The continuous expansion of scientific knowledge makes it nearly impossible to teach all of the pieces of a given science discipline to K–12 students. The role of science education is not to teach the memorization of facts, but to prepare students with core knowledge that they can build upon in the future.

Preparing students with a set of core ideas and practices allows them to continue their development as scientific learners, users of scientific knowledge, and—possibly—as producers of this knowledge.

Even though the NGSS have been around for some time, there can still be confusion around their dimensions. For this reason, a deep understanding of the three dimensions of the NGSS—and how they work together—is essential for developing instruction that proceeds coherently over time and allows students to build this rich conceptual framework.

Let’s walk through an overview of the three NGSS dimensions and their value to the teaching and learning of 21st-century science.

What is NGSS?

The Next Generation Science Standards (NGSS) have moved teaching science away from covering isolated facts and toward helping students build a rich network of connected ideas. This network serves as a conceptual tool for explaining phenomena, solving problems, making decisions, and acquiring new ideas.

The NGSS present standards as knowledge-in-use performance expectations, and each performance expectation integrates the three dimensions. In fact, each dimension works with the others to help students build a connected understanding of science as they progress through the grade levels.

Why was the NGSS scientific method needed?

Teachers may ask, Did we really need new science standards? What was wrong with the old ones?

The Next Generation Science Standards were necessary because the way students learn science needed improvement.

The creation of the NGSS and their implementation have required a shift in the way science is taught and learned. New standards were developed because innovative science education research has helped teachers deeply understand that students learn science by doing science.

Science is at the heart of the ability to:

• Innovate
• Lead
• Create jobs for the future

That’s why it’s so important for all students to have access to the highest quality science education.

The NGSS were released in 2013 and are being implemented in schools across the country. These standards are rich in practice and content. They are also arranged coherently across all grades and scientific areas of study.

What are the three dimensions of NGSS?

As noted earlier, the NGSS focus on three interrelated dimensions:

• Disciplinary Core Ideas (DCIs)
• Science and Engineering Practices (SEPs)
• Crosscutting Concepts (CCCs)

Let’s explore each of these dimensions in detail.

#1: Disciplinary Core Ideas (DCIs)

Disciplinary Core Ideas are the main ideas in science that are important across multiple engineering or science disciplines. The ideas build on each other as students learn more science at each grade level.

DCIs form the basis of what most educators would consider “content knowledge,” also known as scientific facts. DCIs are central to every science field and guide scientists and learners in:

• Observing
• Thinking
• Explaining phenomena
• Solving problems; and
• Asking/finding answers to new questions

These core ideas are organized into the NGSS’ four disciplines of science: Physical Science (PS), Life Sciences (LS), Earth and Space Sciences (ESS), and Engineering, Technology, and the Applications of Science (ETS). The NGSS advise that in order for an idea to be considered core, it “should meet at least two of the following criteria, and ideally all four:

• Have broad importance across multiple sciences or engineering disciplines or be a key organizing concept of a single discipline;
• Provide a key tool for understanding or investigating more complex ideas and solving problems;
• Relate to the interests and life experiences of students or be connected to societal or personal concerns that require scientific or technological knowledge;
• Be teachable and learnable over multiple grades at increasing levels of depth and sophistication.”

NGSS DCIs vs. previous standards: An example

DCIs are structured differently from how the previous standards were structured. Each DCI is a conceptual whole that helps to guide students’ thinking.

Each one also links to other DCIs to help students form a deeper understanding that they can use to make sense of the world around them. They move classroom teaching away from having students memorize a number of disconnected facts and concepts to a place where students develop a connected understanding of a few powerful concepts that they can use to make sense of the world and design solutions to problems.

Let’s look at an example comparing an older science standard to NGSS:

• Older science standard 1.a: Students know cells function similarly in all living organisms.
• NGSS – MS-LS1-2: Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.

In the NGSS performance expectation, students are called upon to show knowledge in one of the selected core ideas (or scientific facts) designated for Life Science at middle school grades 6–8 (e.g., knowledge of cell function and parts, such as nucleus, chloroplasts, mitochondria, cell membrane, and cell wall). That is the DCI.

The other two dimensions (SEPs and CCCs) are present in the performance expectation as well—as I’ll explain in the following sections.

#2: Science and Engineering Practices (SEPs)

Science and Engineering Practices explain how scientists investigate the natural world and how engineers design and build systems. SEPs explain in depth what inquiry means in regard to science and how it relates to physical, social, and cognitive practices.

Specifically, SEPs describe:

• The major practices that scientists employ as they investigate and build models or theories about the world
• A key set of engineering practices that engineers use as they design and build systems

The SEPs are not independent but rather overlap and work synergistically in classrooms. They can be grouped into 3 categories:

1. Investigating Practices: These focus on students asking questions, planning and conducting investigations, and using mathematical and computational thinking about the natural world resulting in the production of data.
2. Sensemaking Practices: These include the many ways that students can analyze and make sense of data while developing models and constructing explanations about the natural world.
3. Critiquing Practices: These are often left out of K–12 science education. Critiquing practices emphasize students evaluating and arguing about different models and explanations, which ultimately helps them develop a stronger understanding of the natural world. This category also includes Obtaining, Evaluating, and Communicating Information.

