NGSS Standard: 2-ESS1-1 — Use information from several sources to provide evidence that Earth events can occur quickly or slowly.
🎯 Learning Goals
Compare rocks by observable properties (color, texture, hardness, luster)
Observe how soil separates into layers when shaken with water
Understand that soil is made from weathered rock plus organic matter
📦 Materials
3-5 rocks collected from outside (any kind)
Magnifying glass (optional but recommended)
A coin and fingernail for hardness testing
Clear jar or plastic bottle with a lid
Soil from the yard (about 1/2 cup)
Water
Paper and pencil for recording observations
📖 Vocabulary
rockA hard, natural solid made of one or more minerals
mineralA natural, non-living solid material found in Earth's crust
soilA mixture of tiny rock pieces, water, air, and decomposed plants
textureHow something feels when you touch it (rough, smooth, bumpy)
lusterHow shiny or dull a rock's surface looks
sedimentTiny pieces of rock, sand, or soil carried and deposited by water
🔬 Background
Rocks are made of one or more minerals, the natural, non-living solid materials that make up Earth's crust. Rocks can be rough or smooth, shiny or dull, hard or soft, dark or light. Scientists called geologists study rocks to learn about Earth's history. Different types of rocks form in different ways: igneous rocks form when melted rock cools, sedimentary rocks form when layers of sediment press together, and metamorphic rocks form when heat and pressure change existing rocks.
Soil is not just dirt. It is a living mixture! It contains tiny pieces of weathered rock, water, air, and organic matter (decomposed leaves, plants, and organisms). Different soils have different textures. Sandy soil feels gritty and drains water fast. Clay soil feels smooth and sticky when wet. Rich garden soil (loam) has a mix of sand, silt, and organic matter and holds water well. The darker the soil, usually the richer it is in nutrients that help plants grow.
When you shake soil in water and let it settle, the heaviest particles (gravel and coarse sand) sink first. Then fine sand settles. Then silt. The lightest organic matter (bits of plant and leaf) floats on top. This experiment shows us the different layers that make up soil. Scientists call this soil stratification.
🧪 Activity: Rock Properties Chart & Soil Shake
Part 1: Rock Properties Chart
Step 1: Collect 3-5 rocks from outside. If possible, choose different looking rocks.
Step 2: Look at each rock carefully, using a magnifying glass if you have one.
Step 3: For each rock, record: Color (what color or colors do you see?), Texture (rough/smooth/bumpy?), Hardness (can your fingernail scratch it? can a coin scratch it? Note: fingernail = soft, coin = medium, cannot be scratched = hard), Luster (shiny or dull?).
Step 4: Write your observations in the Rock Properties Chart on the worksheet.
Part 2: Soil Shake
Step 5: Put about 1/2 cup of soil in the jar.
Step 6: Fill the jar about 3/4 full with water.
Step 7: Screw the lid on tightly and shake hard for 30 seconds.
Step 8: Set the jar on a flat surface and do NOT disturb it for 10 minutes.
Step 9: While waiting, draw what the jar looked like right after shaking (all mixed up and brown).
Step 10: After 10 minutes, observe the jar. Sketch what you see now. Note: the bottom layer is coarsest (gravel, sand), the middle is finer silt, and anything floating is organic matter.
💬 Discussion Questions
Q1: Why do different rocks feel different? What makes one rock smooth and another rough?
Hint: Smooth rocks were usually shaped by water. Rivers and waves tumble them over and over, wearing off the sharp edges. Rough rocks are freshly broken or have not been worn down yet. The minerals inside also affect texture; some minerals form smooth crystals and others form jagged grains.
Q2: Why does dark, rich soil grow better plants than pale sandy soil?
Hint: Dark soil has more organic matter (decomposed plants and organisms). This organic matter acts like food for plants and helps the soil hold water. Pale sandy soil drains too fast and has very few nutrients. Farmers add compost to sandy soil to make it more like rich dark loam.
Write the correct label next to each layer (from bottom to top): gravel, sand, silt, organic matter
Top (floating): _______________
Upper middle: _______________
Lower middle: _______________
Bottom: _______________
4. Fill in the blank
Soil is made from tiny pieces of _______________ rock plus _______________.
👩🏫 Parent/Teacher Notes
Rock selection: You really can use any rocks from outside. Gravel from a driveway, pebbles from a garden, rocks from a trail... all work fine. The goal is comparison, not identification.
Hardness test guide: A fingernail (hardness 2.5) can scratch talc and gypsum. A coin (hardness 3.5) can scratch calcite. If a rock scratches the coin, it is quite hard (probably quartz or feldspar).
Soil Shake timing: The layers take 10-30 minutes to settle fully. If your soil is very fine clay, it may stay cloudy for longer. That is okay. You can still discuss what is happening.
Organic matter tip: The organic matter floating on top can be hard to see if there is not much in the soil. If so, add a crumbled dry leaf to the jar before shaking.
✂️ PARENT ANSWER KEY
Worksheet Answers
Rock Properties Chart: Answers will vary based on rocks collected. Check that the child described each property (color, texture, hardness, luster) and that the descriptions are reasonable for what they observed.
Soil Shake Observations: "Right after shaking" should show a murky, mixed-up jar. "After 10 minutes" should show visible layers forming, with heavier material at the bottom and lighter material at the top.
Label the soil layers: Top (floating): organic matter. Upper middle: silt. Lower middle: sand. Bottom: gravel.
Fill in the blank: Soil is made from tiny pieces of weathered rock plus organic matter.
🥼
This is a preview. Unlock the full lesson.
You're seeing a preview. Full-library access is not live yet. For now, browse the live store products and free sample lessons while the larger subscription offer stays in Coming Soon. Live now: free samples + Kitchen Chemistry.