Planning Effective Science Lessons

High school teachers endeavor to plan engaging and effective science lessons that maximize instructional time. To achieve the most significant gains possible, the focus should be on the most salient aspects of lesson design and sequence of instruction.

To this end, the following four lesson elements underscore a fundamental point about achieving deep and lasting learning—students need to actively “make meaning” to come to understand abstract science concepts.

Step 1: Plan backward

For educational leaders, using Understanding by Design (UbD) procedures helps identify the lesson learning outcomes in terms of what would be acceptable evidence of knowing, and how students would have experiences that allowed them to make more accurate scientific claims. In its essence, UbD is designing a curriculum with the end goal in mind.

From a backward design perspective, identifying the desired evidence-based claims in planning helps focus the teaching on developing students’ conceptual understanding and aligns with the goals of A Framework for K–12 Science Education and Next Generation Science Standards (NGSS). Students can best arrive at an evidence-based claim using the unique combination of disciplinary core ideas, science and engineering practices, and crosscutting concepts. 

Example: Many teachers mix baking soda and vinegar, only to realize that students have little understanding of whether materials and mass change during a chemical reaction—a fundamental idea that’s often misconceived.

Here’s how to remedy that, as this video resource shows. First, place 50 ml of vinegar in an Erlenmeyer flask. Next, place baking soda in a balloon. Carefully stretch the balloon over the mouth of the Erlenmeyer flask, making sure not to mix the baking soda and vinegar. Add a small strip of black electrical tape to seal the balloon to the Erlenmeyer flask with no gaps. Then, place the flask-balloon setup on an electronic balance. Finally, lift the balloon, letting the baking soda come into contact with the vinegar.

When teachers purposefully design lessons using backward design, students can construct evidence-based claims that materials change (gas production as evidenced by the blown-up balloon) and that weight (mass) is conserved. 

Step 2: Engage students’ ideas

Beginning new lessons with students’ ideas and experiences about relevant phenomena makes learning accessible to all students and creates a need-to-know situation. Notice-and-wonder talk and questioning routines provide practical discourse frameworks. Asking, “What do you notice?” invites uninhibited participation (i.e., not tied to fears of assessing ideas) and elicits students’ insights based on their experiences. Questions like “What do you wonder?” are among the highest-yield instructional strategies, since they focus the brain’s attention. Content-based questions can further reveal students’ thinking and experiences and lead to evidence gathering.

Example: Teachers elicit student ideas and experiences before the chemical reaction demonstration and at the onset of the unit. Using a notice-and-wonder routine, teachers ask for observations of the chemicals (i.e., vinegar and baking soda) and curiosity that students might have about what happens when the two are mixed. For students who have seen the chemicals combined in early grades, teachers can ask for a rule for their thinking or evidence from past experiences.

Teachers can simultaneously use content-based formative assessment probes to ask whether students think materials change and if the types and number of atoms are the same before and after a chemical reaction. Beginning new lessons with students’ ideas and experiences activates learning and sets up explorations.  

Step 3: Enhance understanding

Using scientific terminology identified in the NGSS in light of students’ evidence-based claims is a way to entrench ideas and helps develop a conceptual understanding. Readings, discussions, and lectures become potent learning experiences because they connect ideas and students’ frameworks for understanding. 

Example: Teachers can enhance understanding by helping students bridge evidence-based claims from the chemical reaction demonstration to explain what happens on the microscopic level during a chemical reaction. Using computer simulations such as PhET’s balancing chemical equations, students can connect their evidence-based claims about the conservation of mass to types and numbers of atoms being the same before and after a chemical reaction.  

Step 4: Promoting reflection on learning

Evaluation from a learner’s perspective is tied to their sensemaking and a chance to assess how ideas have developed and what strategies lead to more reliable and valid evidence-based claims. John Hattie’s landmark review, which analyzed more than 800 meta-analyses of research, ranked self-reported grades, now termed “student visible learning” (i.e., students thinking about their understanding), as the second most important factor influencing student achievement. 

Example: Throughout the activities in the chemical change lesson, teachers act as guides who ask probing questions inherent in “How have your ideas changed and why?” At the end of the lesson, students revisit their initial answers to the content-based formative assessment probes and provide new scientific claims based on data from their recent firsthand experiences. Probing and reflection questions that ask students to think about their developing understanding help them solve new problems and answer questions for future scientific questions. 

Explore Before Explain

Consider how to develop critical sensemaking elements in an explore-before-explain format. For example, the strategies used to engage students’ ideas should come first in the instructional sequence. The engagement strategies activate student thinking by eliciting prior ideas and experiences and make learning relevant when connected to phenomena in their lives.

Next, students need to have exploration opportunities to construct scientific claims based on evidence (connection to UbD). Then, teachers can use enhancements to introduce ideas (explanations) that are not easily obtained firsthand, as well as scientific terms and concepts that summarize abstract ideas or sophisticated understanding. 

Finally, students need opportunities to think about their learning and reflect on what works to develop a more accurate understanding. The critical point here lies in considering the essential sensemaking features first, and then organizing them into a sequence of exploration before explanation.