Over the past two weeks I’ve been doing a lot of new things, and I want to get them down:

#1 Hover pucks

Not only using hover pucks, but revisiting them again and again. We began forces by taking hover pucks out into the hallway and observing, describing in words, and  drawing velocity vs. time graphs for

• Motion after pucks were tapped fairly hard and very hard
• Motion of puck while being tapped once every second
• Motion of puck while being steadily pushed

We visited the pucks again before vectors and projectile motion. We sent them going down one hallway, and when they got to the second hallway, we tapped them in the other direction. Students made predictions and observations, once again using words, but this with pictures showing the trajectory,

We visited hover pucks again when making a bridge from projectile motion to circular motion. How to get the hover puck to move in a circle by tapping?

Beyond just “using” hover pucks”, hover pucks became an anchoring context for conversation again and again. Oh, I almost forgot, before the first time we used hover pucks, students took one of the formative assessment activities from Paige Keeley’s book, “Uncovering student ideas in physical science.” It was the one where there is a list of a dozen or so statement about force and motion that students have to agree or disagree to. I had students commit to answers before, and then revisit after. As a class, we talked about a few sticky ones.

#2  Velocity vs. Time Graphs

This summer, velocity vs. time graphs are the major tool we use all the time. As others have said, velocity vs. time graphs are rich with information. The great thing about velocity vs. time graphs is that you never stop using them.

I think that the first activity with the hover pucks was only successful because we had spent a lot of time the week before working with velocity vs. time graphs. Students worked problems using them. My exams required students to interpret them and draw them. I asked clicker questions using them, both before and after hover pucks, and all the time. Questions included quantitative ones, qualitative ones, and questions that went back and forth between considering position vs time and velocity vs. time.

One last note about velocity vs. time graphs. This summer, on any problem involving forces, I have not once given students acceleration or asked them to solve for it. If they need acceleration, they need to get it from a velocity vs. time graph or from a table with data. If I am asking a question about motion, it is about how much the object’s speed will change in a given time, or how much time it will take to go from one speed to another.

#3  Positioning Students as Authors of Ideas and Equations

To a degree, I have always done this. The first semester I taught here, a student named Ashley proposed the tentative idea that when you throw a ball up with a certain speed, it will hit your hand with the same speed. That idea became known as Ashley’s idea, which students used throughout the year to solve problems via symmetry. This year, a student proposed the idea that finding the velocity of an object is the same as finding the slope on a position vs. time graph. That rule is known in our class as Chelsea’s Rule. We also have a Yalda’s rule. etc.

What I am doing differently this year is framing Newton’s 2nd law as an activity of inventing equations. See in kinematics, the equations are pretty much always the same, but with forces, the variety of equations you can write increases a lot. AND, a single equation can describe different situations.

Typically, when we are working on force problems, my instructions are:

• Draw an interaction diagram
• Draw a free-body diagram (or more) for the object or system you think is important
• Invent an equation or two that describes the relationship between those interactions

In the past, students have had a really hard time when we start writing lots of equations without any numbers. While it is still hard and intimidating, it is much easier this year than before. I think some of this is because I am positioning students as inventors of those equations; rather than their being a right equation that was known ahead of time, which they were merely supposed to recreate.

Tied with this, we have been doing lots of Alan Van Heuvelen’s Jeopardy questions. I’ll write an equation like this on the board

T – (150 kg) (10 N/ kg) = (150kg) (-2 m/s/s)

and students will have to draw the free-body diagram and describe the situation. While there is only one free-body diagram really, there are multiple situations, because the -2 m/s/s doesn’t tell us direction its traveling or whether it’s slowing down or speeding up, so there’s a rich conversation to be had.

I think the Jeopardy questions pair well with the idea of inventing equations that describe situation, and positioning students as authors of equations. Another big thing to note is that forces isn’t the first time we did Jeopardy equations. I introduced them during kinematics as equal, and we practiced them with projectile motion. I even have exams questions with them.

#4 Leveraging History of Physics and Contemporary Physics

This paper by David Brookes and Eugenia Etkina has changed the way I think about thinking about force, learning force, and teaching force. It’s changed my thinking in a lot of ways, but one influence it has had is in helping me talk about students’ difficulties learning through the lens of history. This may sound crazy, but I explicitly talk with students about the words force impressa and force viva.  I talk about this on the very first day after we’ve done the formative assessment and hover puck activity, and students are revisiting their initial ideas.

