OK, maybe I’m in the minority, but I really like Back to School Nights. I appreciate the parents taking time out of their busy lives to come in and get a sense of who is teaching their students.

Tonight was no different. Great parents, lots of appreciation expressed, and a few good questions thrown in (not much time in ten minutes to ask questions).

Unfortunately, as usual, the higher academic classes have higher turnout of parents. Why? I can speculate about amount of free time, ability to get off work early, etc. But in the end, I don’t think it’s anyone’s fault (I suspect that all parents want their kids to be successful in school), it’s just a reality.

Thanks to all the parents who did make it out (and thanks to all those who didn’t for trusting your students in my care).

OK, I admit it: I can get sucked into the vacuum of social media and find myself having spent more time on it than I desire. Last December, with grades coming due, I decided to take a ‘vacation’ from Facebook. I’ve largely been off it for about seven weeks (I did jump on a few times to arrange my annual birthday dinner), and while there are things I miss (mostly family updates), I’m thinking of continuing my vacation, or maybe just checking in with some of my groups once a week.

But then there’s Twitter. I largely use Twitter for my professional development. I’m a teacher, and I follow many people/organizationsÂ that provide me with great tools to use in my classroom; and likewise I share many resources with those who follow me. But, how do I avoid getting sucked into this vacuum of learning–I can justify the time spent because the links I follow are mostly valuable.

Some tools I have used:

Set myself a time limit (and try to stick to it).

Ask myself “Do I really need to follow this link?”

Don’t feel bad if I decide to “Unfollow” someone.

What tools/tips do you use/have? Please share yours in the comments below.

Yesterday, I lead two short workshops on Modeling Instruction at the National Science Teachers Association area conference in Reno, Nevada. About 30 people attended the first one, and about 20 the second (about half of whom had been at the first one as well). As in many good physics activities, this included going outside (the floor in the conference room was carpeted, so the balls didn’t bounce well on it).

In the first workshop, I introduced the Bouncing Ball lab, which offers an introductory activity that focuses on developing students’ understanding of lab design and data analysis.

The second workshop introduced the Buggy Lab, that helps students develop a model for constant velocity motion.

Last blocks with buggies: Here’s another close up of the target sheets I use with my students. The complete the top, then find where on the row of four metersticks they need to place their prediction. I give not help at this point, and often ask “Are you sure it’s in the right place?” (even when it is). I try to involve all six to eight students in the trial (two combined groups of 3-4 each). When they are done, there is homework for them to work on in class.

A few tips:

Even with only four or five tests required (eight to ten groups), there is still down time for many students, so make sure you have something else for them to do. I always have that day’s worksheet/night’s homework ready for them. Next year, I plan to have something more in line with a conclusion on the lab.

My target has a very low “A” range, so, as I said yesterday, any group that lands on the paper gets an A.

Have them measure and calculate the speed of their buggy on the day of the collision test. This should take about five minutes, then ten minutes to make their prediction. If they use speeds from previous days, the batteries may have weakened and slowed the buggy down.

Use the “testing” time with your small groups to confirm they understand the placement of their paper. I often ask “Does this position make sense?”–to which they should answer “Yes, because the fast car will move a greater distance” or something along this line.

One train leaves a station at 2:30 at a speed of 40 m/s,
and a second train leaves another station at 50 m/s.
The stations are 40 km apart, and the trains are heading
toward each other. At what time and position will the
trains collide?

These days, many teachers use this as a chance for an actual experiment. I challenge my students to determine the speed of their cars, then I match them up with a random group (well I know each group has a car with a different speed). They then need to calculate the position the cars will collide if they start four meters apart. I have a grade sheet that shows them their grade. My standard sheet has A-D on it, with A at the center where the cars are due to collide.

With each buggies traveling 1.2-3.8 meters, I probably should give them a bit more slack in the “A” range, so I’m thinking that for next year I may use three sheets of paper with most of the center one being the “A”, and the outside ones being B-D.

I like this lab because it’s easy to get correct predictions, and students have to go back and check their math if they don’t get an “A”.

Here’s a video showing an accurate prediction. The class, and I, get quite excited as the collision moment approaches!

OK, I’m cheating a bit, but I do teach the same classes on Thursday/Friday this week.

