Constructing explanations
and designing solutions

Strategies to promote Belonging with Constructing an Explanation:

To feel belonging, students must feel comfortable with each other and know that when they share their explanation that they won’t be met with judgment. This culture must be built intentionally. The instructional strategies that foster this culture are ones that emphasize safe spaces for students to share out their explanations and solutions, give feedback to peers, and engage in scientific argumentation about the science. In addition, students should feel as though they are a part of a community of scientists and engineers all trying to tackle the same problem. Some ways to do this are to use protocols in which students are assigned roles, encouraging students to use their every day or home language in initial explanations, provide sentence starters for when giving feedback, and allow for multiple ways of sharing out. To learn more visit here.

Strategies to promote Confidence in Constructing an Explanation:

Building confidence means lots of practice in the skills that are needed to construct an explanation. These skills include making a claim, identifying and sharing evidence, and using reasoning to support the claim. These skills are used in all disciplines but are done in a unique way in science. Teachers can structure this by having students think things out in a group before constructing their own explanation. Students should also examine and evaluate samples (from diverse voices and on diverse topics) of explanations to better understand the different elements. Tools should also be provided to scaffold any language barrier such as vocabulary lists, sentence stems, technology services, etc.To learn more visit here.

Learning Orientation for promoting Constructing an Explanation:

Having a learning orientation for constructing an explanation means that students understand that there is no single right way to explain a phenomenon. The purpose of this practice is for students to be able to think deeply and meaningfully about the phenomena instead of just seeing an explanation as a thing to check off their list as a classroom task. Some ways to do this are to use a jigsaw protocol, gallery walks, “lab meetings” and other ways to share out different ways to explain. Students should also study examples where multiple explanations may apply to one phenomena. Make sure, as always, to provide plenty of structure and scaffolding like graphic organizers, sentence stems, and vocabulary practice. To learn more visit here.

Strategies to promote Autonomy in Constructing an Explanation:

Students should practice independently answering open ended questions using the model of claim, evidence and reasoning. In order for students to get better at this, students should examine and reflect on their explanations using a rubric. In addition, organizers that chunk and structure each piece could be helpful for students to work on independently. To learn more visit here.

Strategies to promote Relevance in Construction an Explanation:

Because construction of explanations is a practice that can be used in any context, this is a great opportunity for students to be able to pursue questions and phenomena that they are curious about. Students will be more likely to properly check the evidence and make a strong claim. In general, teachers should share explanations that connect to students’ lives such as an explanation for spread of local pathogens, or the effect of invasive species on local ecosystems. To learn more visit here.

Standard Name: HS-ETS1-3 Engineering Design

Standard: Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.

Observable Features of Student Performance by the end of the Course: 

1. Evaluating potential solutions

• In their evaluation of a complex real-world problem, students: 

  • • Generate a list of three or more realistic criteria and two or more constraints, including such relevant factors as cost, safety, reliability, and aesthetics that specifies an acceptable solution to a complex real-world problem; 

    • Assign priorities for each criterion and constraint that allows for a logical and systematic evaluation of alternative solution proposals; 

    • Analyze (quantitatively where appropriate) and describe* the strengths and weaknesses of the solution with respect to each criterion and constraint, as well as social and cultural acceptability and environmental impacts;

    • Describe* possible barriers to implementing each solution, such as cultural, economic, or other sources of resistance to potential solutions; and 

    • Provide an evidence-based decision of which solution is optimum, based on prioritized criteria, analysis of the strengths and weaknesses (costs and benefits) of each solution, and barriers to be overcome.

2. Refining and/or optimizing the design solution

• In their evaluation, students describe* which parts of the complex real-world problem may remain even if the proposed solution is implemented.

Standard Name: HS-ESS3-4 Earth and Human Activity

Standard: Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.

Observable Features of Student Performance by the end of the Course: 

1. Using scientific knowledge to generate the design solution

• Students use scientific information to generate a number of possible refinements to a given technological solution. Students: 

  • • Describe* the system being impacted and how the human activity is affecting that system; 

    • Identify the scientific knowledge and reasoning on which the solution is based; 

    • Describe* how the technological solution functions and may be stabilizing or destabilizing the natural system;

    • Refine a given technological solution that reduces human impacts on natural systems; and

    • Describe* that the solution being refined comes from scientists and engineers in the real world who develop technologies to solve problems of environmental degradation.

