4-ESS2-1: Weathering and Erosion
Also called NGSS 4-ESS2-1 · Topic: Earth's Systems: Processes that Shape the Earth · Earth and Space Science
The Official Wording
Make observations and/or measurements to provide evidence of the effects of weathering or the rate of erosion by water, ice, wind, or vegetation.
Clarification statement: Examples of variables to test could include angle of slope in the downhill movement of water, amount of vegetation, speed of wind, relative rate of deposition, cycles of freezing and thawing of water, cycles of heating and cooling, and volume of water flow.
Assessment boundary: Assessment is limited to a single form of weathering or erosion.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What 4-ESS2-1 Means in Plain English
Fourth graders observe and measure how water, ice, wind or plants break rock into smaller pieces, which is weathering, and carry those pieces away, which is erosion. They test one cause at a time, like steeper slopes or more shaking, and compare results.
Each investigation looks at a single kind of weathering or erosion, not all of them together. It builds on fast and slow Earth changes (2-ESS1-1) and prepares students for reading rock layers (4-ESS1-1) and for how water shapes land in middle school (MS-ESS2-2).
4-ESS2-1 I Can Statements
- I can explain the difference between weathering and erosion.
- I can test how moving water wears rock down.
- I can measure a change and use it as evidence.
4-ESS2-1 Worked Example
A shake-jar test a class can run at their desks to model how tumbling in a stream wears rock down.
Does more tumbling in water wear rock pieces down faster?
Set It Up: Three plastic jars with lids, water, classroom chalk broken into 3-centimeter pieces, a ruler and paper towels.
- Put two chalk pieces and the same amount of water in each jar.Sharp, square edges at the start
- Shake jar A 0 times, jar B 100 times and jar C 300 times.Water turns cloudy in B and C
- Pour off the water and let the pieces dry on a paper towel.Pieces from C look rounded
- Measure the length of each piece with a ruler.A: 3 cm, B: about 2.5 cm, C: about 2 cm
- Compare edges and lengths across the three jars.More shakes, smaller and rounder
The chalk shaken most came out smallest and roundest, and its water was cloudiest with tiny worn-off bits.
Why it works: Rocks tumbling in moving water knock and rub against each other, so bits break off and the water carries them away.
Common Mistakes with 4-ESS2-1
Mixing up weathering and erosion
“Erosion broke the rock.”
Try this: Weathering breaks rock into pieces where it sits. Erosion is the moving part, when water, wind or ice carries the pieces somewhere else.
Changing more than one thing
More shakes and warmer water in the same jar
Try this: Keep the water, jar size and chalk the same, and change only the number of shakes, so the result points to one cause.
Thinking rock is too hard to change
“Water can't hurt a rock.”
Try this: Water works slowly, but it keeps working. Over many years, rushing streams and freezing water crack and round even hard rock.
Where 4-ESS2-1 Fits
Practice 4-ESS2-1
Quick Check
- What is the difference between weathering and erosion?
- Why are stones in a river usually smooth and round?
- How can ice break a rock?