Summary

In this lab, students will learn about what properties constitute soil and how it is different than “dirt.” Students will also be able to distinguish the difference between sand, silt, and clay.

Grade Level

Elementary School

NGSS Alignment

This lab will help prepare your students to meet the performance expectations in the following standards:

• 2-PS1-1: Plan and conduct an investigation to describe and classify different kinds of materials by their observable properties.

Objectives

By the end of this lab, students should be able to

• Differentiate between sand, silt, and clay.
• Determine (roughly) how much sand, silt, and clay make up the different soil samples used.
• Classify and distinguish between materials based upon their observable physical properties.

Chemistry Topics

This lab supports students’ understanding of

• Separating Mixtures
• Mixtures
• Physical properties
• Soil properties
• Observations

Time

Teacher Preparation: 30 minutes

Lesson: 90 minutes (and will need to record observations the following day as well)

Materials

(per group)

• Jars or clear bottles (with wide mouths)
  • They need lids or caps that are tight as you’ll be shaking the containers
  • Enough jars or bottles for each soil sample
  • Mason jars work well as do large juice bottles with the labels taken off
• Several cups of different soils:
  • One from the schoolyard, a garden, playground, etc. It would be ideal to have one very obviously sandy soil so the students can see the difference between particle sizes.
  • 2-5 soil samples are ideal. You can assign students to collect their own samples from their yard or playgrounds. They could fill up a quart Ziploc bag with their soil and that would be plenty.
• Water
• Stopwatches
• Labels for each sample
• Metric ruler (optional)

Safety

• Always wear safety goggles when handling chemicals in the lab.
• Students should wash their hands thoroughly before leaving the lab.
• When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.

Teacher Notes

• You can do this activity as a demonstration or give each group their own soil sample.
  • 3-5 students per group is suggested.
  • If using as a demo, students can still fill out the data form and record their observations.

• You can change the number of minutes or hours for the students to observe their soil layers, depending on your class schedule.
• Dirt is not synonymous with soil, something that many people do not know. Soil is vital to humans (not just farmers!) and is made up of minerals, air, water, and organic matter.
• After the students have recorded all of their data, and you don’t mind cleaning it up, you can have them feel the difference between the sand, silt, and clay layers.
  1. Use this video (for kids!) to teach about the basics of soil and plants, including what makes up soil.
  2. This short video of a soil scientist determining the soil profile in the field using colors can also be helpful to show students.
  3. Another helpful video to consider using is about the importance of soil and things that live in soil.
• The students can investigate one soil sample at a time, and after 5-minutes, they can move on to the next sample. Using stopwatches and recording the time when each sample is started is a good way to keep everything on track. Once the groups are finished with all of their samples, they can answer their analysis questions while they wait for the one hour mark to record their new observations.
• Update the data table given on the student document based on how many soil samples you plan to use.
• Answer Key for Pre-Lab Questions:
  1. Soil: minerals, air, water, organic material
  2. You could find: nematodes, worms, roots of plants, dead plants, bugs and insects, rocks, garbage/trash, fossils, etc. You could find a lot in soil and you can encourage your students to really think hard about what else could be in soil!
  3. It is important for soils to have different size particles so that air, water, and nutrients can flow through. Worms and other animals/insects can help aerate the soil, but they can only do that if there is already space: if a soil is mostly clay, it is virtually impossible for anything to flow through. Plant roots need space and they can’t grow through mostly clay soils. If the soil is too sandy, water and nutrients will slip right through and roots will not have anything to hold on to. You can encourage students to think about the beach of the ocean or a lake: are the plants on the beach itself? Why or why not?
  4. a. Sand
  5. c. Clay
  6. No, because if the sample has a significant amount of clay in it there won’t be enough space for plant roots, nutrients and water to move through it. Clay becomes very compact and tight due to its small size which makes it difficult for plants to grow or survive.
  7. Sand will settle first at the bottom since it’s the heaviest and biggest particles.

Two additional elementary school lab resources available in the AACT Resource Library that are focused on the chemistry of soil investigations are The pH of Soil and Soil Permeability.