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Worksheet Grade 4 Science

Water and the Shape of the Land: An Erosion Data Worksheet

A fourth-grade worksheet built on a class's soil-hill data, comparing slope and water flow to explain, then predict, real rates of erosion.

Objectives

  1. Read and compare a data table showing how much soil four hills lost under different slope and water-flow conditions.
  2. Explain how slope and the volume or speed of water flow each change the rate of erosion, using evidence from the data.
  3. Predict how a real, unvegetated slope above a creek would respond to a heavy rainstorm, based on the class's experiment.
  4. Describe why farmers and road builders take erosion data like this seriously when they plan how to use land.

Vocabulary

Erosion
Erosion is the wearing away and carrying off of soil and rock by moving water, wind, or ice. Fast-moving stormwater can strip soil from bare ground and stream banks.
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.

Also: slope, sediment, runoff

Teacher overview

Fourth graders often see erosion happen, in a muddy puddle after a storm or a gully cut into a dirt path, without always connecting the size of the erosion to the conditions that caused it. This worksheet addresses that gap by giving students data (invented but plausible) from a soil-hill experiment and asking them to reason from evidence rather than from a rule they memorized. The scenario deliberately varies two things at once, slope and the volume of water flow, because NGSS 4-ESS2-1 names both as example test variables, and separating their effects is the whole point of the exercise.

A common misconception to watch for: students often explain Hill D's heavy soil loss by saying "it's the steepest, so of course it lost the most," treating slope as the entire cause and forgetting that moving water is the agent actually doing the eroding in this standard. Question 7 confronts this directly by asking students to evaluate that exact claim against Hill B, a gentle hill that lost more soil than the steep hill under only gentle rain (Hill C). Watch for students who skip the comparison and answer from intuition instead of the table, which is the moment to have them point to the specific numbers.

The data are built for clean multiplicative patterns: changing from the gentle slope to the steep slope doubles the soil lost, and switching from gentle rain to heavy flow triples it, in both slope conditions. Strong students often notice this on their own by question 5, and it is worth naming explicitly during discussion, because recognizing that two variables can each have a consistent, separate effect is a sophisticated piece of science reasoning at this grade level.

Water and the Shape of the Land: An Erosion Data Worksheet — Grade 4 Science
Name: ____________________________ Date: ______________

Student Worksheet

The Experiment

Ms. Rowan's fourth-grade class at Cedar Hollow Elementary built four identical hills of packed potting soil in plastic trays, using the same amount of soil shaped the same way each time. Two hills were propped at a gentle slope (resting on one book) and two were propped at a steep slope (resting on four books). For each slope, one hill received gentle rain (water sprinkled slowly from a watering can for two minutes), and the other received heavy flow (four full cups of water poured quickly at the top all at once). A collection tray at the bottom of each hill caught the water and soil that washed down. After the water settled overnight, the class measured how much soil had collected in each tray.

Hill Slope Water added Soil collected in tray (cups)
A Gentle (1 book) Gentle rain (sprinkled, 2 minutes) 0.5
B Gentle (1 book) Heavy flow (4 cups, poured quickly) 1.5
C Steep (4 books) Gentle rain (sprinkled, 2 minutes) 1.0
D Steep (4 books) Heavy flow (4 cups, poured quickly) 3.0

Use the table to answer the questions below.

  1. According to the table, how much soil washed off Hill A? How much washed off Hill D?

  2. List all four hills in order from the least soil lost to the most soil lost.

  3. Hills A and B have the same slope but different water flow. How much more soil did Hill B lose than Hill A? Which variable, slope or water flow, caused that difference?

  4. Hills A and C received the same gentle rain but have different slopes. How much more soil did Hill C lose than Hill A? Which variable caused that difference?

  5. Compare Hill B to Hill D the same way you compared Hill A to Hill C in question 4 (same water flow, different slope). Does the steep slope multiply the soil loss by the same number both times? Use the numbers in your answer.

  6. Hill D lost more soil than any other hill. Using the words slope and volume of water flow, explain why Hill D lost so much more soil than any other hill.

  7. A student says, "Hill D lost the most soil only because it's the steepest hill." Is this a complete explanation? Use a comparison from the table to show what the claim leaves out.

  8. Predict: A construction crew clears all the grass and plants from a steep slope above a creek, and then a heavy rainstorm hits that same afternoon. Based on the experiment, predict what will happen to the soil on the slope and to the water in the creek. Support your prediction with evidence from Hills C and D.

  9. Why do farmers and road builders pay close attention to results like this experiment? Name one thing a farmer or road builder could do differently on a steep slope to protect the soil.

  10. The class wants to test a new question: does grass with roots reduce soil loss? Design a fifth hill, Hill E, to test it. What would you keep the same as one of the existing hills, and what would you change?

