Theories of Color

Theory #1 (Light absorbs color from surfaces, and then some bounces off):

Light from the sun is, for the most part, colorless until it comes upon a surface with color. The sun light that hits the surface absorbs the color from the surface, and when it bounces off the surface it carries that color with it.

Theory #2 (Surfaces absorb some light colors and reflects other)

Light from the sun has all the rainbow colors (like ROYGBIV). When light hits a surface, some of the color gets absorbed into the surface, while other colors bounce of the surface.

Theory #2a  (reflected colors represent color of objects)

The color that we perceive surfaces to be is due to the colored light coming off and entering into our eyes, creating a “visual perception” of color based on the light that enters.

Theory #2b:  (absorbed color represent the color of objects)

The color that we perceive surfaces to be is due to the color light that stays with the object. Because that color is absorbed into the material, it gives that material the visual effect of having that color.

The general consensus is that none of these theories seems adequate and all of them have problems.

We have many arguments for and against, so here is just a few examples for each theory:

Theory #1:

Arguments for:  Colored objects left out in the sun become sun-faded. When you shine a flashlight on colored paper, light of that color comes off.

Arguments against: Prisms and rainbows suggest that sun light already has all the colors. White light from the computer screen isn’t colorless, its made of red, green, and blue.

Challenge: Explaining how color shows up with things like CDs, rainbows, which don’t have any instinstic color for light to absorb.

Theory #2a:

Arguments for:  Prisms and rainbows suggest color is already in sunlight. When you shine a flashlight on colored paper, light of that color comes off.

Argument against: Some colors like grey are not a rainbow color, so in the theory it would seem grey can’t be reflected off, but we grey things exist.

Challenge for: Explaining how surfaces “know” which colors to send off and which to absorb. There isn’t a “gate keeper” person there, telling which colors get to stay and which colors must go on.

Theory #2b:

Arguments for:  When things get colored in everyday life, its because the surface absorbed that color and the color stayed there. This is how painting works and why red wine stains.

Arguments against:  Blue light comes off of blue things (we’ve seen it on our hands when shining flashlights on blue construction paper)


A student asked this question at the end of the day:  If you get rid of all the lights in a room, do the objects still have color?

I’m thinking…

We are deep into ontology: What is the nature of light? What is the nature of color?

We are deep into mechanisms: What are the interactions that can occur between light and materials?

We are also deep in theory-driven science: What evidence can we marshall for and against theories?

Skillsets for Working in Small Groups

One of the skill set I am realizing that many of the future physics teacher here lack is how to productively work with others on challenging physics tasks. I have been trying to be more explicit about how I model effective group work with them, but part of that means that I need to be more articulate to myself about productive group work.

So what skills do I think are important? Geez. There are so many, and they are hard to articulate. But here are a few that I think are really important.

  • Being willing to offer tentative ideas, even when you are unsure. Being willing to offer ideas as tentative, even when you are sure.
  • Finding a balance between “taking some initiative” to get going and “going with the flow” of where others are going.
  • Inviting others to say something, especially when they haven’t in a while. This seems to imply that you have a skill set for monitoring who is and isn’t contributing.
  • Asking others to clarify what they have said, or say more about what they just said, or ask them to explain why they think something. This comes along with some skill set in which your tone of voice is inviting not judgmental.
  • Re-voicing others’ ideas (“Let me see if I get your argument, you are saying…”). This comes along with a skill set of *listening for understanding*, not waiting for your turn to talk.
  • Noticing and pointing out when two there  are different answers or ideas that have been presented. This means you are not only listening for understanding, but monitoring across understandings for differences and similarities.
  • Holding oneself, the group, and progress accountable to “reasoning” and “arguments”, and holding “reasoning” and “arguments” accountable to *consensus ideas*, whether they be canonical physics ideas.

I’m curious. What do others think are important “working on school physics tasks” skill sets?

Thinking in School? Who knew?

The undergraduate TA in my physics course is, I think, coming along quite well. Yesterday, the TA said something like, “This class, the way you are teaching it, is a lot harder than when I took it… I have to think a lot more in this class… I gave up on thinking in school years ago. This is the first class that I’ve had to think for in a long time.”

This reminded me of this quote by Bertrand Russell:

Never try to discourage thinking for you are sure to succeed.”



Post-Tenure Dream Class

Get the following kinds of people together: cognitive scientists, painters, computer scientists, tattoo artists, physicists, photographers, biologists, textile manufacturers, psychologists, etc. Teach a class about images in the context of art, technology, science, information processing, etc. Topics to include pointillism, light, photography, image processing, color mixing, perception, anatomy, history of art, knitting, tattooing, optical instruments, bio-luminescence, etc.

