“Why do you have us do things that aren’t for a grade?”

This question was recently asked of me by a student when I was collecting warm up sheets for the week. I do not grade their warm up sheets, but I do respond to every Free-Write Friday and usually comment on another day’s warm up. I would never stop doing this because it has been amazing how much I have learned about my students through the warm up sheets. 

I don’t know if my response was a good one. All I could think of in the moment was, “These help you think more mathematically, and I collect them to know more about you and so you can get feedback from me.” I also could have talked about how their grade, in my opinion, should be a reflection of their math knowledge, so grading things like warm ups and practice for completion wouldn’t be good feedback in their grade.  

Sometimes I have a hard time motivating my students, especially the new ones, to do classwork when it’s not for a grade. Some of them say that I’m the only teacher they have that doesn’t put a grade on everything they do. I know that at least some of the other math teachers don’t grade everything because I’ve asked them, though. I think students sometimes feel that they need some sort of reward for their efforts. I say that their efforts will show when they take their assessment. I think some of them need some time to adjust to that. 

Do you grade everything? What would you have said to my student?

Une question difficile. 

Similar Triangle Building (Not a Good Activity)

I’m posting about this activity that wasn’t really a good activity (some may even say it was bad) because maybe someone can use it and make it better.

I’m teaching a similarity unit that is very boring. Ratios/Proportions, Similar Polygons, Proving Triangles Similar, and Proportions in Triangles. No mention of transformations, no scale factor, no area/volume…and on top of that my students have never seen anything about congruent polygons. So I was looking back at my old geometry files (yay for finally teaching something I’ve taught before!) and I adjusted my notes packet and printed that for the kids. They love that their notes are all in a packet. But every day was just notes and practice, notes and practice, notes and practice. I was so bored. Kids were bored (truth: some were probably thinking this is normal). So I remembered my old activity where students discovered the triangle congruence theorems and thought I could possibly make that activity work for similarity.

It didn’t really work…Here were the problems:

  • Building the triangles takes sooooooo long. I wish I had read my old post more carefully and believed that it would take so long. I cut it down to 4 triangles and had groups of 3-4 and it still took about 35 min just to build all the triangles. Why does it take so long?
  • I didn’t have a lot of color paper to use so it was hard to see the cutouts on the board.
  • I had two different groups so there should have been proportional sides. I only told that to my last period for some reason, so the other periods didn’t really get why triangles were similar
  • It’s a lot easier to see that triangles are the same than see they are similar – you just kind of have to guess and a lot of them didn’t trust their intuition that we could rotate and dilate (probably because it wasn’t ever discussed)
  • Once one triangle was put up for my SSA example, the other groups would just make the same one that they saw so some classes ended up thinking SSA made similar triangles

IF I was to do this again (which I don’t think I will), I would:

  • Not have students put up their triangles until the very end
  • Demo building the triangle (only thought of this in my last class)
  • Use color paper
  • (Maybe) ask kids to specifically check for similarity – congruent corresponding angles and proportional corresponding sides. This takes some away from the discovery but would make it less of a guessing game. It would also take more time.
  • Plan for it to take a lot of time

Here’s the files just in case they’re useful to someone:

Similar Triangles Discovery.docx      Similar Triangles Discovery.pdf

N’enseigne pas cette leçon sauf si vous le modifiez.

Barbie Bungee

This was in my drafts since Decemberish 2015. I am posting it so I can go back to it if I’m ever teaching linear regression again:

I did Barbie Bungee this year [Fall 2015] with two of my classes – Algebra II and College Algebra. I got the activity from all the other people who have posted about it. Seriously, just go to the MTBoS Search Engine and search for “Barbie Bungee” and there are multiple pages. At this point, I don’t remember who I took most of the activity from. I think it was either Fawn or Matt.

I gave students 2 90-min blocks to work. They were grouped randomly in my Algebra II classes and I let them chose groups in my College Algebra class.

This was the worksheet that students used: Barbie-Bungee

Barbie Bungee Quotes (all from students):

  • Did you mark 0? No – 0 is her initial height
  • What’s the height it needs to be at? 2.92? That’s like 292 cm!
  • You guys can use our rulers on the wall – just subtract 20 from your number
  • Wow you guys were really precise! We need to do ours over.
  • I thought I just broke Ken’s nose
  • Ken is way heavier, so it makes sense we need less than them (group with Barbie)
  • Wait but she goes lower than where she ends up at the end – we have to do it again!
  • We can’t just guess! This is Ken’s life we’re talking about!
  • I don’t know she just like had a seizure or something and fell!
  • It keeps hitting my arm – hold it a little bit away from the stick so it doesn’t hit.
  • I’m at 85 now, so whatever that is plus a meter. No! A meter minus 85 plus a meter.
  • Should we redo these two? I feel like they’re way off and will throw off our data.
  • Come on get low so you can really see where he goes!
  • Wait if we plug in 2.92 that’s not in cm.

Pictures of the work process:

The activity also came up in a few of the students’ end-of-semester reflections for their portfolios! I love some of the comments that the students had about collaboration and responsibility.

Videos – were played at a very slow speed to break ties in a couple classes and also to determine if one hit the ground or not. These are the ones that don’t have a student’s face in it. Taken by a student with my iPad:



Mes étudiants précédents me manquent.