19.2 Science Instruction: Inquiry, the 5E Model & Investigations

Overview & Exam Relevance

Competency 005 (Students as Learners and Science Instruction) of the TExES Core Subjects EC-6 Science subject exam covers how students learn science and how teachers plan inquiry-based instruction. Competency 004 (unifying concepts) and Competency 006 (science assessment) have their own sections in this chapter. In Texas public schools, science education has fundamentally shifted away from teacher-centered rote memorization toward student-centered, phenomenological inquiry. The Texas Essential Knowledge and Skills (TEKS) require students to formulate driving questions, design fair-test investigations, identify variables, construct models with explicit awareness of their limitations, and write structured, evidence-based scientific arguments.

On the TExES 391 exam, you must demonstrate a comprehensive grasp of the BSCS 5E Instructional Model, recognize the structural differences among descriptive, correlative, comparative, and experimental investigations, isolate independent and dependent variables, evaluate cross-cutting unifying concepts, and implement formative assessment strategies such as science interactive notebooks and the Claim-Evidence-Reasoning (CER) writing protocol.

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The BSCS 5E Instructional Model

Developed in 1987 by the Biological Sciences Curriculum Study (BSCS) under the leadership of Rodger Bybee, the 5E Instructional Model translates cognitive constructivist theory (Piaget, Vygotsky, Bruner) into an effective, five-phase instructional sequence:

THE 5E INQUIRY INSTRUCTIONAL CYCLE

  1. ENGAGE ──────► Elicit prior knowledge; pique curiosity; uncover misconceptions
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  2. EXPLORE ─────► Hands-on common experience; manipulate materials; test ideas
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  3. EXPLAIN ─────► Students explain findings; teacher introduces formal terms & concepts
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  4. ELABORATE ───► Apply concepts to new, novel situations; extend transfer of learning
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  5. EVALUATE ────► Formative & summative assessment; student self-reflection & rubrics

Detailed Analysis of the 5E Phases

1. Engage: The teacher captures student interest, activates prior knowledge, and establishes a driving question or discrepant event (a counter-intuitive phenomenon that challenges existing mental models). Key Pedagogical Boundary: The teacher does not lecture, define vocabulary, or provide explanations during Engage; the goal is solely to stimulate curiosity and uncover existing student misconceptions.
2. Explore: Students actively manipulate materials, gather observations, record empirical data, and test predictions in cooperative inquiry groups. Students acquire a shared, concrete base of experiential evidence. The teacher acts as an active facilitator and coach—posing open-ended probing questions, redirecting safety concerns, and observing student thinking. Key Pedagogical Boundary: The teacher does not give the answers or tell students what they are "supposed" to see.
3. Explain: First, students verbally communicate their observations, patterns, and developing explanations using the evidence collected during the Explore phase. Second, the teacher introduces formal scientific vocabulary, definitions, and conceptual models that directly connect to the students' concrete observations. Fundamental Rule of Science Pedagogy: Concept and concrete experience BEFORE vocabulary! Introducing vocabulary prematurely in isolation leads to superficial memorization devoid of conceptual understanding.
4. Elaborate: Students apply and extend their newly acquired conceptual understanding and vocabulary to novel, unfamiliar contexts, related real-world phenomena, or engineering design challenges. This phase cements deep relational understanding and facilitates the transfer of learning to new cognitive domains.
5. Evaluate: Assessment is continuous throughout all 5E phases (formative assessment), but the Evaluate phase provides a structured opportunity for both students to self-assess their understanding and the teacher to summatively evaluate student mastery of the TEKS learning objectives using rubrics, performance tasks, or CER writing.

