Re-order of Lesson 8

I decided that since I just did the "mini review" using the whiteboards, I'm going to forge ahead into Lesson 8 and 9 and come back to the Class Consensus.

I'm also giving a quiz tomorrow. That should give me a gauge how much understanding the students have grasped (or not) of the material.

Lesson 5 Mini Review Whiteboard

After Lesson 5, I had each table randomly select an Idea Journal questions (#1-6) and write a summary on a white board with SPECIFIC EVIDENCE to support their reasoning. This provided us with a good review and ensured that everyone had everything in their Idea Journals.

Audience members took notes in their Journals.

It is a "mini" class consensus. I am correcting errors and asking questions when there is missing information.


I good homework assignment is questions #1-4 for Lesson 6.

Post Lesson 4 Check-In

Last week we assigned the Idea Journal questions 1-3 and 5 for homework (1. position-time graph idea, 2. speed-time graph idea, 3. strobe diagram idea, 5. acceleration-time graph idea). Students were to make sure in their responses that they addressed the 5 kinds of motion we've been looking at (no motion, slow constant speed, fast constant speed, speeding up, and slowing down).

Today we checked for completion of this assignment. Though homework completion was low, we had students change groups and summarize their ideas on the whiteboard in pairs or threes. I was looking and listening primarily for quality on task conversations between group members and if they were able to explain their ideas to another in their group. I was very excited to hear the thoughtful way they discussed and checked back with their experimental results. Here's a couple whiteboards they created:

If there were places where the speed-time and position-time graphs were the same, we pointed that out and asked students to support their ideas within their group. The most challenging part was speeding up and slowing down as represented on the graphs and the acceleration graph. This makes sense since students have only had one experience with it. They will be building on this first experience in Lesson 4 with Lesson 5 and the simulators.

In the second whiteboard, you can see that the speed-time graph looks just like the acceleration-time graph. There doesn't appear to be a connection between speeding up as acceleration (nor slowing down as negative acceleration). Otherwise, students have shown some solid understanding from this task. One question I would ask this group is: "Is there another way to show "no motion" on the position-time graph?"

4.2 Troubleshooting

We had lots of bumps in our acceleration graphs - I was rarely able to get any as smooth as those posted by Angie. I found that changing the time axis to 4 seconds (right click, graph options) smoothed out the bumps a tad, and took away some of the confusing noise at the end of the graph. I also changed from 3 to 4 batteries in the fans.

I was wondering why constant speed isn't a part of the acceleration graph portion. This is a clearly identified objective - An object that is moving at constant speed has zero acceleration, so the acceleration-time graph is a horizontal straight line at zero. I don't know if students are supposed to come to this conclusion based on the other graphs, or if it just got cut with time etc. I think that seeing this first would help students more readily interpret speeding up and slowing down graphs and reason through negative acceleration, especially as the trends on some acceleration graphs are much less obvious with with all of the bumps.

Inv 4.1 and 4.2

Reviewing the graphs students saw in Investigation 4.1 and asking them to label the motion on the graphs was really helpful. There are students who confuse the position-time graphs and the speed-time graphs; and this seems to be most effectively dealt with on an individual or pair basis. Asking students to explain why they labeled the horizontal line as traveling at constant speed (on a position-time graph) has revealed that some describe no motion as constant (non-changing) speed, and some interpret the horizontal line as the object has motion and is traveling at constant speed.

In Investigation 4.2, students seemed to adjust easily to the error in the directions (I claimed responsibility for the error) so that they were looking at speeding up data in the first part and slowing down data in the second part. Getting the equipment right for the acceleration graphs takes patience; students can definitely do some of this - they should be able to accurately predict what speeding up ought to look like on the speed-time graph. Here's the best slowing down graph I collected.

Wendy's post suggested several trials and looking at best fit interpretations. Here is her set of graphs for slowing down:

Lesson 4 data analysis

4.2 I had the students get data for about 5 "runs" for each graph and make a "best fit" rough sketch. I also had them look at the best part of the line that represents an object slowing down or speeding up.

We debriefed it the last 10 minutes of class and I used "my data" to help them see that the acceleration graph is a horizontal line (positive or negative).

4.1 I reviewed what the lines "should" look like before starting 4.2 in a short class discussion using "my data."

If you want me to email the files of "my data," let me know. They aren't perfect, but do show relatively decent data that are similar to what students will see.

ps-the socks over the old detectors work! And clamping them down helps!

Lesson 4.1 + student roles

Lesson 4.1 went pretty smoothly. I reworked the order of the lesson so that students did all their predicting first for the three types of motion (constant speed, speeding up and slowing down) before using the equipment.

After they took constant speed measurements, we stopped and did a thought check - did they get the results they expected? They have seen this type of motion before, so they should know what constant speed looks like on each of those graphs. This was a great time to readjust equipment and retest if needed.

