Soil Layers Jar Experiment

A large clear jar with a tight lid (a quart mason jar is perfect)

About 2 cups of garden soil from your yard

Water

A single drop of dish soap

A ruler for measuring layers

Paper and pencil for drawing a diagram

Go outside and dig up soil from your yard. Try to collect from two or three different spots — under a tree, in the garden bed, near the driveway. Different areas may have different soil compositions.

Fill the jar about one-third full with soil. Remove any large sticks, rocks, or roots.

Add water until the jar is nearly full (leave about an inch of space at the top). Add one drop of dish soap — this helps break up the clay particles so they separate cleanly.

Screw the lid on tight and shake vigorously for two full minutes. Your child will love this part. The mixture should look like brown milkshake.

Set the jar on a flat, stable surface and watch. Within minutes, heavy sand grains settle to the bottom. Over the next hour, lighter silt settles on top of the sand. Fine clay particles take longest — sometimes 24 hours to fully settle. Organic matter floats on top.

After 24 hours, measure each layer with a ruler. Draw a cross-section diagram showing sand, silt, clay, and organic matter. Label each layer.

Before shaking, ask your child to predict what will happen. Will everything stay mixed? Will it separate? What will sink first? Then compare predictions to results.

Compare soil from different locations. Soil from a sandy playground will look completely different from rich garden compost soil.

The proportions of sand, silt, and clay determine the soil type. Mostly sand = sandy soil. Mostly clay = clay soil. A good mix = loam (ideal for gardening).

This experiment takes patience. Set the jar somewhere visible and check it at intervals — after 10 minutes, 1 hour, 24 hours. The slow separation is the science.