What should a kid get out of high school science?

Some friends asked me this question recently, and I gave a bad answer. In my bad answer I said something like “They should know some things. Some big ideas.” And I listed a few that came to mind, like conservation of energy. I don’t think there’s anything too terribly wrong with that idea, I just don’t think it’s enough. Students should know some “big ideas”, but also they should be able to do some science. This post is an attempt to give a better answer.

First, about the big ideas kids (and everybody) should know.  I’ve always liked the book Science Matters: Achieving Scientific Literacy by Hazen and Trefil. It’s still in print,25 years after I first read it, and still relevant.  It’s written for everybody. It’s engaging, and the prose has a sense of style. And it relays a good summary of the basic science concepts in every discipline; the big ideas a person should understand after a basic course in science  like astronomy, biology, chemistry, or physics. So read the book, or this one you can download for free, if you are really interested.

That said, here are a few big ideas I hope students leave school conversant in:

  1. atoms , since somebody else said it better, I quote: “all things are made of atoms—little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another.” R.P. Feynman Lectures on Physics
  2. some things we can calculate (“quantities”) are conserved. in a closed system, the amount never changes: matter, energy, momentum, angular momentum, charge
  3. the universe, galaxies, solar systems, stars, planets are continuously changing in ways that are both understood and mysterious
  4. the earth is the only living system known, and it is a system of interconnected parts, both living and non-living
  5. organisms evolve, and their evolution can be understood both through fossils and observing living things; there is a common chemical basis for all life
  6. at different scales (of space, time, and energy), different methods of investigation and description are needed
  7. scientific understanding is constantly changing. a community of scientists works together to create the current best understanding. there are still many unanswered questions and huge gaps in our understanding

Now, about the science students should do (influenced by/condensed from modeling instruction and by the College Board’s Advanced Placement Science Practices):

Scientists make observations. Observations in science are usually measurements. No measurement is perfect; there is a limit to what can be known by measurement. The limits keep changing as technology improves, but there will always be a limit. Students should be able to make accurate measurements with classroom equipment, and be able to describe the limits of those measurements. Experiments are situations we create in order to make very specific observations.

Students should be able to create an experiment, or critique the flaws in somebody else’s experiment. They should understand the limitations of an experiment and also recognize when an experiment could be performed to find an answer, or at least the beginnings of an answer to a scientific question.

Observations/measurements are described by patterns. This is one of the deepest big ideas in science: there are recognizable patterns in nature. Some patterns are easier to observe, some more difficult. Patterns can be described by mathematics. When we know enough about a pattern, we use math, words, graphs to describe a conceptual model that encapsulates what we know about the pattern. Students should be able to describe the patterns in measurements using mathematics. They should be able to generalize these descriptions to describe conceptual models about nature.

Scientists make claims that are evaluated on the basis of evidence. Students should be able to make and evaluate scientific claims.

What’s the balance here between learning ideas and doing science? Ideally, students would learn science by doing science, as in methods like Modeling instruction, Process-Oriented Guided Inquiry Learning, Problem-Based Learning, and other inquiry instruction.

This is a very idealistic discussion. Being science literate depends on having a good understanding of these concepts and practices. Most students, those who just go through the motions in school as we know it, are not going to have that understanding. This discussion also leaves out engineering practices and applications, something important in the Next Generation Science Standards (and likely the to-be-released Arkansas High School Frameworks). So, I think this is a better answer, but not THE answer. Comments?

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Good Intentions

The Board of Education of the state of Arkansas has recently released the descriptions of the new Next Generation Science Standards-inspired courses for high school, debuting 2017-2018:  Proposed High School Science Courses.

There are a lot of things to like in this plan. It is ambitious. It aims for a future where all students have some measure of competency in the ideas and practices of science and engineering. It incorporates earth and space science objectives at all levels of 6-12 science. And the state will demand that all students take three years of high school science. Under the old “Smart Core” plan, only students who wanted to qualify for the Arkansas Academic Challenge Scholarship had to take three years of science. The NGSS-inspired revised Arkansas frameworks are likely to be much better than the old frameworks, which were heavy on facts to memorize and equations to manipulate, but light on understanding.