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Teacher versus Student Behaviors in the 5E Instructional Model

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Types of Scientific Investigations in the Texas TEKS

The 2021 science TEKS state that scientific methods of investigation "are descriptive, correlative, comparative, or experimental," and that the method chosen should be appropriate to the grade level and the question being asked:

TEKS INVESTIGATION TYPES
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├── 1. Descriptive Investigations ─► Systematic observation & data collection; NO hypothesis; NO variables manipulated
│                                     (E.g., Observing butterfly life cycle; measuring weather for 30 days)
│
├── 2. Correlative & Comparative ──► HAS a hypothesis predicting a relationship; measure variables; compare results
│                                     (E.g., Comparing water absorption of 3 towel brands; comparing bird beaks)
│
└── 3. Experimental Investigations ──► "Fair test"; manipulates ONE independent variable; measures dependent variable;
                                      holds constants; includes an untreated control group

1. Descriptive Investigations

Involve collecting qualitative and/or quantitative data through systematic observation, measuring, categorizing, and sketching to describe the physical properties or behaviors of a natural system. Descriptive investigations do not involve comparing two distinct groups and do not require a formal hypothesis or manipulated variables.

• Elementary Examples: Observing and drawing the anatomical metamorphosis of mealworms into darkling beetles; mapping the locations of trees on the school playground; recording and graphing the daily ambient temperature and barometric pressure at 12:00 PM for one month.

2. Correlative and Comparative Investigations

The TEKS describe these together: they "have a hypothesis that predicts a relationship and involve collecting data, measuring variables relevant to the hypothesis that are manipulated, and comparing results." A correlative investigation looks for a relationship between two measured variables (for example, whether seedlings that receive more hours of light grow taller). A comparative investigation compares two or more organisms, objects, or conditions. Neither one tests a treatment against a control group.

• Elementary Examples: Comparing the rate of seed germination in potting soil versus sandy soil; comparing the beak shapes of different bird species and inferring their dietary habits; comparing the strength of permanent bar magnets versus disc magnets by counting the number of paper clips each attracts.

3. Experimental Investigations

Involve designing and conducting a rigorous "fair test" to determine cause-and-effect relationships. The TEKS describe experimental investigations as using processes similar to comparative investigations, but testing the hypothesis by comparing a treatment with a control. An experimental investigation systematically manipulates one single factor while keeping all other variables strictly constant, and compares the results against an untreated baseline control group.

• Elementary Examples: Testing how varying the concentration of salt in water affects the freezing point of the solution; determining how changing the angle of an inclined plane affects the distance a toy car rolls.

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Experimental Design Variables & Validity

To conduct a valid fair test, students must master the classification of variables:

EXPERIMENTAL DESIGN VARIABLES
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├── Independent Variable (IV) ──► The ONE factor deliberately manipulated/changed by the investigator
├── Dependent Variable (DV) ────► The responding factor that is measured/observed as data
├── Controlled Variables (CV) ──► All other physical factors held strictly constant across all trials
└── Control Group ──────────────► The unmanipulated baseline group used for comparative comparison

• Independent (Manipulated) Variable: The single variable deliberately altered by the experimenter. Crucial Rule: A valid scientific experiment can have only one independent variable at a time. If multiple variables are manipulated simultaneously, it is impossible to determine which factor caused the observed change in the dependent variable, rendering the investigation scientifically invalid.
• Dependent (Responding) Variable: The factor that changes in response to the manipulation of the independent variable. This is the variable that the investigator measures, observes, and records as empirical data (e.g., plant height in centimeters, time in seconds, mass in grams).
• Controlled Variables (Constants): All other environmental, physical, and procedural variables that are deliberately kept identical across all test groups and experimental trials (e.g., identical container size, same soil type, equal watering volume, identical ambient room temperature, identical light exposure).
• Control Group versus Experimental Group:
  • Experimental Group: The group(s) exposed to the manipulated independent variable (e.g., plants watered with $5\%$, $10\%$, or $15\%$ saline solution).
  • Control Group: The baseline comparison group that is not exposed to the independent variable, serving as the standard of comparison (e.g., plants watered with $0\%$ salt pure distilled water). Without a control group, researchers cannot verify whether the observed effects resulted from the treatment or extraneous background factors.
• Repeated Trials and Sample Size: Elementary students must learn that a single experimental trial is scientifically inadequate. Uncontrolled background fluctuations, measurement error, or atypical biological specimens can create misleading anomalies. Conducting multiple repeated trials (minimum 3 to 5 trials) and calculating the mathematical mean (average) increases experimental reliability.