Fitting the SEPs together

It can be overwhelming to think about the SEPs, especially for those educators who are new to the NGSS. Essentially, students first use their investigating practices (asking questions, planning/conducting investigations, computational/mathematical thinking) to get their data.

Once they have data from the investigating practices, they are able to use their sensemaking practices to develop and use models, analyze and interpret the data, and start to construct explanations.

Now, with their explanations and/or models, they can focus on critiquing practices to engage in arguments based on evidence and obtain/evaluate/communicate information.

SEP example

Let’s return to our original example:

• Older science standard 1.a: Students know cells function similarly in all living organisms.
• NGSS – MS-LS1-2: Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.

This performance expectation integrates the Sensemaking Practice of Developing and Using Models.

The idea that standards can include both content (DCIs) and practices (SEPs) is not necessarily new. However, the third dimension of Crosscutting Concepts can take more getting used to.

#3: Crosscutting Concepts (CCCs)

Crosscutting Concepts reach across disciplines and help students explore connections between:

• Physical Science
• Life Science
• Earth and Space Science; and
• Engineering Design

CCCs provide students with a conceptual framework that helps them make sense of new content. CCCs emphasize the need to consider not only disciplinary content but also the ideas and practices that “cut across” the science disciplines.

When specific concepts—such as cause and effect—are explicitly explained to students, they can help lead to a logical and scientifically-based view of the world. In this way, CCCs serve as intellectual tools for connecting important ideas across different domains, and they provide students with an organizational framework based on behavior and function.

CCCs generally work together to provide clarity in making sense of a phenomenon. We can organize the CCCs into three categories:

1. Patterns: Patterns guide organization and classification. They prompt questions about relationships and the factors that influence those relationships. Identifying patterns helps scientists to identify phenomena and predict outcomes.
2. Systems: Systems provide students with a way to understand the interactions of a system’s components and the concepts that define it. Scale & Proportion, Change & Stability, and Matter & Energy fall into this category.
3. Causality: Causality is the central CCC. It is both the how and the why. Causality is the key to making sense of a phenomenon. Cause and Effect and Structure & Function fall under this group.

CCC example

When we return to our example, we see that the Crosscutting Concept of Causality (specifically Structure & Function) is used in the performance expectation:

• Older science standard 1.a: Students know cells function similarly in all living organisms.
• NGSS – MS-LS1-2: Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.

Why are the CCCs on equal footing with SEPs and DCIs?

To illustrate the importance of CCCs, let’s use an example from a cognitive psychology research study. It focused on the distinction between how expert and novice chess players organize ideas.

Chess experts and novices were shown pieces randomly arranged on a chess board. They were then asked to recreate the arrangement of pieces on the board from memory.

Novices tended to remember only individual pieces and their position in space. Experts, however, grouped pieces together based on the strategic moves that the piece could make in the game. The experts could then use this conceptual framework to organize and make sense of any configuration of pieces on the board.

In general, novices rely on surface features (isolated facts or formulas) to organize ideas, while experts develop and use a conceptual framework, sorting new knowledge using big ideas or broad categories. Sound familiar?

Using surface features like novices is the old way of learning science. Using a conceptual framework like the experts is the new NGSS way of learning science. CCCs help students think like experts by providing them with a conceptual framework around which they can build their understanding and new ideas.

NGSS performance expectations: Putting DCIs, SEPs, & CCCs together

To sum up, NGSS performance expectations integrate the three dimensions: DCIs, SEPs, and CCCs. Let’s look at our example one last time:

• Older science standard 1.a: Students know cells function similarly in all living organisms.
• NGSS – MS-LS1-2: Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.

We can now easily recognize each of the dimensions in the language of the new standard:

• DCI: LS1.A—“…describe the function of a cell as a whole and ways parts of cells…”
• SEP: Sensemaking Practices—“Develop and use a model…”
• CCC: Causality—“…contribute to the function”

Understanding the three dimensions of NGSS is a critical first step toward preparing students for NGSS performance expectations—but it’s only the beginning.

The Next Generation Science Standards require teachers and students to approach science learning in new and different ways. Using these three dimensions of science together, students will begin solving problems and making sense of phenomena.

How Renaissance supports NGSS implementation

Our DnA custom assessment platform includes a high-quality item bank and collection of pre-built assessments created by experts to yield results that you can use to drive classroom instruction.

DnA offers more than 80,000 items in core subject areas, including thousands of K–12 science items aligned to the three dimensions of the NGSS. DnA also provides a wealth of reporting options, including item distractor reports to help you identify learning disconnects and guide appropriate feedback.

Connect with an expert today to learn more about DnA and other tools from Renaissance to support student learning in science and mathematics.