In talking about current days physics, I am doing a better job of framing the work we are doing in terms of current research. This is a perhaps a contrived example, but I think it still helps. We do this lab–one that I don’t like all that much–where students use uniform circular motion data to determine the mass of a ball. I frame this lab as involving the same set of ideas that astronomers use to study dark matter and in finding planets. (OK, it’s not exactly the same, but close). We talk just a little about how we measured the period of the ball going around, and how Astronomers measure the period of planet going around a star very far away. I didn’t make a whole lecture of it, and I wasn’t trying to sell the lab as something cool. It’s just a little thing that helps put our class in contact with larger participation in physics.

I also explicitly talk about the history of physics with Galileo. I spent the early part of the summer reading all of Galileo’s Two new Sciences.  We talked about Galileo’s definition of uniform motion and why he changed it. We examine data and try to make sense of what Galileo meant when he said falling objects follow the odd number sequence. The more I know about the history, the better I find myself able to teach that physics.

#5 Working “problems” with data gathered in class, rather than contrived made-up stuff

Instead of working on some circular motion problem that I thought up, we get a buggy going in a circle with a string. We try to figure out how much tension is in the rope, and students help decide what data to take and help take data. I even have more than one students do the timing and the distance measurement, so we can do uncertainties if we want. I’m doing a good job of doing this quickly, and not dragging it out and making it a lab. It’s just a problem. Sometimes, we’ll try to verify our answer by taking more data; but I don’t have to if we are pressed for time.

#6 At-home experiments and in-class everyday object labs

I’ve had students share experiments with family and friends (dropping paper and book). I’ve had students make predictions and make observations (running key drop) at home. I’ve had students grab everyday objects and share observations and thoughts online (one where students had to get two pairs of shoes and describe what they notice about each that’s informing their decision about which has better traction). In class, students brought their shoes, and we did a lab to calculate the coefficient of friction between shoes and the floor.. I think I got this from Frank Noschese, but can’t find a link.

I have a goal, which is to help break down the walls between my class and the rest of their lives. I do this by asking them to share their learning with others, and to bring those others’ ideas back to class. I ask students to bring stuff to class into do experiments on. I ask them to do experiments at home. Maybe, just maybe, it will make a small dent.

#7 Bridging Analogies:

This year I did two of the bridging analogies described in this paper by John Clement. We did the Normal Force one and the Friction one. Because of time, one of these was done more teacher-centered than I would have liked.

#8 PhET Simulations

Right now, I am mostly PhET simulations using these for “lecturing”. I used moving man to introduce the number line as the system we are adopting for describing linear motion. I also used the vectors simulation for formalizing our observations in the hallway (with tapping hover puck in orthogonal directions).

I imagine I could get students more involved in the future, but for right now this is how I am making use of the simulations.

#9 Online Videos from Veritasium

I had students watch the Misconceptions about falling objects video and Derek’s Three Incorrect Laws of motion video. They watched them home and had to write up specific reflections.

There are multiple reasons for this, but one is to supplement our text, but another is to learn through refutation text (or video).

#10  Mindset Conversations

So far this year, we have talked a lot about learning how to learn. I have been most encouraged by John Burk to make this an important part of my class. A comment here describe a bit of what I have done so far.

Oh, and of course, my last post, about interaction diagrams.

** When I read all of this, I have think to myself, “How in the world did we do all of this happen in two weeks?” I have no idea…

Oh, right, and don’t forget about standards-based grading!

This post represents where we were a week ago. The quotes below show where we are today.

“In the case of the dropping textbook and the ball of paper, the textbook has more weight, but it is more resistant to moving, so it will take the same to hit the ground as the paper (which is less resistant to the downward motion).”

“The gravational pull on the heavier object (the medicine ball) is more than it is one the lighter object (the basketball). The reason why they both hit the ground at the same time is because the inertia on the medicine ball causes it to resist acceleration so it needs more force to come down.”