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Common Science Misconceptions and How to Address Them

Effective conceptual change begins by eliciting students' ideas (for example, with a prediction or a formative probe). The teacher then creates dissatisfaction with the misconception through a discrepant event and offers a scientific explanation that is intelligible, plausible, and fruitful.

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Questioning, Sequencing, and Meeting All Learners' Needs

• Questioning for higher-level thinking: Move from recall ("What happened?") to analysis ("Why do you think that happened?"), evaluation ("Which design worked better, and what is your evidence?"), and creation ("How could we change the design?"). Provide wait time of at least three seconds after a question.
• Sequencing: Build from concrete experiences to representations to abstract explanations, and connect each lesson to prior knowledge. For example, students explore magnets with real objects before drawing field diagrams.
• Developmental characteristics: Young children learn best through hands-on exploration and observation. Older elementary students can control variables, use measurement tools precisely, and reason from data.
• English learners: Use realia, visuals, word walls, sentence stems ("I observed ___, so I think ___"), cooperative groups, and cognates (evaporation and evaporación).
• Students with disabilities: Provide adaptive tools (large-print rulers, talking thermometers, tactile models), extra time, and assigned roles in group work.
• Daily-life connections: Investigate questions from students' lives, such as which paper towel is the best buy or why bread molds, to show how science helps people make informed decisions.
• Engineering practices: The 2021 TEKS add engineering. Students define a problem, design and build a solution, test it, and improve it, for example by designing a shelter that keeps an ice cube from melting.

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Classroom Scenario Application

Classroom Context: Mr. Cooper's 5th-grade class is conducting an experimental investigation to determine how different surface textures affect the friction acting on a wooden block. The driving question is: "How does the surface texture of a ramp affect the distance a block slides?"

Investigation Setup:

• Independent Variable: The surface material glued to the ramp (smooth bare wood, wax paper, coarse sandpaper, and terrycloth felt).
• Dependent Variable: The distance the wooden block slides across the floor (measured in centimeters using a metric meter stick).
• Controlled Variables (Constants): Identical wooden block, same ramp incline height (20 cm), releasing the block from the same starting mark without pushing, and identical smooth linoleum floor surface.
• Control Group: The smooth, untreated bare wood ramp.

Student Experimental Data (Average across 5 trials):

• Wax paper: $85\text{ cm}$
• Smooth bare wood (control): $62\text{ cm}$
• Terrycloth felt: $34\text{ cm}$
• Coarse sandpaper: $18\text{ cm}$

Exemplary Student CER Written Argument:

• Claim: "Covering the ramp with rougher surface textures causes the wooden block to travel a shorter distance."
• Evidence: "When the ramp was covered in coarse sandpaper, the block traveled an average of only 18 cm. On the untreated smooth wood, the block traveled 62 cm, and on smooth wax paper, it traveled 85 cm. The sandpaper reduced the sliding distance by 44 cm compared to the bare wood."
• Reasoning: "Friction is a contact force that opposes the motion of sliding objects. Coarse surfaces like sandpaper have large microscopic ridges and bumps that catch against the wooden block, generating higher frictional resistance that converts the block's kinetic energy into thermal energy more rapidly. Smoother surfaces like wax paper produce less friction, allowing the block to retain more kinetic energy and travel farther."

Assessment Scoring (Rubric Evaluation): Mr. Cooper evaluates the student's response using an analytic CER rubric, awarding maximum points because the claim directly answers the driving question, the evidence cites specific quantitative comparative data with metric units ($cm$), and the reasoning correctly applies the physics concept of friction as an opposing contact force governing energy transformation.