MS-ETS1-4: Testing and Improving a Design with a Model
Also called NGSS MS-ETS1-4 · Topic: Engineering Design · Engineering, Technology, and Applications of Science
The Official Wording
Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What MS-ETS1-4 Means in Plain English
Students build a model of an object, tool or process, such as a scale model, a prototype or a computer simulation, and use it to collect data. They test, change one feature, and test again, using each round of results to move closer to the best design.
Models let engineers try ideas cheaply before building the real thing, and the model must test what matters for the real design. This builds on MS-ETS1-3 and leads to complex simulations in high school (HS-ETS1-4).
MS-ETS1-4 I Can Statements
- I can build a model that produces useful test data.
- I can change one feature and retest to improve a design.
- I can explain how each round of testing improved the design.
MS-ETS1-4 Worked Example
A scale model of a wheelchair ramp for the school stage, tested and redesigned over four rounds.
What ramp design lets a wheelchair user reach the 60 cm stage easily and still fits the space beside it?
Set It Up: A 1:10 scale model built from foam board and books, a small cart loaded with washers, a rubber band to pull it, and a ruler to measure the stretch.
- Round 1: build a ramp 6 cm high and 36 cm long, then pull the cart up it with the rubber band.Band stretches 4.5 cm
- Round 2: lengthen the ramp to 48 cm for a gentler slope.Band stretches 3.5 cm
- Round 3: lengthen it to 72 cm to meet the U.S. accessibility rule of 1 cm of rise per 12 cm of length.Band stretches 2.5 cm, but the ramp runs past the wall
- Round 4: fold the 72 cm into two 36 cm runs with a flat landing between them.Fits the space, band still 2.5 cm
- Roll the cart through the turn on the landing.Cart turns without bumping the edges
Each round lowered the pull needed, and the final two-run design kept the gentle 1-in-12 slope while fitting beside the stage.
Why it works: A gentler slope spreads the same rise over a longer distance, so less force is needed at each moment to move a wheelchair up it.
Common Mistakes with MS-ETS1-4
Changing everything each round
A new length, a new surface and a new cart in the same round
Try this: Change one feature per round and keep the rest the same, so you know which change caused the new result.
Stopping after one test
“The first ramp worked, so we're done.”
Try this: Keep testing until changes stop improving the results or the design meets every criterion, then explain why it is the best version.
Forgetting the model's limits
“The toy cart made it, so a real wheelchair will too.”
Try this: A model tests some things well, like slope, but not others, like grip or a person's strength, so note what it cannot show.
Where MS-ETS1-4 Fits
Practice MS-ETS1-4
Quick Check
- Why build a scale model before the full-size ramp?
- The stage is 60 cm high. How long must a 1-in-12 ramp be?
- Why did the team switch to two runs with a landing?