“The gravitational pull on different objects is not the same. Weight tells us this because the heavier object has the tendency to pull harder towards to earth. Also, the more inertia a certain item has, the harder it is to get it to accelerate and the opposite with lighter objects.”

“Objects that are different weights hit the ground at the same time when dropped from the same height. The heavier object has a lot more inertia (resistance to change in motion), so it takes and effort to get the heavier object to move as fast as the lighter object.”

“Even thought objects accelerate downwards at the same rate, the heavier object takes more force so that both will accelerate at the same constant.”

“I didn’t realize that the bigger ball had more force than the other because it is heavier it apparently has more inertia so it takes more force to pull the ball to the ground.  I thought since they both hit the ball at the same rate that they would both have the same forces acting on them the same.”

“So I already knew that both balls were going to hit at the same time, but I didn’t know why.  I previously thought that they would fall at the same rate due to same force of gravity. Prior to this class I thought that the heavier ball would fall faster due to the mass. But, heavier ball has a larger force. Although the ball is heavier and has a higher force, inertia slows it down making it land at the same time as the smaller ball.”

“I thought that the two balls had the same force since they hit the ground at the same time. I thought the same force would have to be pulling on them for them to hit the ground at the same time. But I’ve learned that since the ball has a greater mass, then it also has greater resistance to the forces pushing on the ball.”

“It takes more force to get the heavier fall to fall at the same rate”
“Both of the balls have a speed that is constantly changing. Most people think that their speeds were constant but they arent. I also learned that a heavier ball has more of a force than a lighter ball. ”

” I would think that the mass would increase the force, lessening the time it takes to hit the ground, but I am still confused.”

“objects change in speed during free fall, but the acceleration for both of the objects is the same. Also, I learned that if a heavier ball and a lighter ball are dropped at the same time, they will hit the ground together due to the fact that the heavier ball resists acceleration.”

“I thought about the force being greater on the heavier medicine ball, and can see how such a simple question can cause confusion on many levels – because one would think – “Yes, gravity is the same throughout the Earth so obviously they have the same force” type deal ;-)”

“It takes more force to get the heavier ball to accelerate at the same rate.”

“I felt like I knew that they would both hit at the same time however now I do not know exactly why this happens.”

“Even though the medicine ball is heavier than the basketball they still hit the ground at the same time but the medicine ball has more force on it. Even though it has more force it still hits the ground at the same time”

I asked students to watch the Three Incorrect Laws of Motion video and to then discuss each one and how they are different that Newton’s Three Laws:

Here is what one students wrote about Newton’s 2nd Law:

[The incorrect law is that ] an unbalanced force causes an object to move with constant velocity (F=mv). This is untrue because F=ma. Changing the force causes the object to accelerate, so the velocity is changing.

It’s interesting, isn’t it?

 

My favorite responses from the key-drop at-home experiments… I’m reminded at how complex the task of observation can be.

After the waste basket. I think this will happen because normally when i let things go while running, they tend to fly “backwards”. So if I release the keys in front of the waste basket then the keys will fly backwards into the garbage can… No no no no. I had it backwards. Things released will continue forward. So when I did this I released it from behind the garbage can and it ended up traveled in a bit of an arc into the garbage can.

 

My keys are pretty heavy, so I’ll choose right above the basket. It worked for me!  Landed in the trash can that is, makes sense but if my keys were lighter I would drop them before the trash can so they would arc into it.

 

After the basket, because I feel like the wind and speed from running forward will drag the keys slightly backwards… It was actually before the basket! I feel now that it is because there is so much momentum moving forward you must drop the keys before

 

I think that if you are running past the waste basket that you should drop your keys right after you pass the wastebasket. Since you are running forwards the keys will go in a diagonal and go into the basket…  No it is not what I expected. The keys would go into the basket if I dropped them before the wastebasket. The keys obviously aren’t going to go backwards when I am moving forwards.

 

I PREDICT RIGHT ABOVE, BECAUSE YOU WILL BE RIGHT THERE WHERE THE HOLE IS. IT WAS RIGHT AFTER. IT MAKES SENSE, BECAUSE THE MOVEMENT FORWARD MAKES THE KEYS PROJECT BACK A LITTLE BIT.