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

Answer Key

  1. Answer: 0.5 cup from Hill A; 3 cups from Hill D.
    Both values are read directly from the table.

  2. Answer: A, C, B, D (least to most: 0.5, 1.0, 1.5, 3.0 cups).
    Students should list the hills by their soil-collected values in increasing order.

  3. Answer: Hill B lost 1 cup more soil than Hill A (1.5 − 0.5 = 1 cup), caused by water flow.
    Hills A and B share the same gentle slope, so slope cannot explain the difference; only the water flow condition changed, from gentle rain to a heavy, fast pour.

  4. Answer: Hill C lost 0.5 cup more soil than Hill A (1.0 − 0.5 = 0.5 cup), caused by slope.
    Hills A and C both received the same gentle rain, so the extra soil loss must come from the steeper slope, which lets water move downhill faster and carry more soil with it.

  5. Answer: Yes, slope doubles the soil loss both times.
    Hill C lost twice as much as Hill A (1.0 is double 0.5), and Hill D lost twice as much as Hill B (3.0 is double 1.5). The steep slope's effect held steady whether the water flow was gentle or heavy, which is a sign of a real, dependable pattern rather than a coincidence.

  6. Answer: Hill D combines the steepest slope and the heaviest water flow, and each variable makes erosion worse on its own, so together they multiply. Steep slope alone roughly doubles soil loss (compare A to C, or B to D), and heavy flow alone roughly triples it (compare A to B, or C to D). Hill D has both conditions working at once, which is why its soil loss (3 cups) is far more than any single variable produced by itself.

  7. Answer: No, it is incomplete.
    Hill C is also the steepest slope, but with only gentle rain it lost just 1 cup, which is less than Hill B, a gentle hill, lost under heavy flow (1.5 cups). Steepness alone did not produce the most erosion; the amount and speed of the water moving over the soil mattered just as much. Without moving water, a steep hill in this experiment would not erode by this process at all.

  8. Answer: Heavy erosion is likely; a large amount of soil will wash into the creek.
    Clearing the vegetation removes any roots that might have held soil in place, similar to Hills C and D having no plant cover at all, and a heavy rainstorm matches the "heavy flow" condition that produced the worst erosion (Hill D, 3 cups) in the experiment. The soil that washes off the slope becomes sediment in the creek, which can cloud the water and cover the streambed where fish and insects live.

  9. Answer: Because losing topsoil and adding sediment to waterways causes real, costly damage.
    Farmers depend on topsoil to grow crops, and once it washes away it takes many years to replace naturally; road builders must keep loose soil from clogging storm drains and ditches or clouding nearby streams during and after construction. Accept any reasonable protective action, such as planting grass or cover crops on slopes, building terraces, or installing silt fences before grading a hillside.

  10. Answer: Answers will vary; a strong design changes only one variable.
    A strong Hill E keeps the same slope and the same water flow as one existing hill (for example, a steep slope with heavy flow, matching Hill D) but adds grass growing in the soil, changing only whether roots are present. Comparing Hill E's soil loss to Hill D's would then show whether roots reduce erosion, since every other condition stayed the same.

Differentiation

Support (below grade level)

Before assigning the full set, walk through the table together and have students circle the two numbers being compared in each question. Provide a sentence frame for the comparison questions: "Hill ___ lost ___ more cups than Hill ___ because ___ changed." Consider assigning questions 1, 2, 4, and 8 as the core set, saving questions 3, 5, 6, 7, and 10 for a second sitting or a small group.

Extension (above grade level)

The four hills lost a combined 6 cups of soil. Ask advanced students what fraction of that total came from Hill D alone (3 out of 6, or one half), then have them design a hypothetical Hill F that would lose even more soil than Hill D and justify the prediction using both variables from the experiment. Push further by asking what would happen if the class tested a slope steeper than any of the four books allowed. Would the doubling pattern definitely continue, or might it break down?

ELL supports

Pre-teach slope, erosion, sediment, and runoff using a quick labeled sketch of one hill and simple gestures (a flat hand tilted for slope, fingers "washing" downhill for erosion). Read questions 6 through 9 aloud before students answer in writing, and accept answers to question 9 that name one action without full sentences, since the science reasoning is the target skill, not sentence construction.

Extensions

Rebuild two of the four hills as a live demonstration using a dish tub, potting soil, and a watering can, and have students predict which hill will lose the most soil before you pour. If your school sits near a real slope, ditch, or stream bank, take a short supervised walk, keeping students well back from any water, to look for evidence of erosion in the schoolyard, such as a bare patch below a downspout or a rut along a path, and have students identify which of the experiment's two variables, slope or water flow, is most responsible for what they see.