One day…


Physics: Day One and Two

Day One:

Learn everyone’s name…

Marshmallow Challenge (Intro rules, ask if any clarification, 18 minutes, circulate, measure, kudos to winner)

Small Group’s discuss and whiteboard what contributed to success and unsuccess (circulate and re-voice, nudge if necessary)

Whole class discussion… I write at board, re-voice as doing so.

We watch the Marshmallow video, pausing at key times to predict / discuss

Introduce class Motto: “Fail sooner harder”… explain how relates to Marshmallow challenge

Discuss syllabus, especially purpose of standards-based grading–> link to activity and motto

Go over “required” slides… end class with names again.

Day Two:

Start class with names again (foreshadow that someone else in class will have to do names at end of class… sell it up as who is up for challenge)

Hand out ABCD voting cards, explain purpose.

Watch “How to Study in College” Video, pausing to predict / discuss (small groups and whole class). First use of voting cards, so model for them how to use, and give feedback on use.

First Physics: Use PhET Simulation to introduce number line, focus on idea that all semester we will be using the number line idea. Introduce notion of “instantaneous position”… keep this brief (not rushed) and focused on key ideas.

Introduce concepts of position, distance, and displacement (power point)

Clicker questions from PPT (link back to concept of deep processing from video we watched… remind them that my job is to help them deeply process material, but that by end of course they should be better at deeply processing material without me)

Introduce average velocity as a “tool” we can use to investigate ANY motion (PPT)

Give students two data sets in table (one constant, one not constant)–> have students practice using the tool to investigate … brief discussion about using tool, and idea of uniform motion (tool always give same value no matter what interval we use, early, late, large or interval… foreshadow that next week we’ll be studying non-uniform motion in depth).

Example Problem (mile-markers back and forth): introduce annotating word problems, introduce motion maps, introduce good labeling and coordinate systems,

Ask class question, “What are all things a GPS device could tell us about this motion?” — they talk in small groups. Whole class while Brian makes list on board of things said. Add anything missing that I want to calculate. Make a big deal about anything they add that isn’t what physics text talks about (e.g., average speed while moving). Ask question, “Which of these things is immediately obvious because how we’ve drawn a careful diagram?” —> Do those quickly, and point out how important good diagram was in doing this. Carefully work out one’s that are not obvious, like average velocity / average speed. Focus on their verbal interpretations, focus on why average velocity is negative, why average velocity magnitude is less than average speed.

Students get whiteboard problem (a different mile-marker problem) with prompts to copy words, annotate, draw diagram, draw position vs. time graph, and solve for all the things a GPS could solve for. As circulate, monitor for “rushing to solve problem without being careful”, and give specific praise on clarity, collaboration, etc. Decide whether a whole class discussion is needed, keeping in consideration time.

First SBG quiz. Remind them about standards-based grading and purpose of quizzes (information about what you understand and are able to do by you self. We do a lot as a whole class, and a lot with your  group, now it’s time to “fly solo”.)

Lab: Show students buggy, and what they have on table (meter stick, timer) Tell students they have 5 minutes to determine the speed of the buggy, and record their answer at front board. After, discuss a few different strategies (fix distance, measure time… vs fix time and measure distance), and discuss purpose of taking multiple measurements.

Tell them you want to do lab, a different way. Show them the “event” button on the timers. Model for them how you can use the event timer to take a series of measurements. Introduce the stickies to put on the floor to make a coordinate system. New challenge: Start the buggy somewhere not x = 0, take data in order to make a plot of position vs time… Let them go off, making sure they understand how to use event timer, and the purpose of coordinate system. Once wrapping up, tell them we are going to further investigate this graph next week using the average velocity tool, in order to decide whether its uniform motion or not, and to learn how to use excel to make plots, etc.

While students are doing lab, find some time to grade quizzes and immediately hand back. Remind students its their responsibility to keep track of their assessment progress.

End class asking someone to volunteer to try their hand at doing everyone’s name.




Feedback in Physics

As usual, I ask students for feedback after they have taken the first test, but before they have gotten it back. Below is what they have to say. Lots of interesting themes. I have to say that the “mindset” curriculum has huge pay offs in terms of student learning, student attitudes, and student self-awareness.

What do we do in class that is helpful for your learning? Why is it helpful?

The quizzes are good. They make me focus more on material now while its presented in class.

Making sense of the equations so they are easy to understand. It helps me to understand why I’m doing what I’m doing.

Example problems reinforce the methods. Quizzes allow me to learn the right way approach problems and then test it.

Hands on problems help me understand. The way you explain everything throughly helps me learn fully.

Whiteboarding problems with group, rather than figuring it out on my own. It helps me sort through my confusions.

I love working in groups and being able to draw out the problem on the whiteboard. I tis helpful because I normally don’t ask a lot of questions.

I like talking through problems with my group.

Instead of just learning equations, you give us reasoning behind them. That makes sense to me and helps me remember them better.

