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Common Core LiteracyGrades 9–10Science & Technical

RST.9-10.6: Author’s Purpose and the Question Behind a Text

Also written as CCSS.ELA-LITERACY.RST.9-10.6 · Cluster: Craft and Structure.

All 29 Grades 9–10 Literacy Standards

The Official Wording

Analyze the author's purpose in providing an explanation, describing a procedure, or discussing an experiment in a text, defining the question the author seeks to address.

Common Core State Standards, Grades 9-10, Reading: Science & Technical Subjects · Read it at the source · Checked October 14, 2026

What RST.9-10.6 Means in Plain English

Ninth and tenth graders name the question a science writer is trying to answer, then explain how each part of the text serves it. In a report on brushed tomato seedlings, the identical lamps and watering are there to rule out every cause but touch.

In grades 6 to 8 (RST.6-8.6), students analyzed why an author explains, describes a procedure or discusses an experiment. Ninth and tenth grade add naming the question behind it. In grades 11 and 12 (RST.11-12.6), students also identify the issues the text leaves unresolved.

RST.9-10.6 I Can Statements

  • I can state the question a science text sets out to answer.
  • I can explain why the author includes a step or detail.
  • I can tell an explanation, a procedure and an experiment apart.

RST.9-10.6 Worked Example

The report describes a careful experiment on tomato seedlings, and the weak answer calls its purpose “to inform” without naming the question.

Read the Story
Seedlings started indoors often grow tall and spindly, while the same variety sown in a garden stays short and sturdy. Indoor seedlings get no wind, but they also get different light, water and temperatures, so which difference matters?To isolate movement, we grew 60 tomato seedlings on one bench in the school lab, under the same lamps, on the same watering schedule. Twice a day we ran a sheet of cardboard across the tops of 30 of them, bending each stem about ten times. The other 30 were never touched.After four weeks, the brushed seedlings averaged 18 centimeters tall and the untouched ones 25. The brushed stems were also thicker and bent less under a 50-gram weight.Because light, water and temperature were the same for both groups, the brushing is the likeliest cause. Biologists call this response to touch and bending thigmomorphogenesis, and some vegetable nurseries brush transplants on purpose so they survive the move to the field.
A short passage written for this page.
Question: What question is the author trying to answer, and why does the author describe the lamps and the watering schedule so carefully?
Not Yet“The author’s purpose is to inform readers about tomato plants and how to grow them. The author describes the lamps and the bench to give background.”“To inform” fits almost any science text, and how to grow tomatoes is not the question here. It reads the controls as background and misses that the author includes them to rule out light, water and temperature.
Meets the Standard“The author is asking whether movement alone makes plants grow shorter and sturdier, apart from the light, water and temperature differences between seedlings started indoors and seedlings in a garden. The first paragraph sets up that question by listing the differences and asking ‘which difference matters?’ The author stresses that both groups grew ‘under the same lamps, on the same watering schedule’ so brushing is the only difference left, which is why the last paragraph can call it ‘the likeliest cause.’ The ending adds a practical purpose: nurseries can use the answer to toughen transplants.”It states the question in the author’s terms, explains each procedural detail by the job it does for that question, and names the practical purpose the ending adds.
Question Stems to Use
What question does the first paragraph raise? Write it as a question.Why might the author include this step of the procedure?Which detail rules out another explanation?Is the author explaining, giving a procedure or discussing an experiment here? Why?Who could use the answer, according to the text?

Common Mistakes with RST.9-10.6

Settling for “to inform”

“The author’s purpose is to inform readers about plants.”

Try this: Have students finish the sentence “The author wants to know whether…” and check that every paragraph helps answer it.

Reading controls as background

“The author describes the lamps to set the scene.”

Try this: Ask students what explanation each procedural detail rules out, and have them star any detail they cannot yet connect to the question.

Confusing the topic with the question

“The question is about tomatoes.”

Try this: Have students rewrite the topic as a yes-or-no question the experiment could answer, then check that the results paragraph answers it.

Where RST.9-10.6 Fits

Comes BeforeRST.6-8.6Analyze why an author explains a concept, describes a procedure or discusses an experiment.
AlongsideRI.9-10.6Determine an author’s point of view or purpose and how the rhetoric advances it.WHST.9-10.7Run a short research project to answer a question, narrowing or broadening the inquiry as needed.
Comes NextRST.11-12.6Analyze an author’s purpose and identify the important issues that remain unresolved.

Practice RST.9-10.6

Quick Check

  1. What question is the experiment designed to answer?
  2. Why does the author stress that both groups had the same lamps and watering schedule?
  3. What practical use does the last sentence give the answer?

RST.9-10.6: Other Names

RST.9-10.6CCSS.ELA-LITERACY.RST.9-10.6

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.