HS-ETS1-2: Breaking a Big Problem into Solvable Parts
Also called NGSS HS-ETS1-2 · Topic: Engineering Design · Engineering, Technology, and Applications of Science
The Official Wording
Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-ETS1-2 Means in Plain English
Students take a problem too big to solve in one step, such as getting clean water or power to a whole region, and split it into smaller problems. They solve at least one of those parts with a design they can build, test and improve.
Each smaller part keeps its own criteria and constraints, and the parts must still fit together into one working system. NGSS sets no extra limit on the problem chosen. It follows HS-ETS1-1 and leads to judging whole solutions in HS-ETS1-3.
HS-ETS1-2 I Can Statements
- I can break a complex problem into smaller design problems.
- I can solve one smaller problem with a design I test.
- I can explain how the parts fit back into one solution.
HS-ETS1-2 Worked Example
A design challenge a class can run on one piece of a real problem: keeping vaccines cold on the way to a remote clinic.
Which insulated box keeps vaccines between 2 and 8 °C the longest without electricity?
Set It Up: Three shoebox-size containers, frozen gel packs, small thermometers and three insulation choices: foam board, crumpled newspaper, and foam lined with foil.
- Break the big problem into parts: power, insulation, transport and temperature tracking.Four smaller problems on a tree diagram
- Choose insulation and set its criteria.Stay 2 to 8 °C, under 2 kg, under $10
- Load each box with the same gel packs, wrapped in cardboard so the vials never touch them.Same cold source, no freezing
- Log the temperature inside each box every hour.Hours spent inside 2 to 8 °C
- Improve the best box and retest it.Sealing lid gaps adds hours
Foam lined with foil held the safe range longest, and sealing the gaps around the lid added several more hours.
Why it works: Foam traps still air to slow conduction, foil reflects radiant heat, and sealing gaps stops warm air from flowing in.
Common Mistakes with HS-ETS1-2
Solving the whole thing at once
One giant sketch of a solar-powered cold truck
Try this: Map the problem into parts first, then pick one part small enough to build and test in class.
Losing the big picture
A perfect cooler that weighs 15 kg for a motorbike route
Try this: Check each part's solution against the whole system's constraints, like what a courier can carry, before calling it done.
Colder is always better
“Pack it with as much ice as possible.”
Try this: Many vaccines are damaged by freezing, so the design must keep the load inside the safe range, not just cold.
Where HS-ETS1-2 Fits
Practice HS-ETS1-2
Quick Check
- Why break a big engineering problem into smaller ones?
- A cooler keeps vaccines at 0 °C for a day. Does it meet the goal?
- How does a foil lining help an insulated box?