There are some significant challenges to this plan. The biggest one might be that every student is going to take “Principles of Chemistry and Physics.” There may be enough physics-certified teachers in Arkansas to accomplish this plan, but I really doubt that there are enough physics-savvy teachers in the state to carry it out. Physics certification is a low bar. Basically, anyone with a degree (a degree, not a degree in science) who can pass the Praxis in a subject can be certified to teach that subject. The Praxis, in my opinion, is not a test that demands deep understanding of the subject. Most teachers in this situation (forced to teach physics without the expertise, desire, or tools) will fall back on memorization, equation manipulation, or reduce the physics content in favor of the chemistry content.

Another challenge is the culture and climate around public education in the state of Arkansas. Most parents and students like the idea of students being college-ready, but their vision of college-ready does not include pushing students to understand and practice science. If students are asked to think, question, and understand, many parents and students will push back, and the pressure on teachers to revert to the status quo will be extreme.

Changing the entire system of Arkansas science education at once is a huge challenge. It’s going to require the cooperation and understanding of parents, students, teachers, and administrators. I hope there is an exceptional plan in place for educating everyone involved about the new frameworks. And more importantly, a plan providing professional development for all those who will be forced to teach science areas they are uncomfortable with. Unfortunately, some of my fellow teachers treat professional development as just a hoop to jump through, and choose to gain nothing from it. A two-day workshop is not going to be enough to change their minds about the importance of teaching for student understanding, or to provide an understanding of physics concepts.

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Using Tasks Inspired by Physics Education Research

Below are my thoughts on the Tasks Inspired by Physics Education Research (TIPERS).
These are really excellent tools to promote discussion in your physics class, no matter what the level. I strongly recommend buying one or more of these books. By the way, a lot of hard work by physics teachers like yourselves went into these books, and the authors are not making large amounts of money from them. So, if you meet one of the authors, thank them.

In my opinion, if you are only going to buy one of these books, you should get the “Sensemaking Tasks” book (the one with the blue cover). It has the widest range of different types of tasks and content. The Electricity and Magnetism Tasks book seems to be intended for Calculus-based physics courses like AP Physics C, Electricity and Magnetism. Many of the tasks in this book are very challenging. The Ranking Tasks book and the Newtonian TIPERS are both very good and very useful for both Physics C and Physics 1-2 (Newtonian TIPERS less so for Physics 2, of course).

TIPERS present a scenario that may be a familiar lab or “real-life” experience, often with a diagram and several different but similar alternative scenarios. Students are asked to do various things, rank the scenarios, find contradictions in student “analysis” of the scenarios, or simply explain something using physics. Although numbers may be given for physical quantities, TIPERS are generally not answered through calculation, and rarely are enough numbers given that students could plug numbers into an equation to find answers. Some TIPERS may be answered with little to no mathematic reasoning, and are more conceptual than mathematical. Others are very much easier if you reason proportionally using the equation, even though you don’t have complete information on all of the variables given in the task.

I generally use TIPERs with a conceptual basis early in a unit. I pass the task out, ask student to complete it silently and individually. This usually takes 5-10 minutes. After everyone has completed the task, including explaining their reasoning (a particularly important step), students discuss with their group or neighbors for an additional 5-10 minutes. When the groups have had a chance to reach consensus, I ask one or more groups to present their answers to the class, and the whole class tries to reach a consensus. I have been walking around talking to the groups, so I can choose to pick a group with the correct answer, or to pick a group with flawed reasoning but an interesting explanation for their reasoning.