 

I asked my roommate, [so-and-so] (she says hi!), to perform this experiment with me. We discovered that we needed to drop the keys before running by the wastebasket in order to make sure the keys landed in the wastebasket. The forward force of running with the keys towards the wastebasket continues slightly when you let go of the keys. Therefore, they continue to travel forward for a short distance while in freefall.

 

As i thought i had to drop the keys just before i passed the basket so the that they didn’t go past the waste basket.  I would like to think that since your carrying the keys they still have a velocity even though their not moving, so once separated from your hand they take on the outside acceleration and start to gain its own velocity for a different direction.

 

When I got my family involved with this activity, they had predicted that I would have to release my keys right above the wastebasket. They said that the weight of they keys and the momentum wouldn’t matter due to the fact that the keys weren’t being thrown. After testing our hypothesis, we found out that what we originally predicted was right. If you run holding your keys out then you would have to release the keys right above the basket in order for the keys to land in it. Releasing the keys before the box and after the box would land the keys in those spots before or after the box.

Week one standards this summer were the following:

#1: I can re-express quantities using different units

#2: I can distinguish among position, distance and displacement

#3: I can relate an object’s acceleration to how its velocity changes

#4: I understand the direction and signing conventions for acceleration during free-fall

Next time, I want something more like:  I can distinguish between average velocity from change in velocity. 

There are just too many times that we are thinking through problems by considering these kinds of quantities

1/2 (Δv) (Δt)

Vavg (Δt)

Δv/Δt

Δx/Δt

The reason I am saying this is because on our first exam, much of the feedback I gave out was about the distinction.

 

 

I always ask for feedback from students right after the first exam before they know how they did. I find the three questions below to be very useful in guiding students to be reflective about their learning and our class. Every time I do this, I am taken back by how thoughtful college students can be about their learning.

All and all the biggest complaints from students are about the reading material itself and the computer exercises. Last semester, students also complained about the computer exercises. I’m not a big fan of either. Students do seem happy about standards-based assessment and explicitly talking about multiple strategies to solve problems (especially ones that don’t involve plugging into equations).

I’ve put in red the things that really stand out to me.

What are we doing in class that is helpful for you learning? Why is it helpful?

Doing problems during lecture and showing how to work through it different ways. Being able to retake the content standards so you can see where your problem is and work through it. Working in groups in lab is helpful that way there are more people to help you understand it.

I love how it’s structured so you’re in charge of mastering 4 main topics a week. It makes it really easy to wrap my head around knowing exactly what I need to learn instead of a teacher saying, “Oh. Learn chapter 8.” … And I also love the side paths, like learning about how to learn, mainly just because psychology is so interesting to me.

Working through a lot of problems and going through in detail and step by step. Working together in groups. Finding the wrong way to do the problems.

I get to communicate what I think. Do hands on activities. And the card questions.

It really helps when we work in groups. I am able to better understand things better when I can discuss/converse with others about the problems**

Group activities. Reason being we get to share ideas, notice errors and correct them. Especially in this course, the group work helps a whole lot. Having to retake standards are also helpful.

The standards. If I get the problems wrong, it makes me want to keep working to get it right.

Relating the problems to actual events in life, the ability to mentally picture what is being discussed helps.

I like the way things are broken to where it makes sense logically and not just formulas.

When we go over problems, it helps me to understand how to successfully do the problems. The way that you grade quizzes and give them back quickly is also helpful.

Everything. Working out problems and going through scenarios are very helpful, because it helps put my everyday life into perspective, so that I question things and strive to figure out different methods for answering the same question.

You simplify things. You don’t just give formulas and make us plug and chug. I understand the “story” to each number I’m plugging in.

I find that going over example problems is helpful because it makes concepts easier to understand

The review and group work we do is very helpful!

We talk about a couple of different ways of doing things to come up with correct answer. This helps, because I can use the different methods.

The real life applications and working it out on the board. Doing the multiple choice questions also help me learn because I hear others’ opinions.

The lecture are helpful because it translates the “greek” of the online content to plain english and relates it to real life. Labs are actually fun.

Working out problems on the board really helps me learn to solve problems. Group discussion about problems help as well, because I get to see mistakes people make so then I won’t make those mistakes.

When you give an example, work it, then give us another for us to work is helpful. It gives a chance to see it and apply to see if I have really learned it. The activities and labs also allow me to see why things are the way they are.

