Wednesday, April 28, 2010

Pizza Party!

I thought about giving this to my 7th graders...

Monday's Math Problem via @NCTM:
Batman and Robin each order a pizza. The circumference of Batman's pizza is 20 percent greater than the circumference of Robin's pizza.The area of Batman's pizza is what percentage greater than the area of Robin's pizza?
...for about two seconds.

But instead, I gave this:


What We Did

1.  Decided that the best question was:  Which pizza is a better deal?

2.  Misconception:  Comparing diameters to determine which pizza is preferable.  This leads to believing that two personal pizzas are a better deal than one large. (Note to self:  Let them think this as long as you can.  It's kinda fun and the truth hits them harder if they're committed to their initial opinion. )

3. Realized that area is the way we measure which one gives us the most pizza.

4. Determine area of each pizza and calculate $/sq".

5.  Sidebar:  Is $/sq" or sq"/$ a better rate to use?  Let them decide, but make them justify. 

6.  Extension: What are we really paying for?   Not the crust.  Assuming that the average pizza contains about 1" of crust on the circumference, removing it takes the personal pizza from $.14/sq." to $.28/sq".

7. Synthesis:  We brought out the laptops and put our data into Excel.  I allowed them to enter the diameter and cost for each pizza then showed them how to use the function and fill features to have the program do the number crunching for them.  I'm actually disappointed with myself for not doing this earlier in the year.  I often forget how powerful Excel is for teaching math. 

8. Conclusion: If you order a personal pizza, eat your crust!


9. Reflection  I wasn't prepared to handle the question on rates.  I think in terms of $/sq" and assumed that my students would too.  I also took an opportunity for student ownership away by drawing the two 7" pizzas inside of the 14" instead of allowing the student who came up with the idea a chance to shine. 

I'm taking this one on the road and will swap classes with other teachers in my department to see how their kids handle it. 

10.  What else would you have done with this lesson?

Tuesday, April 27, 2010

Put Some Pants On!


I feel like this quite often.  And I received a tweet from @mrhodotnet with this TED talk by Barry Schwartz on the Paradox of Choice.    There are a couple of references in this talk that will keep me from showing it in its entirety to my classes, but there was one story that really struck me.  One that I had to share with my classes. 

Schwartz talks about a time when he has to buy a pair of jeans.  The last time he had done this was when there was one type of jeans that fit horribly until they had been washed a few dozen times (anyone remember Levi's 501's?).  When asked what kind of jeans he wanted this time, he replies, "I want the kind that used to be the only kind."  The clerk being clueless as to what this meant proceeds to show him his options.  After about an hour of trying things on, Schwartz settles on the most comfortable pair of jeans he had ever worn. 

But here's the kicker--he says he did better but felt worse.  He had purchased the most comfortable pair of jeans he has ever owned yet felt worse about the experience.  Why?  Because maybe he left the best jeans in the store. 

I think our students experience daily.

What do you think?
"I dunno."

What step comes first?
"I dunno."

What is the rate of change in this equation?
"I dunno."

I'm convinced that these I dunno's are a result of our student being afraid of leaving the best answer unspoken and find it safer to stay neutral. 

To which I say:

Quit standing there in you underwear and put some pants on.  Don't worry about finding the best pair.  Pick one.  Don't worry, they'll break in. 

I think I'll get a little mileage out of this metaphor. 

Monday, April 26, 2010

WCYDWT: Oranges

Oranges are packed and sold using a standard box...



 and contain fruit that is all the same size (kinda) based on average diameter...

which is determined using this:

They come in 10 sizes: 36, 40, 48, 56, 72, 88, 113, 138, 163 and 180 which is based on the number of pieces of fruit that can be packed in the box. 




No Disruptions



I wonder what would happen if we showed the same respect for instructional time.

Thursday, April 22, 2010

Standard Deviation

For those of you who have been reading a while, you know that I'm not the best lesson planner in the world.  My SmartBoard slides aren't always the best designed, although that's something I'd like to improve upon.  And I'm not that creative with activities.  But today, I realized that I'm pretty good at getting out of the way when some real inquiry shows up. 

My 7th graders just finished state testing yesterday and I wanted to help set the stage for what I'm going to expect from them next year as 8th graders.  The 7th grade curriculum is not much different than grades 2-6; it's very skill based.  My kids are very good duplicators, but I want them to become good applicators and eventually creators.  I explicitly said that to them today.  I want them to focus on representing their ideas as many ways as they can. 