I triedÂ a new technique this year for introducing motion maps. I stood at the board and asked a student to call off every second. I started a car moving at the base of the boards (my new classroom has floor-to-ceiling whiteboards), then draw a mark at the location of the car each time the student called out a second. Asked students what the dots told them, and they replied that since they are the same distance apart, the car is going at a constant velocity (yay!!!).

Next, I put the same car at the right side of the board and, with my student calling time, marked the position of the car going in the opposite direction. Asked class what the dots tell us–and they said it’s going at the same speed.

Then I asked ‘what’s missing’ from the diagram, and, with some false starts, they decided that direction was missing. ‘How could we identify direction?’ ‘Arrows!’ they answer. So, I add arrows to the drawings.

Next I bring produce a faster car, and mark it off.

'What's the difference?'
'It's moving faster!'
'How do you know?'
'The arrows are further apart!'

Wow, almost there.

Finally, I take place a 2’x3′ whiteboard perpendicular to the wall (classroom has small slots between vertical panels that are just perfect to hold these whiteboards) and start a car towards it. These “Tumble Buggies” are designed so when they reach a wall they flip over and start in the reverse direction. While I’m marking the on the board, the car takes 2-3 seconds to flip, and I have a few marks on top of each other (I purposely put them not quite on top).

'How long did the car not move forward or backwards?
'Three seconds.'
'How would you show a dot for an object that is not moving?'
'Huh?'
'How would you show a car with a very slow speed?'
'A very short arrow.'
'So, how would you represent an object that is not moving?
'A dot with no arrow!'

I then ask them what the graph of these would look like, and we draw it on the board, starting with the first car and soliciting questions after each graph.

Finally,Â I ask students to describe the motion of each car in words.

'A is moving forward slowly.'
'B is moving backwards at the same speed.'
'C is moving faster.'
'I what direction?'
'Forward!'
'D moved forward slowly, stopped for a few seconds, then returned to where it started.'

After this, it’s off to the “Motion Maps and Position vs. Time Graphs” worksheet (I also have my revised version of the traditional Modeling Instruction motion map reading online for them as a back up).

“Notes for next time”

I think I’ll roll one of my tables up against the wall, to make it easier for all students to see. Someone Tweeted about a “Fridge Rover” can that can roll on metal vertical surfaces, but I find having the car able to turn around more important that having it roll on the wall đź™‚

I’m a big one on looking at large quantities of data. In each of my physics classes, I have seven to nine groups. In the Buggy Lab, that provides enough data that whiteboard sessions go fairly well, with:

at 3-4 groups going in each direction

two groups starting at extreme positive or negative locations

three to four starting at medium locations

two groups starting at zero

three to five slow cars and three to five fast cars.

But that’s not enough for me đź™‚

I have my students submit their calculated results to a Google spreadsheet, so we end up with around 30 different sets of results. When we have our whiteboard meetings, I’ll have the spreadsheet available if students want to look at more data (and, of course, I hint that this would be a good idea).

Here are some results from this year (homework is to complete it, so not everyone has posted yet). I use Format…Conditional formatting… rules to add color based on the values.

This year I’m having my students use shared Google docs for their lab write ups (developing their procedures, recording their data, etc.). One student starts the document and shares it with the others, so everyone is working on the same document.The problem with Google Docs is most of us can’t draw on a computer (while touch screen devices may offer some help, it’s generally not as good as what we can do by hand, and/or takes more time).

My solution for creating better images: Mini-whiteboards and photos with their phones.

Students can work together on a their whiteboard, and everyone can see it, regardless of the angle. When they are happy with their drawing, they take a photo of it and add that to their document.

We’ll see how it goes, but I like the results so far. I didn’t get any images of complete images, but here’s one that some students started on (yes, I believe that’s a mushroom cloud where the cars collide):

There has been debate in the Modeling Instruction community over how to handle “summaries” at the end of labs/units. We like summaries because they provide our students a place to go to see conclusions that are agreed to as a class–but we worry about them because students may not be as engaged in the labs/discussions if they know the “answers” will be posted at the end.

Such is the life of a teacher đź™‚

This year, I decided to try a summary after each unit. At the end of the unit, I will project one student’s screen and s/he will type in the words the class agrees on. I’m starting with more involvement, but hope to remove myself from the discussion as we progress through the year. I am using Schoology’s Discussion feature, students who aren’t clear on the summary can always post questions (and, hopefully, responses!) later.

We just finished our intro unit, the goal of which is to introduce students to plotting data and making predictions from those plots. Here is the conclusion from one period today: