Lab / experiment Grade 6 Science

The Stannard Brook Stream Table: Slope, Sediment, and Runoff

A grade 6 lab in which students build a stream table, change its slope, and measure how far sediment travels and how cloudy the runoff becomes.

Grade: Grade 6
Subject: Science
Material: Lab / experiment
Time: 60 min
Prep: Moderate prep
Materials: Plastic tub or long baking pan, one per group, Sand and soil mixture, about 4 cups per group, Small aquarium gravel, about 1 cup per group, Pitcher of water, Measuring cup marked in milliliters, Plastic cup with a small hole punched in the bottom, Metric ruler, Three books of equal thickness, Two clear jars with lids, Sheet of white paper, Stopwatch or phone timer, Paper towels, Safety goggles

Standards

MS-ESS2-1 NGSS

Develop a model to describe the cycling of Earth's materials and the flow of energy that drives this process.

How this material aligns: The stream table serves as a physical model of how running water loosens, carries, and drops earth materials as the slope of the land changes.

All materials for MS-ESS2-1 →

6.SP.B.5 Common Core Math

Summarize numerical data sets in relation to their context, reporting the number of observations, describing the attribute measured, giving quantitative measures of center and variability, and relating the choice of measures to the shape of the distribution.

How this material aligns: Questions 1 and 2 have students report the mean of three measured travel distances in centimeters at each slope, and question 5 has them find the range of the high slope trials and say what it shows about how closely those trials agreed.

All materials for 6.SP.B.5 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will build a stream table model and change one variable, the slope, between trials.
Students will measure how far sediment travels and compare the mean distance at two slopes.
Students will explain how a stream sorts sediment by size as the water slows down.

Vocabulary

Deposition: Deposition is when water vapor in the air turns directly into ice without ever becoming liquid first, the way frost forms on a cold window. It is the opposite of sublimation, where ice turns straight into vapor.
Turbidity: Turbidity is a measure of how cloudy or murky water looks because of tiny particles floating in it. Clear water has low turbidity, and muddy water has high turbidity.

Also: stream table, slope, sediment

Teacher overview

Stannard Brook, a fictional stream, drops steeply out of the hills and then flattens out before it reaches the intake for the fictional town of Stannard, and the crew at the intake notices that the water turns brown after every hard rain. This lab asks how the slope of the land changes two things: how far sediment travels before it stops, and how cloudy the runoff becomes. Students build a small stream table, run water down it at two different slopes, and compare their results. The misconception this lab is built to correct is that fast water is cleaner water, since students often reason that a rushing stream washes dirt away and leaves clean water behind, when faster water in fact carries more material and larger pieces.

The Stannard Brook Stream Table: Slope, Sediment, and Runoff — Grade 6 Science

Name: ____________________________ Date: ______________

Procedure

Step 1. Set up the tray. Put on your safety goggles. Spread the sand and soil mixture in an even layer across one half of the tub. Pat it flat. Leave the other half of the tub empty. This empty end stands for the flat land near the town of Stannard.

Step 2. Add the gravel. Sprinkle the small gravel across the top of the sand layer. Spread it so you can still see sand between the pieces.

Step 3. Mark the start line. Use the ruler to draw a line in the sand across the top of the slope. Every trial starts at this line.

Step 4. Set the low slope. Place one book under the tub at the sand end. Measure the height of the raised end with the ruler and record it. This is your low slope.

Step 5. Run the low slope trials. Hold the cup with the hole over the start line. Pour 250 milliliters of water into the cup. Let it drain onto the sand. Start the timer when the water begins to run. When the water stops moving, measure how far the farthest visible sediment traveled from the start line. Record the distance in centimeters. Smooth the sand back flat and repeat two more times, for three trials in all.

Step 6. Collect a low slope sample. On the third trial, catch the runoff at the low end of the tub in a clear jar. Cap the jar. Label it low slope. Do not drink or taste any water from this lab.

Step 7. Set the high slope. Stack all three books under the same end of the tub. Measure the new height and record it. This is your high slope.

Step 8. Run the high slope trials. Repeat the pouring and measuring exactly as before, three more times. Use the same 250 milliliters of water each time. Smooth the sand between trials. Record each distance.

Step 9. Collect a high slope sample. On the third high slope trial, catch the runoff in the second clear jar and label it high slope.

Step 10. Compare and clean up. Gently turn each capped jar upside down twice so both start mixed. Hold the two jars side by side against a sheet of white paper. Let them stand for two minutes. Then answer the questions. Wipe up spills right away so the floor does not get slick, and wash your hands when the tub is put away.

Data & Analysis

Copy this table and fill it in as you work. Record every distance in centimeters.

Trial	Low slope distance (cm)	High slope distance (cm)
1
2
3
Mean

Record your three low slope distances. What is the mean of those three distances?
Record your three high slope distances. What is the mean of those three distances?
Compare your two means. Which slope carried sediment farther across the tub? Use both numbers in your answer.
Look at your two jars against the white paper. Which slope produced the cloudier runoff, and what do you see that tells you so?
Find the range of your three high slope distances by subtracting the smallest from the largest. What does a large range tell you about how alike your three trials were?
Look at where the gravel stopped and where the finest sand stopped. Explain what your model shows about how a stream sorts material by size.
Stannard Brook runs fast in the hills and slows down where it reaches the flat land. Use your results to explain what happens to the sediment in the brook when the water slows.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key

Answer: Accept any mean that matches the student's three recorded low slope distances.
Check the arithmetic rather than the value. Add the three distances and divide by 3. Typical classroom results fall between 8 and 20 centimeters, though tray length and sand moisture shift that range widely.
Answer: Accept any mean that matches the student's three recorded high slope distances.
Check the arithmetic the same way. The high slope mean should exceed the low slope mean for a correctly run trial set. If it does not, have the group check whether the sand was smoothed flat between trials.
Answer: The high slope carried sediment farther.
Accept any answer that states both means and says which is larger. A group whose data run the other way should still earn credit for reading their own data correctly, and should be asked to name one thing that may have gone wrong.
Answer: The high slope jar is cloudier.
Accept any answer naming the high slope jar and describing evidence such as a browner color, less light passing through, or more material still floating after two minutes.
Answer: Accept any range that matches the student's three high slope distances.
The range is the largest distance minus the smallest. A large range means the three trials did not agree well, which points to a variable that was not held steady, such as the pouring rate or how flat the sand was smoothed.
Answer: The gravel stopped first and the finest sand traveled farthest.
Look for the idea that heavier pieces need faster water to keep moving, so they drop out early, while light pieces stay in the moving water longer. Accept any answer describing that sorting pattern in the student's own words.
Answer: The sediment settles out where the brook slows down.
Look for the connection between slower water and less carrying power. Full credit also notes that the coarsest material drops first and the finest material travels farthest downstream, which is why the flat reach near town collects fine mud.

Differentiation

Support

Pre-build the tray for these groups so they begin at the start line step, and give them a data table with the trial numbers and units already entered. Provide a printed reminder card showing the mean as adding the three numbers and dividing by three, worked with a sample set that is not their own data.

Extension

Have these students run a third slope with two books and predict, before running it, whether the mean distance will fall between the low and high slope means. They should then graph all three means against slope height and describe the pattern the graph shows.

ELL supports

Pre-teach "slope," "sediment," and "deposition" using a picture sequence of a hillside, a moving stream, and a delta. Demonstrate step 5 silently in front of the class before groups begin. Provide sentence frames for questions 3, 6, and 7, such as "The ___ slope carried sediment farther because ___," and "When the water slows down, the sediment ___."

Extensions

Have groups repeat the high slope trials with the sand surface covered in a thin layer of moss, grass clippings, or shredded paper standing in for plant cover, then compare the new jar with the bare-sand jar. A written claim about how plant cover on the hills above the town of Stannard would change the brook makes a strong follow-up assessment.