This class is more than just a physics class. This class helps me to find interest in learning, even with things I don’t want to learn.

Practicing problems in class helps a lot. Practice makes perfect.

Working problems as a group, help me see if I’m making a mistake-both where and why.

I love that we over multiple problems to understand a concept. What also is helpful is when you have break into our groups and have us write out every step at the whiteboard.

The clicker questions. Practice problems with w/ walk by assessments. This increases understanding. Example plus group work are great, too.

Your enthusiasm helps me keep focused on the material. The biggest thing that helps is working through problems with others in class. This is helpful because it helps me work through difficult things with other and see how they work it as well.

Showing examples of how to work problems without just picking a formula and plugging in numbers is helpful, because it shows what the problem is really asking and what we are trying to do and why.

Group work is helpful because we learn from others.It is helpfuly because you can explain to others reasoning in finding solutions.

The labs that point of the dynamics behind most everyday objects like hover pucks.

Group discussion provokes thinking and gives us a change to develop our own answers.

The hands-on instruction and conceptual learning.

Practice problems and quizzes that are akin to test questions.

Group work is very helpful. Talking to other people helps solidify my understanding.

Working and learning how to problems on the whiteboards, and discussing during class.

This is a good lab and the info is clearly communicated.

Working in groups with whiteboards really helps me learn. Being able to discuss problems with other people helps me understand better.

I get more from working out equations in my group and being able to hash out ideas I’m struggling with.

Hands-on activities; it gives my brain time to digest what we just went over (e.g., the hover pucks)

You discuss topics outloud in class that changes my thought process, and then we work thru problems, both visually and verbally to solve and bring understanding to topics.

I like the hands-on projects.

What do we do in class that unhelpful for you learning? Why is it unhelpful?

Nothing is unhelpful. Maybe a few extra reminders about test formatting.

The labs.

The quizzes hurt me when it comes to learning, but it’s not a big deal.

Nothing really.

Labs. I know we have to do them. I just don’t feel like we are applying what we’ve learned when we do them.

I could benefit from would be some one-on-one tutoring, but I know that’s offered outside of class.

Explain more how to use the equations.

Sometimes we get off subject for too long-questions that have nothing to do with the assignment.

Quiz being taken in class. If we took them early, we would have an idea where we are before and after the lab.

I wish we went over the homework.

I wish the assessments were more difficult. I understand why they are what they are.

The “lab” lab part. Sometimes I feel that they are a waste of time.

The lab activities. I don’t get anything from them.

Sometimes we go really fast.

The actual labs aren’t helpful.

When you ask us to diagram a problem, annotate it, but don’t actually solve it. I feel like you stop the learning process for me half-way.

Annotating problems without solving them can get repetitive-more annoying them helpful

Sometimes I feel like I didn’t learn a thing, and have to wait for closure until the next class.

Is there anything else you’d like to tell me? Is there something on your mind? Or something we don’t do in class that you wish we did?

I sought outside help to determine exactly what force is. We still haven’t really figured it out.

We should have class outside more and do more hands on examples.

Before it gets cold, we should have class outside.

I don’t do well on quizzes. I know I need to do the homework and have a chance to digest the info to do better on quizzes.

You’ve been the most influential teacher I’ve ever had.

More group problems if possible.

I really do like this class, now that I have a better understanding of it. I just wish we didn’t have a quiz every class.

I’m batman

I recommend continuing talking about and teaching us about how to learn.

I wish we could do more group work.

More experiments and applications

I realize now that I need to learn more about how to learn effectively (for life).

I felt extremely prepared for the exam-very comfortable with the material. I am very glad to be in this class.

I like learning and doing a lot of problems and talking about strategies before the quiz. It’s hard for me to learn straight from the lecture notes.

Could we get some optional difficult problems to help understand and process more in depth. I always like a challenge.

We could use a little more time to complete the labs.

Trying to Get Better at Feedback

This semesterI’m committed to improving the feedback I give to students. Specifically, I’m trying to focus on the following:

Revoicing (stating back to students what I see them as saying)

Summing up with a word (giving a word to describe what they are doing)

Seeking clarification or specificity (“do you mean this or that?”)

Describing (“I see you doing…”)

Asking for help from them (as a reader who is trying to understand)

Connecting (pointing to or asking about a possible connection between ideas)

Linking to Practice (pointing out scientific things they do)

Example #1 (Describing and linking to practice)

“Using evidence to drives changes in your ideas is a huge part of science, and I see you doing that here.”

Example #2 (Describing, linking to practice, and summing up in a word”

“This is another really scientific thing to be doing–keeping track of how your thinking changes and why. In psychology, they call this ‘meta-cognition’ or thinking about your thinking “

Example #3 (Re-voicing, connecting to practice, and summing up in a word)

“I agree with you that you haven’t provided a strong argument against this idea. We’ll need to… one reason is because in science you can’t really prove that you are right 100%, so you have to work to convince that other ideas can’t be right. This tactic is sometimes referred to as falsification.”