Students seemed to respond well to being careful with the equipment; but I created roles or jobs for each student to have within their groups. The first is the "reader/checker" who is really the manager of the experiment. When the group is off in the wrong direction, I ask who the reader/checker is. There is the "computer driver" who runs Logger Pro. The "walker/starter" who lets the car go and starts the motion and the "catcher" who stops the car at the end of the track. With four batteries, the fan gets the car going quite quickly, so the "catcher" needs to use both hands. To start with, I have asked students to decide who takes each role and rotated them through the "computer driver" role.

The Logger Pro files in the pickup work folder are named for the Investigation they go with - Part1_Lesson4-1.cmbl and Part1_Lesson4-2.cmbl. Students are getting better about problem solving through the equipment issues.

We got to the part of 4.1 where students are using the tracks for the slowing down motion. Be sure to not let the cart move back toward the motion detector.

Lesson 4

THERE IS AN ERROR IN THE WORKBOOK! It says to open 4B (second progam) but that is for the acceleration lesson!

I set up the tracks and you can have the motion detectors set up at at the 5 cm mark and the carts start at 30 cm for the NEW motion detectors. This gives the students more track to work with. Helps...especially with the fans turned on. The old ones work better at 50 cm.

I made a few changes to the workbook and had the students change their copies. If you want to see my changes, email me and I'll send it to you.

I introduced the lesson after finishing lesson 3.3 today. We will start it first thing Monday. I have 4 tracks on counters and 4 on tables (that are pushed together). Wish me luck!

Lesson 3

3.1 and 3.2 worked most smoothly with 2 kids to a computer, if you have access to additional laptops. I added a box for explaining predictions above the graph in #7 and 10. I also asked students to get into the habit of labeling the axes of graphs like the computer printouts, both to make sure that they were differentiating between speed-time/position-time and because when I was working through #13 I found it much easier to have some units. Some kids had rationalizations like "The position graph is steeper when it is faster because it is going farther in a certain about of time." I asked all groups to show me their work when they got an initial idea for #13; I found many students misinterpreted this (because the actual question is above the graphs, not just where it actually says #13.), and just described the graphs instead of actually coming up with a rule that they could apply. They were able to do this well in the end, but it took a few check-ins. Rise over run came up frequently. I usually told students that was excellent, but also encouraged them to think about what rise would signify (what does it represent if it goes higher on the y-axis?).

I wonder if we could have a more clear-cut graph for #14 - I didn't see it causing problems with students, but when I did it it looks like it goes 100 m in 2 sec, or 50 m/s, while according to the data it is technically 40 m/s. This makes sense, because it just means my reading of the graph was off by 1/2 of a second, but it seems like if this is their first opportunity to check their strategy kids could think they've done it incorrectly. Probably not though - I haven't had that question come up yet.

Review/Debrief after 3.2

I decided to do a debrief/review after 3.2 to make sure everyone was understanding the concepts. I created a SmartBoard file to help. Let me know if you want a copy of it via email.

Watch for this in Lesson 2

Today at the end of Lesson 2, I started seeing that students' interpretations of the position-time graphs (and also their copying of the graphs from the Logger Pro application) was incomplete.

There were two ways they graphed these two graphs - I've drawn them crudely below:

The top graph is often interpreted by students as the red line is the faster motion and the black line is the slower motion rather than that they are both approximately traveling at the same constant speed. About half the class had a graph that looked like the top graph.

We agreed that the flat spots on the position-time graphs represented no motion, so then we just compared the first part of the motion for each of the two graphs that students reported.

I had a student collect and "store latest run" up in front of the class (projected on the SmartBoard) so that we could show the class the motion on the same graph. I then had students talk with their table group about which of the two graphs to the left best matched the data we collected up front. There was agreeement that the graph that best matched the motion up front was the second graph. Students were then instructed to make sure their understanding was written in their idea journal.

Also, watch for students who want to start these graphs at 0,0. That's not what the computer shows.

Lesson 3.1

This lesson goes very fast. Definitely can do it in one period. I handed back a bunch of papers and almost everyone still got through the entire lesson. I just have a few students that need to finish up the table tomorrow.

Lesson 2

This lesson went pretty well. I let the kids work on their own and it took two days. I had to help them with the graphs, though. They didn't understand that they had the position/time on the top one and the speed/time on the bottom one. They also didn't understand that they should have three lines on each graph.

I had colored pencils available for them for the graphs. It made it much easier.

I went around to each table for "check off" and discussed question #12. It seemed that each table understood the graphs, but could do better describing the lines in terms of "slope." Some groups that got confused, we discussed what a graph would look like if had a car going down the highway if we were going at a constant speed. That seemed to help, especially with the speed graph.

The shortcut CTRL+L didn't seem to work for some computers (?) but you could still use the drop down menu to save the latest run. FYI.

Elicitation Temptations

Ahhh, finally I resisted temptation during the elicitation presentations. Listening to student ideas and seeing what students have on their whiteboards and only asking questions without commentary is sooooo challenging!

Yesterday I succumbed to temptation and highlighted conflicts between what was said and written, and between two different representations of motion that came to different conclusions rather than making mental or physical notes to look for those conflicts after students have had lesson experiences on which they can build this understanding.