2. Describing criteria and constraints, including quantification when appropriate

• Students describe* and quantify (when appropriate):

  • • Criteria and constraints for the solution to the problem; and 

    • The tradeoffs in the solution, considering priorities and other kinds of research-driven tradeoffs in explaining why this particular solution is or is not needed.

3. Evaluating potential refinements

• In their evaluation, students describe* how the refinement will improve the solution to increase benefits and/or decrease costs or risks to people and the environment. 

• Students evaluate the proposed refinements for: 

  • • Their effects on the overall stability of and changes in natural systems; and

    • Cost, safety, aesthetics, and reliability, as well as cultural and environmental impacts.

Standard Name: HS-ESS1-2 Earth's Place in the Universe

Standard: Construct an explanation of the Big Bang theory based on astronomical evidence of light spectra, motion of distant galaxies, and composition of matter in the universe.

Observable Features of Student Performance by the end of the Course: 

1. Articulating the explanation of phenomena

• • Students construct an explanation that includes a description* of how astronomical evidence from numerous sources is used collectively to support the Big Bang theory, which states that the universe is expanding and that thus it was hotter and denser in the past, and that the entire visible universe emerged from a very tiny region and expanded.

2. Evidence

• • Students identify and describe* the evidence to construct the explanation, including:

    • • The composition (hydrogen, helium and heavier elements) of stars; 

      • The hydrogen-helium ratio of stars and interstellar gases; 

      • The redshift of the majority of galaxies and the redshift vs. distance relationship; and

      • The existence of cosmic background radiation.

  • Students use a variety of valid and reliable sources for the evidence, which may include students’ own investigations, theories, simulations, and peer review.

  • Students describe* the source of the evidence and the technology used to obtain that evidence.

3. Reasoning

• • Students use reasoning to connect evidence, along with the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future, to construct the explanation for the early universe (the Big Bang theory). Students describe* the following chain of reasoning for their explanation:

    • Redshifts indicate that an object is moving away from the observer, thus the observed redshift for most galaxies and the redshift vs. distance relationship is evidence that the universe is expanding.

  • The observed background cosmic radiation and the ratio of hydrogen to helium have been shown to be consistent with a universe that was very dense and hot a long time ago and that evolved through different stages as it expanded and cooled (e.g., the formation of nuclei from colliding protons and neutrons predicts the hydrogen-helium ratio [numbers not expected from students], later formation of atoms from nuclei plus electrons, background radiation was a relic from that time).

  • An expanding universe must have been smaller in the past and can be extrapolated back in time to a tiny size from which it expanded.

Standard Name: HS-LS4-2 Biological Evolution: Unity and Diversity

Standard: Construct an explanation based on evidence that the process of evolution primarily results from four factors: (1) the potential for a species to increase in number, (2) the heritable genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for limited resources, and (4) the proliferation of those organisms that are better able to survive and reproduce in the environment.

Observable Features of Student Performance by the end of the Course: 

1. Articulating the explanation of phenomena

• Students construct an explanation that includes a description* that evolution is caused primarily by one or more of the four factors: (1) the potential for a species to increase in number, (2) the heritable genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for limited resources, and (4) the proliferation of those organisms that are better able to survive and reproduce in the environment.

2. Evidence

• Students identify and describe* evidence to construct their explanation, including that: 

  • • As a species grows in number, competition for limited resources can arise.

    • Individuals in a species have genetic variation (through mutations and sexual reproduction) that is passed on to their offspring.

    • Individuals can have specific traits that give them a competitive advantage relative to other individuals in the species.

• Students use a variety of valid and reliable sources for the evidence (e.g., data from investigations, theories, simulations, peer review). 

3. Reasoning

• Students use reasoning to connect the evidence, along with the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future, to construct the explanation. Students describe* the following chain of reasoning for their explanation:

  • • Genetic variation can lead to variation of expressed traits in individuals in a population. 

    • Individuals with traits that give competitive advantages can survive and reproduce at higher rates than individuals without the traits because of the competition for limited resources.

    • Individuals that survive and reproduce at a higher rate will provide their specific genetic variations to a greater proportion of individuals in the next generation. 

    • Over many generations, groups of individuals with particular traits that enable them to survive and reproduce in distinct environments using distinct resources can evolve into a different species.

• Students use the evidence to describe* the following in their explanation:

  • • The difference between natural selection and biological evolution (natural selection is a process, and biological evolution can result from that process); and 

    • The cause and effect relationship between genetic variation, the selection of traits that provide comparative advantages, and the evolution of populations that all express the trait.