I usually follow the same procedure with the more mathematical TIPERS, except that I wait until after students understand the equations to use them. It is often possible to answer these conceptually, using proportional reasoning but not an equation, but this is often a bit tortuous. It may take a little experience before you get a feel for the best time to use a particular TIPER, but once you discover that moment, you will probably want to use it every year in the same way. I usually only give one or two TIPERs per class meeting, and I don’t use them every class meeting. At this rate, students seem to enjoy them, and the discussions have been very productive. I insist on students writing complete answers, and sometimes take up the papers for a “participation” grade. No writing, no grade. I think this type of practice is especially useful for AP Physics 1 and 2, with the increased writing demands of their exams.

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Standards-Based Quizzing

This year in AP Physics 1 I’ve made a step towards Standards-Based Grading. I know I am several years behind the curve on this, but I am glad that I finally decided to make it happen. The slower pace of AP Physics 1 has made a big difference; I don’t see how I could be doing this in AP Physics B.

Over the summer, Tiffany Taylor of Rogers Heritage High and I worked to institute SBG, based largely on Frank Noschese’s excellent blog post, Keep It Simple Standards-Based Grading. I started with standards that other people (Frank Noschese, Mark Hammond on an older website) had published on their websites, based on the 9 modeling units that are presented at most modeling physics workshops.

Here’s a summary of differences between this year and last year:

Last year’s quiz questions – tailored after an AP exam, with difficult questions mixing topics. Usually two or three per unit. Quizzes were 20% of the grade. For most students quizzes lowered your grade and it was difficult to study for them or do consistently well.

This year’s quiz questions– frequent and straightforward, with a standard associated with each question. Each standard graded on a simple scale (2=I think you showed me that you understand the standard; 1=You seem to understand part of the standard, but not all of it; 0=I see no evidence that you understand the standard, or I see some evidence that you understand part of the standard but other evidence that you misunderstand part of the standard). Students can redo quiz questions if they have not passed the standard. This will result in  a higher grade, if they pass more standards. They can’t go down in their grade, unless they abuse the system repeatedly by not preparing for retakes of standards quizzes. Quizzes are now 35% of the grade, equal to tests.  Intended consequence: students know what they are quizzed on. Students prepare appropriately. Success rate? I think it is working for many students.

Last year’s tests – students who failed could take an alternate version, after studying with me. Something of a nightmare, and limited success for many students. They scored the same or lower, even after studying with me. A few did improve greatly and worked their way out of the fail, study, take a retest, system. Tests were 50% of the grade.

This year’s tests – you cannot retake a test. Tests are 35% of the grade, equal to standards quizzes. Thus, the primary preparation for the tests is equal in value to the tests themselves. This takes some pressure off of the students, and seems fairer to me. Intended consequence: My life is much more sane. It is much easier to write, reteach, give, and grade a short, straightforward quiz. My tests are like mini-AP tests, and some students were so far behind that studying the failed test was too big a task for them at that time. Studying standards quizzes one standard at a time breaks it down to a task they can manage.


I am keeping track of standards in a spreadsheet. The grading formula is this

Your Grade  = 50 + (Your Standards Score)/(Total # of Standards)

So, a student who averages a 1 on all standards has a 75% on quizzes. This seems much higher than they might have with points -remember, they are not getting correct answers on anything, they are just showing me they understand part of the process. All 2s would be a 100 average. For that, the student must be getting correct answers and showing that they understand all of the process.  .  .

The students are supposed to keep track of their progress, and they can apply to redo standards at our A&E (somewhat unstructured) time using a google form. Since we are on block scheduling, I am having some concerns about sharing quizzes. I have to write a lot of versions and keep them different enough so that the next day’s classes don’t know EXACTLY what’s on the quiz. This is going okay, but could go better (I suspect some students of cheating, in other words).

More updates on this later.

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Bare wires

In the last couple of years, I have made good use of the “bare wire” lab for electric potential difference. I first learned a version of this lab in the Modeling curriculum for electricity and magnetism. In this activity, students measure the potential difference of bare wires connected to a battery pack, but not connected to anything else. Lab2_Quiz_Quest1

This is extremely helpful in developing the idea that a wire can have zero potential difference along its length. And in developing the idea of potential difference being a difference between two different points.

