President Barack Obama sits with children during a tour of...

President Barack Obama sits with children during a tour of a Pre-K classroom at Powell Elementary School prior to speaking on the Fiscal Year 2015 budget in Washington, D.C., March 4, 2014. Credit: Getty Images

Fanning the firestorm over Common Core State Standards is the fear that by adopting common standards, states are signing onto a national curriculum and thus undermining the decisions of local school boards and educators.

But before going too far down that road, an important distinction needs to be made between standards - which outline what students should know and be able to do at each grade level - and curriculum - which is what happens day to day and week to week in classrooms. Standards remain constant, but curriculum can be altered year to year or classroom to classroom to ensure students are meeting the learning goals.

Let me illustrate with examples from three high-performing, high-poverty schools in three different states.

I asked them to share with me lessons they had developed to meet three of Common Core's reading and language arts standards, which say that fifth-graders should know how to:

-Use a dictionary and other reference materials.

-Identify the main ideas and supporting details of a text.

-Cite evidence to support an answer.

The first lesson, from George Hall Elementary in Mobile, Ala., is on the human circulatory system, part of a larger unit on major body systems, including the respiratory, excretory and reproductive systems. During the lesson, the teacher introduced particular terms the students would encounter in their reading, such as capillaries and white blood cells and asked the students to look up and record the definition of those terms in their science journals. Students then read "The Circulatory System," the fictional "A Journey through the Digestive System with Max Axiom," and consulted other non-fiction books. At the end of the lesson, students were asked to describe the function of the circulatory system in three to five sentences, citing evidence from the texts.

The second is from Finlay Elementary in Miami and is part of a three-week literature unit on " Hatchet," a story of wilderness survival. The teacher discussed the genre of realistic fiction with the students and then introduced vocabulary words such as hatchet, vibration and rudder. Students read along as the teacher read aloud, modeling fluent and expressive reading. Every couple of chapters, they wrote an analysis of the main ideas of the chapters along with the supporting details and an analysis of how the chapters fit together. This unit was paired with an environmental unit they were doing in science that culminated with a field trip to the Biscayne Bay where students learned about the kind of conditions in which the "Hatchet" protagonist found himself.

The third is from De Queen Elementary in southwestern Arkansas and is part of a large interdisciplinary English and science unit on the environment that has as its core question, "Why is it important to protect and preserve the Earth?" Before the students read "The River Ran Wild" by Lynne Cherry, a non-fiction account of the pollution and subsequent restoration of the Nashua River, teachers introduced vocabulary that students would encounter, with a focus on multisyllabic words with prefixes, suffixes, root words, and inflectional endings such as industrial and migration. After reading the book, they read about the Dust Bowl, which helped bring about the Great Depression, and other environmental effects of industry and farming. Students were then asked to write essays using complex sentences about Marion Stoddart, the woman who sparked the restoration of the Northeast's Nashua River in the 1960s.

This is just a taste of these lessons, which are much more nuanced and sophisticated than there is room to describe. And I should note that these are not the only lessons designed to help students meet those standards; kids don't learn complicated skills from one lesson.

But the point is that Common Core standards merely provide goals or benchmarks for learning to be filled by science, history, and literature lessons - all determined by local educators.

The idea behind the standards, which are in place in 43 states, is that no matter where students live or what their life circumstances may be, they should all have to meet the same expectations for learning - such as being able to use a dictionary and cite evidence from a text. Those common expectations can be met in a whole variety of ways, leaving all the most important decisions about curriculum, lessons and classroom activities in the hands of local schools and districts.

But by having a common set of expectations to measure their decisions against, school boards and educators will have a lot more information about how well they are serving all their students. That doesn't undermine them; it supports them.

Karin Chenoweth is writer-in-residence at The Education Trust, a national education advocacy organization, and author of "How It's Being Done: Urgent Lessons from Unexpected Schools."