HS-ESS2-1: How Land and Seafloor Features Form
Also called NGSS HS-ESS2-1 · Topic: History of Earth · Earth and Space Science
The Official Wording
Develop a model to illustrate how Earth’s internal and surface processes operate at different spatial and temporal scales to form continental and ocean-floor features.
Clarification statement: Emphasis is on how the appearance of land features (such as mountains, valleys, and plateaus) and sea-floor features (such as trenches, ridges, and seamounts) are a result of both constructive forces (such as volcanism, tectonic uplift, and orogeny) and destructive mechanisms (such as weathering, mass wasting, and coastal erosion).
Assessment boundary: Assessment does not include memorization of the details of the formation of specific geographic features of Earth’s surface.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-ESS2-1 Means in Plain English
Students model how Earth's features take shape when building forces and wearing-down forces work together. Volcanoes, uplift and colliding plates raise mountains, plateaus and seamounts, while weathering, landslides and erosion carve valleys and coasts, some in minutes and others over millions of years.
Students explain the processes, not the formation history of particular named features. The standard grows from middle school work on surface change at many scales (MS-ESS2-2) and connects to the convection driving plates in HS-ESS2-3.
HS-ESS2-1 I Can Statements
- I can name processes that build up and wear down land.
- I can explain how one landform reflects both kinds of process.
- I can compare how fast different surface processes work.
HS-ESS2-1 Worked Example
A tabletop model that squeezes layers into mountains and then wears them down.
What happens to flat layers of sediment when two plates push together, and what happens to the mountains afterward?
Set It Up: A clear plastic box, a wooden board as a sliding wall, alternating layers of sand and flour, and a spray bottle of water.
- Spread three thin layers of sand separated by flour so each layer shows from the side.Flat stripes, like sedimentary rock
- Push the board slowly 5 cm into the layers and look through the side of the box.Layers bend into folds and stack along slanted faults
- Measure the tallest peak, then push another 5 cm.Peak grows from about 2 cm to about 4 cm
- Mist the peaks with the spray bottle for one minute.Sand slides off the steep sides and fans out at the base
- Compare time scales: real uplift of a few millimeters a year for millions of years, versus a landslide in minutes.Slow building, fast and slow wearing down
Squeezing the layers built folded, faulted peaks, and the water began wearing them down and moving sediment downhill as soon as they rose.
Why it works: Collisions thicken and lift the land over millions of years while weathering and erosion attack it the whole time, so a mountain's shape records the balance between the two.
Common Mistakes with HS-ESS2-1
Treating mountains as permanent
“Mountains stay the same once they form.”
Try this: Erosion works on mountains from the moment they rise. Without continued uplift, even tall ranges are worn down to low hills over time.
Forgetting the seafloor has landforms
A model that shows features only on land
Try this: The ocean floor has ridges, deep trenches and underwater volcanoes too, built and worn by the same kinds of processes as land.
Assuming all change is slow
“Erosion takes millions of years, every time.”
Try this: Some changes are slow, like uplift of a few millimeters a year, but a landslide or eruption can reshape land in minutes.
Where HS-ESS2-1 Fits
Practice HS-ESS2-1
Quick Check
- Name one process that builds land and one that wears it down.
- Why are old mountain ranges usually lower and more rounded than young ones?
- If a range rises 3 mm a year with no erosion, how long until it is 3 km higher?