Working out practice problems is helpful for my learning because it gives me practice and helps me to see how to do problems that are similar to the homework.

In class, when we do example problems and you work them out step-by-step that is helpful because it allows me to see the steps I need to take.

The quizzes are helping because it makes me practice.

You work and explain problems giving us different ways of working them. I am not always the biggest fan of huge equations.

Having an instructor who really explains is helpful. Being in groups that work well, too!

Showing a multitude of ways to solve one problem. It gives me a working perspective.

Going over problems is really helpful. I like that you give us time to answer and then go over it. I also like you show different ways to do the problems. The most helpful thing is you explaining the units in the equations. So that I know why I am using them and what the units mean.

I find the  quizzes because it helps me gage how well I retained the material, but since they aren’t graded, the quiz isn’t stressful. Going over problems in multiple ways–not just plugging math equations helps me visualize what is going on. So Ican better apply the math later.

All of the group discussion helps me. Hearing other people’s strategies to solve problems help me find better ways to solve them. If I talk to someone about a concept, it helps me remember it more. I also like the questions that we hold up cards with.

What are we doing in class that’s not helpful for your learning? Why is that not helpful?

I can’t think of anything that doesn’t help me. Overall, I like lecture and lab much more than the online textbook.

At this point, I’m not sure I take away much from the computer exercises in lab.

Nothing

Reading the lecture book online. Although it introduces ideas, it confuses me more than it helps me.

None as of now.

Everything we do helps.

When the class votes on right and wrong answers. You ask people how they came to that answer and it makes sense; right or wrong. It can sometimes confuse me later on when thinking which one was right.

It is not helpful when you present multiple ways of solving problems because I get confused on which methods.

I think the computer work isn’t really helpful. I would do more groups @ the tables.

The quizes on the computer during lab is not helpful for me. Also, the nightly quizzes don’t really help me to understand what is going on in class.

I think the computer activities aren’t helpful. Things that I really learn from and apply to others aren’t nearly based on the computer activities.

I think reading helps somewhat, and I know it just part of any class, but I better understand it in class

The online lecture are “meh”, reading and using the exercises is good at best, but I learn much more from in class time. Online content seems harder to understand.

The computer lessons aren’t very helpful because sometimes the questions are very convoluted and difficult to understand.

Once we learn a couple of ways to do it without equations, the equations just confuse me, and I’m not good at memorizing the equation,

I don’t feel like it is helpful to read all the lectures and practice problems before class. Often they confuse me with all the equations and leave me feeling deflated. When I go to class, I feel that what I thought I knew is wrong and almost completely relearn the concept.

I can’t think of anything.

Everything we do is extremely helpful.

Nothing

Everything we have done has been pretty successful.

I don’t have any complaints.

Narrowing in on the formulas and math. This does not happen often, but we can sometimes get tunnel vision with respect to what numbers are rather than what they mean.

The reading. Sometimes I don’t understand what I’m reading.

The readings. Sometimes. Sometimes the reading tends to be confusing and not easily understandable.We don’t go over the reading in class.

** However, after taking the exam, I feel like I may be basing too much of my confidence on the group work. When it comes to doing a problems by myself, I blank. So although it is probably a personal task that I need to do on my own time. I need to do problems on my own.

I can’t really think of any.

Switching through equations is confusing at times.

A couple of times, it almost seemed like drastically beating a deadhorse, and it was little hard to pay attention.

We aren’t given adequate time for the lab write-ups. I feel sometimes like I’m just going through the motions and not grasping it, just so it’ll get done.

Is there anything else on your mind? Something you’d like to tell me? Something you’d wish we did do that were not?

What really throws me off is how complicated the readings are compared to class. The readings confuse me, especially when I have a question, I have no way of finding an answer in the readings.

I enjoy the random advice you give.

I wish you were grading on a curve.

I really liked having practice test–that was a lot more helpful that trying to guess

I love your passions for physics and allowing me the chance to succeed. Also, the videos we watch helps me understand how to learn.

I feel pretty good about this class.

It is difficult to balance all of things going on in my life, one at a time would even be difficult.

I am very worried about the discrepancy between what we are going over in class and lab and what re read each night. Which part of class should I focus on?

