Teaching Science: Argument and Evidence

This tweet showed up in my Twitterfeed today...

A science classroom should be filled with the noise of students collecting evidence and arguing.

— Jennifer Weibert (@ngssfresno) July 9, 2018

I love this so much, and it sums up so much of the philosophy for teaching science that I tried to embody as a middle school science teacher, and now as I teach future science teachers as well.

Truth and Facts

In my Science Methods class today, we spent much of our time discussing the difference between "facts" and "truth." This feels so germane to so many issues in culture today that it was really something I wanted to talk about--and, serendipitously, it was on the syllabus for today anyway.

I'm using a text by John Mays entitled Teaching Science so that Students Learn Science, and chapter 2 of the book is entitled "Truth and Facts." In this chapter, Mays is really talking about science as a way of knowing about the world. And there are definitely different ways of knowing! Mays emphasizes that science is about developing an empirical understanding of the world--the facts, we might say.

Here are his working definitions for "truth" and "facts": (from p. 17 of the book)

Truth: A proposition that is true for all times, all places, and all people. Truths never change. We know truths by revelation or first hand testimony.

Fact: A proposition that is supported by substantial experimental or observational evidence (data), and which is correct as far as we know. Facts can change as new data and information become known. We know facts by observation and experiment, or by making inferences from our observations and experimental results.

How does that sound to you? Are these helpful definitions?

The Importance of Modeling

Some days, I know that teaching is for me. And I had one of those days recently.

In a recent post, I was wondering about the nature of teaching, and whether teachers are actually "teaching" if their students aren't learning. I sometimes doubt my own efficacy as a professor--am I really cut out for this work? What really qualifies me to teach someone else how to teach? Am I really that effective at this business?

And then I have a moment where I see things coming together...

I have been visiting student teachers throughout this semester, and I have been so proud of my students--seeing them putting into practice the things they have learned throughout their work in our teacher preparation program is gratifying to say the least!

But recently I had an almost surreal experience on a visit one of my student teachers. She was particularly eager to have me visit for this lesson--it was a science lesson. I teach the science methods course for elementary and middle school majors, so she was right: I am always excited to see student teachers leading a science learning opportunity.

The lesson? Part of a unit she was teaching about states of matter. The third graders had already learned about solids, liquids, and gases, and how it's possible to change from one state of matter to another, and what makes these different states function as they do. And today's lesson was a chance for them to check and extend their understanding.

My student teacher began by asking questions of the students, helping them review the characteristics of the different states of matter. I was so proud already at this introduction; in science methods I had emphasized the importance of asking a variety of different kinds of questions--some basic, recall questions, but also higher-order thinking questions--and here she was, using all sorts of questions to engage her students and help conduct them in to the lesson of the day.

And then: a Magic Question...

There is DNA in Your Smoothie!

DNA is an actual real thing. DNA is the "blueprint" for how to build a particular organism. Human beings, lobsters, oak trees, bacteria, strawberries, platypus (platypi? playtpuses?)...all living things are made of cells, and all of them have DNA in their cells that contain the instructions for how to build the structures of that particular organism.

Most of you won't be shocked to hear this, I know.

But have you ever wished you could see DNA? How do we really know it's a thing, if it's so small that we can't really see it?

This is a real problem for science teachers. We often are working with things that are too small, or too big, or too dangerous to show students directly. So we create models, or play videos, or show pictures...which are all good options, of course.

Take DNA as an example. When I used to teach students about DNA, I often showed them pictures of the double-helix structure in their textbook. We would view video clips of how DNA can make copies of itself using the microscopic machinery of living cells. I would have groups of students create construction paper models of the ladder-like structure of DNA.

But wouldn't it be nice to show students DNA first hand, if possible?

Will It Float?

In Science Methods this week we have been learning more about what inquiry-infused science learning looks like. I really like the "5 E's" learning cycle for managing an inquiry-infused science class, and I've been recommending this to my students. (This model was developed by Rodger Bybee and colleagues in the Biological Sciences Curriculum Study; you can read their executive summary if you want more details...)

The 5 E's are a way of organizing learning activities for a student-centered, constructivist approach to science learning. The 5 E's are five "movements" in an inquiry learning cycle that describe what the teacher and students are doing. In a nutshell:

Engage - The teacher provides some sort of hook (a discrepant event, a connection to students' world, etc.) to foster curiosity and set the stage. This provides motivation and a need-to-know to set up the inquiry.

Explore - The students conduct a first-hand investigation to develop their thinking about the science concept to be learned. This movement often exposes students misconceptions about science concepts, and also gives them concrete experiences that can provide the basis of new learning.

Explain - In this movement, both the students and the teacher have the opportunity to do some explaining. The students explain their current thinking, based on their experiences in the Explore movement. The teacher has the opportunity to probe their thinking, ask questions, help them voice their ideas...and provide direct instruction to help students think more scientifically about the concepts being considered. This is the movement where teachers help mediate students' understanding of the content.

Elaborate - The students then have the opportunity to continue working with these new ideas, extending their thinking through another learning activity. This might be another hands-on investigation, further research, or some sort of creative response that incorporates the science concepts. They key is that students continue to develop their thinking about the science content, elaborating on what they have previously learned in the Explore and Explain movements.

Evaluate - Finally, students and teacher work together to find out what the students are now thinking about the concepts. Assessment of learning happens here, with the students (hopefully) able to say, "I used to think...but now I think..."

We had previously learned about the 5 E's learning cycle, but I wanted my students to experience a learning cycle firsthand. So, we took a couple class meetings to learn about floating and sinking, a common elementary science topic. Here's what we did:

"Doing Science" with Fortune Fish

I love the variety of courses I get to teach for pre-service teachers. The one I've been teaching the longest is "Teaching Science PreK-Middle School." I began adjuncting this course in 2007, and it has slowly evolved over time to the current state, after 15 or so iterations.

One of the key themes that has not changed, however, is that I have my science methods students "do science" on a weekly basis. That is, we aren't just learning about science; we are actively investigating, observing, inferring, experimenting, and communicating what we discover. I want them to experience learning science this way in the hope that they will carry this approach to teaching science into their own classrooms down the road.

So, when we began the new semester in science methods yesterday, their first assignment is an investigation...

I handed out a little plastic sleeve to each student:

What's in the package?