Research on learning shows that to develop a coherent understanding of scien- tific explanations of the world, students need sustained opportunities to engage in the practices, work with the underlying ideas, and appreciate the interconnec- tions among these practices and ideas over a period of years, not weeks or months (National Research Council, 2007). Researchers and science educators have applied this insight into how students learn in descriptions of the way understand- ing of particular content matures over time, called learning progressions. Learning progressions may provide the basis for guidance on the instructional supports and experiences needed for students to make progress (as argued in Gotwals and Songer, 2013; Corcoran et al., 2009; National Research Council, 2007; Smith et al., 2006).
Learning progressions are anchored at one end by what is known about the concepts and reasoning students have as they enter school. At the other end, learning progressions are anchored by societal expectations about what students should understand about science by the end of high school. Learning progres- sions describe the developing understandings that students need as they progress between these anchor points—the ideas and practices that contribute to building a more mature understanding. They often also address common misunderstand- ings and describe a continuum of increasing degrees of conceptual sophistication that are common as students if they are exposed to suitable instruction (National Research Council, 2007).
The framework builds on this idea by specifying grade-band endpoint tar- gets at grades 2, 5, 8, and 12 for each component of each core idea. The grade- band endpoints are based on research and on the framework committee’s judg- ments about grade appropriateness. Most of the progressions described in the NGSS (which are based on the endpoints described in the framework) were not primarily based on empirical research about student learning of specific mate- rial because such research is available only for a limited number of topics (see
BOX 2-2
EXAMPLE OF A PERFORMANCE EXPECTATION IN THE NGSS: MATTER AND ITS INTERACTIONS FOR STUDENTS IN 2ND GRADE
2-PS1 Matter and Its Interactions
*The performance expectations marked with an asterisk integrate traditional science content with engineering through a Practice or Disciplinary Core Idea. The section titled “Disciplinary Core Ideas” is reproduced verbatim from A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas. Integrated and reprinted with permission from the National Academy of Sciences.
Students who demonstrate understanding can:
2-PS1-1. Plan and conduct an investigation to describe and classify different kinds of materi- als by their observable properties. [Clarification Statement: Observations could include color, texture, hard- ness, and flexibility. Patterns could include the similar properties that different materials share.]
2-PS1-2. Analyze data obtained from testing different materials to determine which materi- als 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.]
2-PS1-3. Make observations to construct an evidence-based account of how an object made of a small set of pieces can be disassembled and made into a new object. [Clarification Statement: Examples of pieces could include blocks, building bricks, or other assorted small objects.]
2-PS1-4. Construct an argument with evidence that some changes caused by heating or cool- ing can be reversed and some cannot. [Clarification Statement: Examples of reversible changes could include materials such as water and butter at different temperatures. Examples of irreversible changes could include cooking an egg, freezing a plant leaf, and heating paper.]
Science and Engineering Practices
Planning and Carrying Out Investigations
Planning and carrying out investigations to answer questions or test solutions to problems in K-2 builds on prior experiences and progresses to simple investigations, based on fair tests, which provide data to support explanations or design solutions.
• Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence to answer a question. (2-PS1-1)
Analyzing and Interpreting Data
Analyzing data in K-2 builds on prior experiences and progresses to collecting, recording, and sharing observations. • Analyze data from tests of an object
or tool to determine if it works as intended. (2-PS1-2)
Disciplinary Core Ideas
PS1.A: Structure and Properties of Matter
• Different kinds of matter exist and many of them can be either solid or liquid, depending on temperature. Matter can be described and classified by its observable properties. (2-PS1-1) • Different properties are suited to
different purposes. (2-PS1-2, 2-PS1-3) • A great variety of objects can be
built up from a small set of pieces. (2-PS1-3)
PS1.B: Chemical Reactions
• Heating or cooling a substance may cause changes that can be observed. Sometimes these changes are reversible, and sometimes they are not. (2-PS1-4)
Crosscutting Concepts
Patterns
• Patterns in the natural and human- designed world can be observed. (2-PS1-1)
Cause and Effect
• Events have causes that generate observable patterns. (2-PS1-4) • Simple tests can be designed to gather
evidence to support or refute student ideas about causes. (2-PS1-2)
Energy and Matter
• Objects may break into smaller pieces and be put together into larger pieces, or change shapes. (2-PS1-3)
Connections to Engineering, Technology, and Applications of Science
Influence of Engineering, Technology, and Science on Society and the Natural World
• Every human-made product is designed by applying some knowledge of the natural world and is built using materials derived from the natural world. (2-PS1-2)
Constructing Explanations and Designing Solutions
Constructing explanations and designing solutions in K-2 builds on prior experiences and progresses to the use of evidence and ideas in constructing evidence-based accounts of natural phenomena and designing solutions.