Tom Henderson:
@mathpunk

Anyway, the theory goes that you don’t understand a mathematical concept until you understand it in TWO modalities. I do very well with visual knowledge, so my notes of understanding are full of color and pictures and mindmaps and arrows linking concepts, and I highlight the holy hell out of math books. However, I don’t believe I KNOW a concept until I can explain it verbally, because I can barely understand anything if someone just talks it at me.

First swipe is through my best modality, second swipe is through my worst modality. The whole “learning style” thing may be overstated, but it remains true that getting students to understand things in a variety of modalities seems like the way to go.

So today the plan was to:
  • Have a little chat re: expectations
  • Work through some pattern recognition via sequences
  • See if I can get them to describe the patterns at least two ways
  • Do an activity with algebra tiles
 Chat went well.  And I showed this slide:
Note: I'm pretty sure you get sequences 1 and 2, but just in case, sequence 3 has to do with words. The first term has one one (11), the second term as two ones (21) and so on.  So n5 = 111221.

Kids are really good at finding the next numbers but pretty lazy about writing a good description of the rule.  The had to add, "for example" to many of their written rules.  The challenge was to have them write a rule that was short but stood alone.  The got it. 

Challenge:  Can we write a rule in Mathanese?
I explained subscripts and how they can be used to name different values for the same variable.  For example: n5 represents the 5th term in the sequence. It didn't take long for them to recognize that:
n5 = n4 + n3

"So, if n5 = n4 + n3, what does nk equal?"

"nk = nj + ni."

This led to a great discussion on how the alphabet doesn't nec-ess-a-ri-ly have one to one correspondence with the whole numbers.  Good talk nonetheless. 

We ultimately settle on nk = nk-1 + nk-2 and for the most part the class was good with that.

Sequence three provoked something I hadn't considered before.  Luke asked if the fifth term could be 1231 or even 3112.  He explained:

"Each of the previous terms are describing what comes before it, but does it have to be as you read it left to right? Could it just be describing the amount of times the digit shows up in the term."

"So if I would have given you the fifth term, would your rule work?"

"Nope."

Then Joe comes out of nowhere.

"Are there more possible right answers?"

This is just too good to be true.  We now have two questions we need answered:
I let them choose which question interested them the most and split the class into two groups to investigate.  Group one came awful close to saying that nk = nk-1 + k - 1. They're not quite there so I'll let that one marinate for the night. Group two came to the conclusion that there were no other possible 5th terms. They were a bit disappointed because they thought that they got the wrong answer.

"No, no, no. You had a question. You investigated it. And you decided that the answer was no. Can you explain why the answer is no?"

"Yeah."

"Then that's a good day's work."



Gonna have to finish the algebra tiles tomorrow.

Wednesday, April 21, 2010

False Dichotomies

Do you grade formative assessments or not?

Is it inquiry or an investigation?

GeoGebra or Sketchpad?

Paper of plastic?

Why does it have to be either/or?  I don't care.  Just bag my groceries so I can go to my car.  And hurry up before that guy with the clipboard and stopwatch comes and starts asking questions. 

Taxonomy

In the age of accountability, we have become increasingly skill based. That's not necessarily a bad thing. But I've noticed that with each benchmark, common formative assessment or state test we give, teachers have the tendency to focus on the product and not on the process (ie. let's give them the skills and pass 'em down the hall). I encourage inquiry with my students. I allow them to fall down the rabbit holes we encounter. In fact, I've been known to scrap the lesson for the benefit of a good question a student has asked. Most of us do. But the one thing that I've noticed as well is that even my grades have become increasingly skill based. I've been wondering how to assess the problem solving stuff. A colleague clarified some of this for me the other day at lunch. We were discussing the idea that once a student has been shown how to work a problem, it then becomes an exercise and no longer carries with it the attributes that allow a student to be a problem solver. He shared with me that he noticed how his students would ask for an example every time he tried to get them to do some problem solving and how that just didn't sit right with him. It doesn't sit right because the student is trying to take a problem and apply the teacher's algorithm to it. If the example is close enough, he can plug and chug, get an answer and we'll be none the wiser.
If we can get our kids to be proficient with the skills, show the ability to put them together in a problem solving situation and occasionally surprise the pants off of us with one of those "wow-look-what-you-did" moments, I'd say we'd call it a good year. This continuum can be tricky, though. The more time a student spends wrestling with the skills, the more time we need to be there for support. As a student becomes proficient with the skills, we can let go a little more and become a facilitator. I think that many teachers get frustrated because they hear of these great things that are going on in the classrooms of others and wonder why it won't work in their room. Well, maybe it will. But maybe it's because we've put the kid on a mountain bike before he can ride the tricycle. Can't expect a kid who is buried in skill acquisition to blow the doors off you with his inquiry methods--which isn't to say that the student doesn't have the ability to inquire, it may just need some dusting off.