I enjoy that you learn and talk with us, not as much you talking at us.

It is not hard to get up and go to class, unlike my other classes.

I appreciate your enthusiasm for learning and teaching. It makes me want to try harder and really learn for a reason.

What helps me most I practice problems and doing them multiple times. It would be beneficial if homework was turned in everyday, so that I could spend more time learning how to solve problems and less time on the quizzes.

To me, the readings are confusing, because they present the material so differently than you do. I like the way you present it better.

I can tell you really enjoy teaching and it makes me eager to learn. I’ve taken physics before and this time its’ much easier. Everything fits together and makes sense.

I really like being able to retake any quiz. It really forces you to learn the information. I also like how fast grades are given back.

It would be nice to see some of the homework problems worked out, but then again, it might make me not do them the night before.

Could you possibly go over more homework problems from the book?

I don’t like the way the online text teaches. It is very hard to understand because they seem to make solutions to problems much more difficult than they need to be. It throws me off to have such a difference between the textbook explanations and classroom explanations.

One thing I really like about standards-based assessment is that learning to do it is much like riding a bicycle:

#1 When you see someone else doing it, it looks like a lot of fun. But it also looks scary. Because you can see right away that so many things could go wrong. The combination of fun and scary makes it compelling.

#2 When you aren’t doing it yet, the only people you see doing it are mostly people you look up to–your big brother, your mom. The fact that these people are doing it makes it compelling.

#3 Getting started is the hardest thing, but then your off and learning; because once you are going, you learn by the mere act of doing. The bike keeps moving; the re-assessments keep coming.

It’s really this third item that I want to talk about. One of things that I really like about doing standards-based assessment is that amount of things I am learning through doing it. There are several reasons for this. First, I am looking at 32-50 individual pieces of assessment per day that I’m NOT grading. I’m looking at the student work and deciding “Yes ” or “No”. Looking at the student work through the lens of, “Have they demonstrated understanding here?” is way more generative of learning for me than, “How many points should I give (or take away) here?” Because of research, I am more practiced at looking at student work and asking questions like, “What is the student thinking here?”, “How did this make sense to them?”, “What about this context made this response so likely?” And while these questions are important, they are different than asking if the student work should count as evidence of understanding. With standards-based assessment, I get lots of practice at this new skill.

Second, I have to re-write assessments constantly that will hopefully assess one isolated skill again and again–a quiz that hopefully cannot be answered correctly by just memorizing something from past quiz. I end up having to write about 5-10 different assessments for each standard.  There are a lot of constraints in writing these assessments:  keeping it a valid measurement of skill under question; keeping it somewhat isolated to that skill; making it different enough from previous quizzes; making sure it can be done in a short time frame; etc, etc. I like the fact that I now feel comfortable writing quizzes off the top of my head. While I occasionally make less-than-superb decisions in writing assessments, I am much better now than I was 6 months ago. I rarely write an assessment that students will get right without understanding. I feel comfortable knowing how to make any assessment slightly easier or slightly harder. Sure, sometimes I goof up. But that’s sort of my point. I learn by making those goofs and thinking on what went wrong with that assessment. How were students able to answer correctly without really getting it? Why did no one answer that one correct? Sometimes it means that I wrote the quiz bad; other times it means there’s some new issue about student learning of that skill that I’d never really thought through before.

My advice to anyone thinking about doing standards-based assessment is to do it, even if a little bit. While I think there may be people who say you have to do JUMP full into SBG to make it work, I’m not sure that’s true. Last semester I dipped my toe into it, replacing reading quizzes with standards-focused quizzes. Students valued it, and I learned from doing. This summer I expanded it. My course is still not fully standards-based. Students get credit for doing pre-class reading questions (“graded” on effort). Individual students labs are graded on a rubric, but a part of their lab grade is now based on lab-skill standards. I’ve made my rubric aligned with the standards, but the lab write-up still gets a grade that can’t be changed; while the lab standard part of the grade can be learned at any time. I still have exams; they are just tightly aligned with standards.

There are lots of good reasons to do standards-based assessment, but one reason should be the opportunity it provides YOU as the teacher to learn to become a better teacher. The practice itself is generative of better practice.