It's hard not to "teach" in the elicitation lessons, but to take on the role of listener and summarizer of the ideas that are presented. I also found that elicitation went more quickly when I didn't interject. In retrospect, I think this elicitation lesson can be done in two days.

At the end of the lesson, we summarized the two ideas about the position of the carts when they were traveling the same speed and summarized the variety of ways students expressed motion. This provided a bridge to the data collection tools we'll use tomorrow to gather motion data.

Most of the representations were only concerned with speed and very few explained this in terms of changing position and time. I think this will be something to watch for - since students calculated speed so much last year in last year's unit, there might not be conceptual grounding for an understanding of speed as something outside of a mathematical understanding. What I mean is that speed represents a change in position during a particular interval of time not just "distance divided by time". The latter will cause some confusion when there is changing direction (Part 2) or several intervals of time to consider.

Les. 1 Continued

So, the rest of my classes did not comment at all on the blue car slowing down. That seems to be in issue with one class only. But.... there is a consistent mistake on a graph representation. The kids are saying that the blue car is moving at a constant rate and so they are graphing it as a linear line, actually showing the car speeding up as time goes on at a constant rate. The graph is a speed/time graph, but they show the blue car increasing in speed even though they say differently. I am asking them about that, but they are not catching it so at the end of the presentations I will bring that to their attention. I would say this occurs with at least 5 of 7 groups. This really does take

Time and Elicitation - frustration

Yikes, elicitation lessons take time! It has been so tempting to pre-teach, draw students attention to something that they're going to learn, etc, in the elicitation and really delve deeply into student ideas. Tomorrow we'll power through the last couple of presentations so we can jump into Lesson 2. My goal for the next elicitation lesson will be two days (no longer) and perhaps I can ask my questions to groups as I am going around looking at their work.

Today, being a Weds, students worked on their boards for another 12 minutes before half the class presented. They did focus more on where and when the cars were at when they were traveling the same speed. Same two ideas are coming out - either the plunger car (blue car, in our case) was ahead of the fan car (red car) when they were traveling the same speed, or the two cars were at the same location when they were traveling the same speed. Sometimes these competing ideas were on the same board.

Another interesting observation: most groups that presented today are convinced that the plunger car slows down throughout it's path. Their explanations for this are gravity and friction. Makes sense based on their experiences, but not what they see in the lab. We made sure that our demonstration cart didn't visibly slow down throughout the trial. I tried to not pursue this one too heartily since those ideas will be further developed later in the unit. I did try to focus on the movement they could actually see (after the cart was launched and before it was stopped). I will try to not focus on this (the changing speed of the plunger cart) tomorrow, they'll have experiences with it soon enough.

MFE Lesson 1

After students have thought about the questions, run the cars and have the students look for when the cars are at the same place. Ask them if the cars are travelling at the speed. This will help them see that the constant speed car is "ahead" of the other car.

The question about when the cars are in "sync" helped them see when they had the same speed.

When they are making their whiteboards, they definitely need reminding that their representations need to show HOW each supports their answers to the questions. I didn't remind them and got some really random drawings. Whoops! When I did remind later period, there were much better diagrams!

I asked students to write their initial ideas to their Idea Journal question for #1 & #2 after we finished sharing.

Tracks

I found that to balance the tracks easily...put the feet at 60 and 160 and leave the "feet" alone.

MFE - Starting Lesson 1

Welcome to my reflections on teaching the Motion, Force and Energy unit. I asked Karen if I could teach one period a day to get an understanding of what this unit looks like (and feels like) to teach in a real 8th grade classroom.

We got the carts and tracks to work using the appropriate motion by with 500 g on the plunger cart and pushing the plunger in to the "2". For the fan cart, we put in three batteries and replaced the 4th with the aluminum cylinder.

Today we started with Lesson 1. I probably spent a little too much time showing kids the carts on the tracks. I thought they were going to get more excited about it - maybe it's just first period, maybe it's May, or maybe it's just that they weren't the ones handling the materials.

Students were able to describe that the plunger cart was traveling at constant speed and the fan cart was speeding up when I asked them to describe the motion in the large group; but later on in their smaller group discussions and on the representations on the whiteboards, they referred to the plunger cart as speeding up and slowing down.

Students were looking at the launch as speeding up and the "catcher" as slowing it down; so we had to redirect them to look after the launch and before the slowdown.

In order to get each student to respond when they thought the carts were traveling at the same speed, I asked them to raise their hands when they thought the carts were traveling the same speed. About half the class (maybe more) thought that the carts were traveling the same speed when they were at the same position on the track and another group thought the carts were traveling the same speed at a time when the fan cart was behind the plunger cart.

Students spent about 15 minutes writing their groups' ideas on the whiteboard, I hurried them along from their own representations (most had 2 or 3 representations before sharing) because I spent too much time on the introduction. I was glad to have several sets of whiteboards so they could return to them tomorrow.

I saw lots of graphs, tables, and a variety of pictures that represented the motions. One weakness I saw and will address tomorrow is how students use their representations to support the idea that there is a certain time or position where the two carts are traveling the same speed.