and shaken it, on your next page in your journal you have 2 outlines of jars. On the first jar, please draw exactly what you see, then stop!"
I help the groups to put together their soil jars and then make sure everyone uses accurate colors to record their observations, supporting Science and Engineering Practice 4. Then I say,
"Now, scientists ask questions, but they also make predictions which means to make an educated guess at what is going to happen. In the next jar outline, take 2 minutes and draw what you think is going to happen".
Making predictions based on prior experience (and every first grader has prior experiences with soil from gardening, playing outside, or just from kindergarten!) supports Science and Engineering Practice 3. As the students work, I listen for interesting comments or observations that I can bring into our group discussions later. Then, I ask everyone to leave their jars and come to the carpet with their journals.
As the soil in the jars settle, I take the time to really teach about the three soil types. I start an anchor chart titled "Three types of soil" and ask my students to copy in their journals. When they take notes it keeps them focused and they also have a record of the things that we have talked about. As I write on the anchor chart, I say,
"There are three types of soil that we are going to focus on: clay, sand, and silt. Loam is a mixture of the three. Soils are different because of the size of the particles that make them up. We are going to look at a website and draw a diagram together that will help explain it- you draw it too, in your journal, so you can remember what we talked about today".
We look together at this website and I add the diagrams under the labels on the anchor chart.
Then I say,
"Other than the jars, another way that soil scientists identify different types of soil is by testing it with their hands. They call this 'soil typing'. We are going to watch a quick video that will show us how this is done".
I show this video and afterwards I ask have a few volunteers help to model the method for the class. Since my students already did the soil jars in this lesson, I chose to have just a few students try out the second method in order to get so much into one lesson!
After we have tried that, I say,
"Now, your soil jars have probably settled. If you rush back to your tables and knock them off, they will have to settle again and you will not be able to finish your work. Please be careful when you go back. Do not touch the bottles. Go back and sit carefully - just look and do not touch them please!"
When everyone gets back (safely, hopefully!) I say,
"Now, you have one final jar outline on the next page of your journal that is a little bit bigger so you can draw a little more detail. Try to identify the sand, silt, and clay from what we talked about and label them if you can. I will be around to help you as well. Again, please do not touch your jars!"
I want students to correctly identify the types of soil, so I help them as they work and refer them back to the anchor chart when necessary. Recording information from observations of the natural world supports Science and Engineering Practice 4.
At the end of the lesson, I ask students whether their predictions about the jars were correct or not, which supports Science and Engineering Practice 4, comparing predictions to what occurred. I ask them to write in their journal (and I model on the board) "My prediction was __________ because ____________" in order to give a reason for their statement. Then, we share what we wrote together about the predictions which supports Practice 8, communicating information about ideas.