Standard Name: HS-LS2-3 Ecosystems: Interactions, Energy, and Dynamics

Standard: Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions.

Observable Features of Student Performance by the end of the Course: 

1. Articulating the explanation of phenomena

• Students construct an explanation that includes that: 

  • • Energy from photosynthesis and respiration drives the cycling of matter and flow of energy under aerobic or anaerobic conditions within an ecosystem. 

    • Anaerobic respiration occurs primarily in conditions where oxygen is not available.

2. Evidence

• Students identify and describe* the evidence to construct the explanation, including:

  • • All organisms take in matter and rearrange the atoms in chemical reactions.

    • Photosynthesis captures energy in sunlight to create chemical products that can be used as food in cellular respiration.

    • Cellular respiration is the process by which the matter in food (sugars, fats) reacts chemically with other compounds, rearranging the matter to release energy that is used by the cell for essential life processes.

• Students use a variety of valid and reliable sources for the evidence, which may include theories, simulations, peer review, and students’ own investigations.

3. Reasoning 

• Students use reasoning to connect evidence, along with the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future, to construct their explanation. Students describe* the following chain of reasoning used to construct their explanation: 

  • • Energy inputs to cells occur either by photosynthesis or by taking in food.

    • Since all cells engage in cellular respiration, they must all produce products of respiration. 

    • The flow of matter into and out of cells must therefore be driven by the energy captured by photosynthesis or obtained by taking in food and released by respiration. 

    • The flow of matter and energy must occur whether respiration is aerobic or anaerobic.

4. Revising the explanation

• Given new data or information, students revise their explanation and justify the revision (e.g., recent discoveries of life surrounding deep sea ocean vents have shown that photosynthesis is not the only driver for cycling matter and energy in ecosystems)

Standard Name: HS-LS1-1 From Molecules to Organisms: Structures and Processes

Standard: Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

Observable Features of Student Performance by the end of the Course: 

1. Articulating the explanation of phenomena 

• Students construct an explanation that includes the idea that regions of DNA called genes determine the structure of proteins, which carry out the essential functions of life through systems of specialized cells.

2. Evidence

• Students identify and describe* the evidence to construct their explanation, including that: 

  • • All cells contain DNA; 

    • DNA contains regions that are called genes; 

    • The sequence of genes contains instructions that code for proteins; and 

    • Groups of specialized cells (tissues) use proteins to carry out functions that are essential to the organism

• Students use a variety of valid and reliable sources for the evidence (e.g., theories, simulations, peer review, students’ own investigations). 

3. Reasoning

• Students use reasoning to connect evidence, along with the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future, to construct the explanation. Students describe* the following chain of reasoning in their explanation:

  • • Because all cells contain DNA, all cells contain genes that can code for the formation of proteins. 

    • Body tissues are systems of specialized cells with similar structures and functions, each of whose functions are mainly carried out by the proteins they produce. 

    • Proper function of many proteins is necessary for the proper functioning of the cells.

    • Gene sequence affects protein function, which in turn affects the function of body tissues.

Standard Name: HS-PS1-5 Matter and its Interactions

Standard: Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.

Observable Features of Student Performance by the end of the Course: 

1. Articulating the explanation of phenomena

• • Students construct an explanation that includes the idea that as the kinetic energy of colliding particles increases and the number of collisions increases, the reaction rate increases. 

2. Evidence

• • Students identify and describe* evidence to construct the explanation, including:

    • • Evidence (e.g., from a table of data) of a pattern that increases in concentration (e.g., a change in one concentration while the other concentration is held constant) increase the reaction rate, and vice versa; and

      • Evidence of a pattern that increases in temperature usually increase the reaction rate, and vice versa.

3. Reasoning

• • Students use and describe* the following chain of reasoning that integrates evidence, facts, and scientific principles to construct the explanation: 

    • • Molecules that collide can break bonds and form new bonds, producing new molecules. 

      • The probability of bonds breaking in the collision depends on the kinetic energy of the collision being sufficient to break the bond, since bond breaking requires energy. 

      • Since temperature is a measure of average kinetic energy, a higher temperature means that molecular collisions will, on average, be more likely to break bonds and form new bonds.

      • At a fixed concentration, molecules that are moving faster also collide more frequently, so molecules with higher kinetic energy are likely to collide more often.

      • A high concentration means that there are more molecules in a given volume and thus more particle collisions per unit of time at the same temperature.