2-PS1-2: Choosing the Best Material for a Job
Also called NGSS 2-PS1-2 · Topic: Structure and Properties of Matter · Physical Science
The Official Wording
Analyze data obtained from testing different materials to determine which materials have the properties that are best suited for an intended purpose.
Clarification statement: Examples of properties could include, strength, flexibility, hardness, texture, and absorbency.
Assessment boundary: Assessment of quantitative measurements is limited to length.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What 2-PS1-2 Means in Plain English
Second graders test several materials and use the results to choose the one that fits a job best. To find the best spill rag, for example, they test how well each material soaks up water, then compare what the tests showed.
The only thing students measure with numbers is length, such as how many centimeters water climbs up a strip. Other properties, like strength or flexibility, are compared by observing. This builds on sorting materials by properties (2-PS1-1) and leads to the engineering tests in 3-5-ETS1-3.
2-PS1-2 I Can Statements
- I can test materials to see how well each one does a job.
- I can measure how far water climbs up a strip.
- I can use test results to explain my choice of material.
2-PS1-2 Worked Example
A soak-up test that helps a class choose the best cloth for wiping up spills in the art corner.
What material would make the best spill rag for the art corner?
Set It Up: Four strips the same size, cut from paper towel, a cotton dish towel, felt and a grocery bag, plus a clear cup of water with a drop of food coloring and a ruler.
- Tape the strips to a pencil resting on the cup rim so each bottom edge just touches the water.All four start wet at the same spot
- Wait five minutes and keep the cup still.Colored water creeps up some strips
- Measure how high the color climbed on each strip.Paper towel 6 cm, cotton 4 cm, felt 3 cm, bag 0 cm
- Draw a bar graph of the four heights.Paper towel bar is tallest
- Squeeze each wet strip to see if it holds together.Paper towel tears, cotton stays in one piece
Paper towel soaked up water fastest, but cotton was nearly as good and did not tear, so the class chose cotton for a rag they can wash and reuse.
Why it works: Water soaks into the tiny spaces between fibers, and a good choice looks at everything the job needs, not only one.
Common Mistakes with 2-PS1-2
Strips of different sizes
A long, wide paper towel strip next to a thin felt scrap
Try this: Cut every strip the same width and length so the only difference between them is the material being tested.
Judging on one test only
“Paper towel wins!” even though it falls apart when wet
Try this: List everything the job needs, like soaking up water and staying in one piece, then check each material against the whole list.
Measuring from the wrong spot
Measuring down from the top of the strip
Try this: Line the ruler's zero up with the water's surface and read where the color stops, the same way for every strip.
Where 2-PS1-2 Fits
Practice 2-PS1-2
Quick Check
- Why cut all the test strips the same size?
- Water climbed 6 cm on one strip and 2 cm on another. Which soaks up water better?
- A material soaks up water well but tears easily. Is it the best rag?