Then, students connect a long bulb and a round bulb to the battery and repeat their measurements.


Finally, they make a graph of potential versus position.

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SBG Homework only?

Tell me this is stupid.

I haven’t found the time to implement Standards-Based Grading in my classes, even though I went to a great session on it at AAPT Summer Meeting in Portland in 2013.

So, over the break I devised this system for homework:

Objectives-Based Homework.

Your goal is no longer to score points. Your goal is now to demonstrate understanding. Each night’s homework will have one or more objectives. The standard objectives will be as follows:

-HW Objective 1. I followed the physics problem-solving process in constructing a solution to the problems (not exercises) or I wrote a clear, logical answer to the questions in the assignment.
-HW Objective 2. I understand and can restate the major concepts/big ideas inherent in the assignment.
-HW Objective 3. I can clearly identify any of the concepts, ideas, or mathematical applications in the assignment that I did not fully understand.
-HW Objective 4. I successfully solved/answered most of the problems/questions in the assignment.
-HW Objective 5. I can solve a new problem using the same concepts/ideas that were inherent in the assignment.

Homework will be assigned using textbook and online sources. There will be homework quizzes for some assignments. These will likely consist of one or more problems/questions that are similar to the problems/questions on the assignment (HW Objective 3). There may also be questions related to (HW Objective 2). This grade will be separate from the homework grade.

Individual homework assignments will be assessed in one of these three different ways:
– Students will complete a self-assessment, describing their success at meeting the objectives of the assignment.
– Students will submit a homework solution for a peer assessment. Assessment will primarily focus on whether the solution clearly demonstrates understanding of the problem-solving process.
– Students will submit a complete solution for instructor assessment or present their solution to the class. Assessment will primarily focus on whether the solution clearly demonstrates understanding of the problem-solving process.

Assessment of homework for process will be based on articles from The Physics Teacher by Kathleen Harper (http://dx.doi.org/10.1119/1.4752049) and Matthew Trawick (http://dx.doi.org/10.1119/1.3293661), and AIP by Sahana Murthy (http://dx.doi.org/10.1063/1.2820920). Rubrics I created from these articles are attached below.

I would assess on the basis of 2 – Clearly fulfills objective. 1 – Partially fulfills objective 0 – Did not complete or does not even partially fulfill objective.

Have to work a little more on how I’d translate this to grades, but generally I’m pretty generous on homework grades already. Major objection from students will likely come if I remove possibilities for extra credit on homework. Many of them earn a homework grade of greater than 100% under the current system, mostly by completing extra credit test review assignments on UTexas Quest (http://quest.cns.utexas.edu).



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In the last few years, I have started the force unit off with demos, seat experiments, discussions, and conceptual questions. This year I decided to make a summary page for some of the activities we have done. They are first drafts, I can’t draw worth a darn, my handwriting is near illegible, and I unfortunately drew them on scrap paper with some dark images on the back. But, here they are. Not in any particular order.

This is an activity in which a cart with a dual-range force sensor (DFS) is wiggled back and forth in front of motion detector (MD) Students did this as a seat experiment in their groups.


Two strings stabilize a cart on a ramp. When the ramp is removed, the cart is stationary.

Incline Plane

Two blocks are suspended from pulleys with a spring scale inserted into the string. The students can’t see what the spring scale reads at first. This was presented as a puzzle, along with a ranking task of similar subject from this book

Tension Force

An optical lever magnifies the motion of the wall when a human presses on it. this was a whole-class demonstration.

Surface Force

A student jumps off of a force plate while it is collecting data. This was also a whole-class demo.

Force Plate

Several friction “seat experiments” are done with blocks, force sensors, and LabQuest 2s.


A HoverPuck (trade name “Kick Dis”) or a bowling ball is given a brief push and glides across the floor at a nearly constant velocity. This was a class activity, with a number of students participating.


A Newton’s 3rd Law demo with two force sensors and LabQuest2s was a final seat experiment.


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