• Make observations (firsthand or from media) to construct an evidence-based account for natural phenomena. (2-PS1-3)
Engaging in Argument from Evidence
Engaging in argument from evidence in K-2 builds on prior experiences and progresses to comparing ideas and representations about the natural and designed world(s).
• Construct an argument with evidence to support a claim. (2-PS1-4)
SOURCE: NGSS Lead States (2013). Copyright 2013 Achieve, Inc. All rights reserved. Available: http://www.nextgenscience.org/2ps1-matter- interactions [March 2014].
Corcoran et al., 2009).6 Thus, the framework and the NGSS drew on available research, as well as on experience from practice and other research- and practice- based documents (American Association for the Advancement of Science, 2001, 2007; National Research Council, 1996). The NGSS endpoints provide a set of initial hypotheses about the progression of learning for the disciplinary core ideas (National Research Council, 2012a, p. 33). An example, for ideas about how energy for life is derived from food, is shown in Box 2-3.
For the practices and crosscutting concepts, the framework provides sketches of possible progressions for learning each practice or concept, but it does not indicate the expectations at any particular grade level. The NGSS built on those sketches and provide a matrix that defines what each practice might encom- pass at each grade level, as well as a matrix that defines the expected uses of each
6The American Association for the Advancement of Science (2001, 2007) is another source
of progressions of learning that are based on available research supplemented with expert judgment.
BOX 2-3
LEARNING PROGRESSION FOR FOOD IDEAS ACROSS K-12 Grades K-2: Animals obtain food they need from plants or other animals. Plants need water and light.
Grades 3-5: Food provides animals with the materials and energy they need for body repair, growth, warmth, and motion. Plants acquire material for growth chiefly from air, water, and process matter and obtain energy from sunlight, which is used to maintain conditions necessary for survival.
Grades 6-8: Plants use the energy from light to make sugars through photosynthesis. Within individual organ- isms, food is broken down through a series of chemical reactions that rearrange molecules and release energy. Grades 9-12: The hydrocarbon backbones of sugars produced through photosynthesis are used to make amino acids and other molecules that can be assembled into proteins or DNA. Through cellular respiration, matter and energy flow through different organizational levels of an organism as elements are recombined to form different products and transfer energy. Cellular respiration is a key mechanism to release the energy an organism needs. SOURCE: NGSS Lead States (2013, Appendix E). Copyright 2013 Achieve, Inc. All rights reserved.
crosscutting concept for students at each grade level through 5th grade and in grade bands for middle school and high school.
The progressions in the NGSS are not learning progressions as defined in science education research because they neither articulate the instructional sup- port that would be needed to help students achieve them nor provide a detailed description of students’ developing understanding. (They also do not identify spe- cific assessment targets, as assessment-linked learning progressions do.) However, they are based on the perspective that instruction and assessments must be designed to support and monitor students as they develop increasing sophistica- tion in their ability to use practices, apply crosscutting concepts, and understand core ideas as they progress across the grade levels.
Assessment developers will need to draw on the idea of developing under- standing as they structure tasks for different levels and purposes and build this idea into the scoring rubrics for the tasks. The target knowledge at a given grade level may well involve an incomplete or intermediate understanding of the topic or practice. Targeted intermediate understandings can help students build toward a more scientific understanding of a topic or practice, but they may not them- selves be fully complete or correct. They are acceptable stepping stones on the pathways students travel between naïve conceptions and scientists’ best current understandings.