At the end of the year, I'd like my students to be able to duplicate skills, apply skills and create something using the skills.


Duplication aka: Skills

Description: Here's the tool. Here's how you use the tool. Show me you know how to use the tool. Do it again, I don't believe you. One more time, just to be sure. Alright, you are now allowed to use this tool whenever you see fit.

Essential question: Can you use the tool?

How: How these skills are taught may vary. Direct instruction, investigations, Socratic method...I don't care. At the end of the day, the student is acquiring a skill. The more of the lifting they can do themselves while acquiring these skills the better because they are preparing themselves for the next steps of application and creation. Asking questions is going to be the teacher's best friend.

Assessment: Skills tests in the form of multiple choice or free response. Students are free to reassess at any time during the year as their understanding of the skill changes. This is why I don't have a problem with posting study guides and online examples. There are no surprises on my skills tests. Each different skill corresponds to a different assignment in the gradebook. I'm not really too concerned with how they arrive at the answer as the focus is on the product.

We don't give finals in our middle school, but next year I am going to give a summative test every 6 weeks or so that cover all skills to date. For example, the first assessment will cover skills 1-8, the next will cover skills 1-19, and we will end with a cumulative skills test covering skills 1-39.

Application aka: Problem Solving

Description: I want you now to build something. Choose which tools you will use. Make sure your final product looks like *this*.

Essential question: Can you put more than one tool together to do something you haven't done before?

How: Give students a problem that uses skills they already have and walk away--sometimes literally. In this process, I think the students should generate more of the questions--although prodding them along with a question now and then isn't a bad thing. Be careful though, I have found that sometimes I have to take a physical posture of audience member by actually sitting down and looking at the floor in order to cease being the primary resource.

Assessment: This can be in the form of a teacher created project, short assessments requiring students to demonstrate their thinking or even an observation during class. I've thought about including higher level problems in my skills tests and students who successfully solve the problems earn a 5, but then I run into the problem of reassessment and context. The skills test will often give a context to the problem that we may not want the student to have. Reassessment on this will be different because it isn't about the particular problem, but the process by which the student attacks the problem. I'd argue that the skills necessary are irrelevant as long as the students being assessed possess the skills necessary to solve the problem. If this is a written test, it should contain problems the students have never seen before. So I'm thinking about a "Problem solving" weighted category or maybe a weighted standard that is dynamic the same way the other standards are.

Creation aka: Projects

Description: Now, what would you like to build? Design it. Plan it. Build it. Reflect on what you built. Did you choose the right tools? What would you do differently next time?

Essential question: Do you understand your set of tools well enough to recognize what types of things you can and can't do?

How: Student generated projects. My 7th graders are working on a relations project where they choose two variables to compare, gather data and investigate the relationship. Final product will include multiple representations of their data and a presentation using the medium of their choice. (I'll blog about it after we finish state testing.) I really like what Shawn Cornally is doing with his physics kids. If anyone can help me figure out how to do this with some precocious middle school math students, write a book and I'll buy it.

Assessment: The project is the assessment.

Creation > Application > Duplication

Success in any of the higher levels validates the lower levels. For example: If a student can demonstrate problem solving ability by writing an equation and solving it, then not only does this affect the problem solving score, but it validates the equation solving skill. If a student can create her own project, then I'd say problem solving looks pretty strong as do any skills that were present in the project.

The Book
The worst part of all this is that we gotta give it a grade. How do we arrive at a final mark? This year, I left my grades uncalculated until the marking period opened and once grades were submitted, they went back to being uncalculated. I wanted parents and students to focus on the score for each skill and not the "averages." To arrive at a final mark for the students, we look at our rubric the same way one would view a grade point average.

4.5-5.0 = A
4.0-4.4 = B
3.0-3.9 = C
2.0-2.0 = D
< 2.0 = F

This was simple because there were no weighted categories. But now with the fact I want to focus on problem solving, projects and include summative tests, I need to figure out how this should look in the grade book.

Questions

  • Where does problem solving show up in your gradebook?

  • Should the scores on the summative tests have their own category in the gradebook or should each skill be treated like it's own reassessment?

  • Have I lost my mind?