Worksheet Grade 4 Science
Cloudy Water at Bright Pond: An Erosion Evidence Worksheet
A grade 4 worksheet using a fictional pond's weekly cloudiness scores as evidence of erosion, comparing rainy and dry days.
Objectives
- Students will compare cloudiness-score data from a pond across four days with different weather conditions.
- Students will calculate differences and totals from the data table using whole-number addition and subtraction.
- Students will explain, using the word erosion, why heavy rain on bare soil increases how cloudy nearby water becomes.
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.
Also: sediment, runoff, vegetation
Teacher overview
A class near the fictional town of Hartwell visits Bright Pond four times in one week and rates how cloudy the water looks each time, using a simple scale from 0 (crystal clear) to 10 (very cloudy). The pond sits below a bare dirt slope, so the class wants to know whether rain falling on that bare slope changes how the pond looks. This worksheet uses the class's own data table as evidence, the same kind of measurement-based reasoning a scientist uses to link a cause, like rainfall on bare soil, to an effect, like cloudier water.
Student Worksheet
Use this data table for every item. The class rated Bright Pond's cloudiness on a scale of 0 (crystal clear) to 10 (very cloudy).
| Day | Conditions the night before | Cloudiness score |
|---|---|---|
| Day 1 | Dry week, no rain | 2 |
| Day 2 | Light rain overnight | 5 |
| Day 3 | Heavy rainstorm on the bare dirt slope | 9 |
| Day 4 | Three sunny days after the storm | 3 |
Which day had the clearest water? Which day had the cloudiest water?
How much higher was Day 3's cloudiness score than Day 1's score?
What happened the night before Day 3 that most likely explains its high cloudiness score?
Use the word erosion. Explain why heavy rain on a bare dirt slope makes Bright Pond cloudier.
Find the difference between the Day 2 score and the Day 4 score.
Add all four days' cloudiness scores together to find the week's total.
Look at the whole week's scores. Is a score of 3 or a score of 8 closer to a typical day at Bright Pond? Use the data table to explain.
Suppose grass and plants covered the slope near Bright Pond instead of bare dirt. Would cloudiness scores be higher or lower after a rainstorm? Explain your reasoning.
Should the town keep checking Bright Pond's cloudiness after future storms? Give one reason from the data.
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: Day 1 clearest, Day 3 cloudiest.
Day 1 had the lowest score (2), and Day 3 had the highest score (9).Answer: 7.
Day 3's score (9) minus Day 1's score (2) equals 9 − 2 = 7.Answer: A heavy rainstorm on the bare dirt slope.
The table lists "heavy rainstorm on the bare dirt slope" as the condition the night before Day 3.Answer: Heavy rain erodes loose soil from the bare slope.
Rain hitting bare dirt washes, or erodes, loose soil downhill into the pond, and that washed-in soil is the sediment that makes the water look cloudy.Answer: 2.
Day 2's score (5) minus Day 4's score (3) equals 5 − 3 = 2.Answer: 19.
2 + 5 + 9 + 3 = 19.Answer: A score of 3.
Three of the four days scored 5 or below, and only Day 3's storm produced a score as high as 9, so a score of 3 fits the week's pattern better than a score of 8.Answer: Lower.
Grass and plant roots hold soil in place, so less soil would wash into the pond during a storm, which would keep the cloudiness score lower than it was on Day 3.Answer: Yes, with a reason from the data.
A complete answer says yes and supports it with a data detail, such as the large jump from Day 1's score of 2 to Day 3's score of 9 after a storm, showing that storms clearly change the pond's condition.
Differentiation
Support (below grade level)
Provide a number line from 0 to 10 for students to mark each day's score before comparing, and complete item 2 together as a class model before students work the remaining items independently.
Extension (above grade level)
Ask students to predict what Day 5's cloudiness score might be if a second heavy rainstorm hit the following night, using the pattern between Day 2 (light rain, score 5) and Day 3 (heavy rain, score 9) as evidence for their prediction.
ELL supports
Pre-teach erosion, sediment, runoff, and vegetation using a simple before-and-after sketch of a bare slope losing soil into a pond during rain, compared with a grassy slope. Allow items 3, 4, and 8 to be answered with a labeled sketch plus one short sentence rather than a full paragraph.