Future Scientist? Not Your Kid

It's the Books, Y'all

You may not realize this, but the science books and programs used in public schools (and now in homeschools) are developed based on strict learning progressions for topics like atomic-molecular theory. Learning progressions (LPs) are essentially maps designed to outline the steps a student should take to learn and understand increasingly complex information.

However, the primary purpose of LPs was for assessment—to answer the question "What do we test?" Somewhere along the way, these progressions morphed into the sole pathway for learning a given topic. They became the gatekeepers for what topics are included in NGSS (Next Generation Science Standards) and the criteria for determining which curricular materials or programs are permitted in classrooms.

The Problem with Learning Progressions

Learning progressions look impressive on paper, but they don't work in practice. We know this because despite their influence on classroom instruction, curricular materials, and online instruction for decades, we've seen a steady decline in students' abilities to transition from high school to college-level science.

Not only do these LPs fail to work, but the research supporting them is weak at best, often missing, and inaccurately presented as "evidence" in almost all publications supporting how and what kids can learn, particularly about atoms and molecules.

Curious to know more? Keep reading.

Challenging the "Research"

Learning Progressions (LPs) gained traction in the early 2000s. Discussions about science literacy benchmarks began in the late '80s and '90s, but the LP concept didn't fully form until the mid-2000s. A proposed LP for the theory of evolution and another for atomic-molecular theory by Smith et. al. (2006) are frequently cited today as "evidence-based" foundations that shape standards, curricular materials, and assessments.

So, what is the evidence? Does the research actually support the notion that LPs and coherent curricular materials are reliable pathways to deeper student understanding?

Ready for a deeper dive? Let's get into the weeds.

The LP for Atomic-Molecular Theory

The LP for atomic-molecular theory rests on two key assumptions:

1. Students cannot learn about atoms and molecules before middle or high school due to cognitive developmental stages.
2. Learning about the properties of matter is a necessary precursor to understanding atomic-molecular theory (AMT).

The first assumption stems from the work of Jean Piaget, a Swiss psychologist who, after studying his own children in the 1920s, posited that cognitive development precedes learning. In other words, a student must pass through lower cognitive stages before acquiring material from higher stages. The Smith et. al. (2006) paper, which forms the basis for the LP for AMT, cites Piaget's work as "evidence" and justifies focusing on the properties of matter in elementary grades. According to Piaget, the concept of atoms is too abstract for students younger than 11, so elementary-aged students should focus on the properties of matter.

There are no issues with the Smith et al. (2006) paper itself. They were asked by the National Research Council (NRC) to develop a paper for assessment in 2004, leading to the 2006 publication. This is fine. They also acknowledge that their LP is based on "conjecture," that other LPs are possible, and that most students don't complete the progression to learn about atoms and molecules.

The problem is that this paper, intended for assessment and "based on conjecture," is cited as "evidence" for why elementary students can't and shouldn't learn anything about atoms or molecules beyond the notion that they are "particles too tiny to be seen."

The Real Issue

The second assumption, that learning about the properties of matter is a necessary precursor to understanding atomic-molecular theory, has never been tested, validated, or proven in any meaningful way.

As a former academic chemist, I can't recall spending much time on the properties of matter in my college courses. Yes, it's mentioned, but in most freshman chemistry textbooks, it's a subsection of the first or second chapter. The rest of the book focuses on atoms, molecules, molecular bonding, thermodynamics, electrochemistry, and nuclear chemistry. My classes were heavy on math and had little to do with the observable properties of matter.

So, is there any research supporting the idea that students need to learn about the properties of matter before they can understand atoms and molecules? The 2023 Handbook of Research on Science Education Vol III, p.137 cites an article by Wiser and Smith (2013) that says correlational studies support the link between macroscopic understandings of matter and understanding AMT as an explanatory model. However, the cited study by Snir, Smith, and Raz (2003) had a small sample size of 28 students and no statistical evaluation, showing inconclusive results.

Understanding Molecular Bonding Saves Lives

Rush Stockton made a critical decision to choose carbon fiber over titanium solely based on its buoyancy—a property of matter. While we can't say for certain how well Stockton grasped the difference between covalent and metallic bonds, he clearly ignored a fundamental fact of molecular bonding: covalent bonds in carbon fiber do not rearrange to relieve microscopic stressors caused by heat or pressure, whereas metallic bonds in titanium do. No one on board this submersible seems to have connected the properties of matter to atomic-molecular theory.

Why Does It Matter?

The consequence of withholding knowledge about atoms and molecules from elementary students can be profound. Waiting until middle school or high school to introduce atomic-molecular theory limits early cognitive development and understanding of fundamental scientific concepts. By delaying this learning, we miss the opportunity to build a strong foundation, potentially leading to critical oversights and misunderstandings, much like Stockton's.

Atomic-molecular theory should start with atoms and molecules. Early education in atomic and molecular theory could not only foster greater scientific literacy but also prepare students to make well-informed decisions in their future careers, ultimately saving lives and advancing technological innovation.

It's time for a change.

After decades of inadequate and misleading science books and programs resulting in fewer and fewer students who can't make it into the careers of their dreams, aren't we ready for change? The choice is clear: Change or more of the same?” 

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References

Smith, C. L., Wiser, M., Anderson, C. W., & Krajcik, J. (2006). Focus article: Implications of research on Children’s learning for standards and assessment: A proposed learning progression for matter and the atomic-molecular theory. Measurement: Interdisciplinary Research & Perspective, 4(1–2), 1–98. https://doi.org/10.1080/15366367.2006.9678570

Snir, J., Smith, C., &
Raz, G. (2003). Linking phenomena with competing underlying models: A software
tool for
introducing students to the particulate model of matter. Science Education, 87,
794–830.

Wiser, M., & Smith, C. (2013). Learning and teaching about matter in the middle-school years: How can the atomic–molecular theory be meaningfully introduced? International Handbook of Research on Conceptual Change, 189–206. https://doi.org/10.4324/9780203154472-17