Example #4 (Describing and seeking specificity)

“You say you kinda disagree but also kinda agree. Which parts do you agree with specifically and which do you disagree with?”

Example #4 (describing and maybe implicitly linking to practice)

“I see you not only changed your mind, but you have a reason for doing so.”

Example #4 (re-voicing and asking about a connection)

“Your idea is that when light bounces off objects it takes the color with it, then into the box. Did I get that right?… This makes me wonder how the color gets arranged so precisely (you called it an “exact replica” on previous page). Like, it’s not just a mishmash of colors. I’m curious what your thinking about this might be.”

Example #5 Describing and Asking for Help

“I see these two diagrams here that look they are trying to show me something important, but I’m having a hard time knowing what to take away. What are you trying to show me? What could you write or add to help me understand the ideas here?”

Example #6 (Re-voicing)

“This seems like a strong argument against the shadow idea. The image in the box doesn’t have color, so it can’t be just shadows. Your idea is that the light carries the color, right?”

Example #7 (describing, summing up with a word, linking to practice, asking for help)

“In science, we call statements like this one a “claim”. Often when we make a claim in science, we want to have evidence to back it up. What evidence would you give to convince me to believe your claim?”

Example #8 (connecting, seeking clarification, )

“Here you are using the word “attracts” to describe what the foil does, but earlier you said it just “allows in” the light. Attracting and allowing seem like different things the foil could be doing. Do you mean one of these ideas? Both of these ideas?”

Example #9 (connecting)

“Do you think your idea here is like the over-exposure idea that came up in class?””

Ambitious Teaching: Perspective from Two Pre-service Teachers


“Science is a subject that can be taught through everyday life and interesting situations…The first and most important step to teaching science well is to let students experiment.  As teachers, we must allow students to figure out how to get to the answer on their own.  We must allow students the time to think through processes and eliminate possibilities that can be disproven.  We as teachers must make science “problem solving” rather than just facts that students have to memorize. As the facilitator of the classroom, we should treat our students as scientists.  We should allow our students to discuss ideas, predict, experiment, and eliminate ideas.  We should allow our students to think for themselves and then meet back together as a group to discuss their ideas.”

And Comment:

“I like your ideas on how we should run our classrooms. The problem for me, however, is learning how to carry out all of those characteristics with a sense of balance. Sometimes it’s easier said than done. How do we know when students have experimented enough? How do we teach them to be problem-solvers without being too vague in our instruction? How do we determine when the discussion has run dry and that we need to move on. These uncertainties (which I’m sure will come easier with more experience) along with the pressures of meeting curriculum standards and administration expectations contribute to some of the areas where I could improve in my own teaching.”


Teaching by Telling: A Student Perspective

A student in my class writes in a reflection:

I often feel like if a teachers tells me something and I am confused, they are frustrated. Feeling like a teacher is frustrated with me makes me want to just pretend to know what they mean so they will have that breath of relief because they don’t have to keep telling me or figure out different ways of telling.


Inquiry low down

This year’s inquiry is going pretty well for a couple of reasons:

(1) I have an undergraduate teaching assistant in the class who took the class last semester. Having her in the room really helps. I don’t have to rush around to every group. I let her run some of the discussions. It provides a sense of “bigger” community than just our class, we are more strongly connected to past classes. She also has perspective on this class, the material, and learning the material that I can’t have.

(2) From just more experience and reflection with this class, I have a better sense of what ideas are truly critical and generative for making progress, and how to get those ideas seeded through activity and discussion. While I’m worried about overly stream-lining certain aspects, I think the balance I have is fine for now. Students hold authority and agency in the classroom, but I’m just better at maintaining both the reality and feeling of progress. I want to keep monitoring this, however, make sure I’m not rushing anything or taking away agency.

(3) We have a facebook page that is been put to pretty awesome use for moon journaling, reading reflections, random posts, etc. This has been useful for a lot of reasons–but it keeps me in touch with our class’ thinking and engagement. It also extends the temporal and spatial boundaries of the class.

(4) Students have weekly readings on topics such as children’s inquiry, nature of science, mindset, etc, which help students ‘digest’ what this class is all about. This also provides some variety to our class and connects our class more obviously to their professional lives.

(5) Overall, I feel like I am structuring student presentations better as to not make them overly repetitive. This has been a facilitation weakness of mine, but the “Five Practices Book” has really helped me rethink my goals, my planning, and my facilitation.

(6) I’m doing better at shutting up during discussion… and to mostly only make contributions to seed connections, facilitate. I could still talk less.

I’m posting a little less this year, because I am posting more regularly to research blog.

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