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.