Distance Formula without the Formula

Today in MPM2D our main goal was to discover how to find the distance between two points. But since I’m spiralling the 2D course I wanted to think big picture…I  wanted to tackle this overall expectation: verify geometric properties of triangles using analytic geometry.

We started with this beauty from Would You Rather  — www.wyrmath.wordpress.com

Students argued and discussed which ramp they would rather push that crate up. Most of the class picked A with their reason being it’s less steep and less work. One of the students who picked B said “I want muscles…..so I’m going to push that crate up the steepest slope“. Another student picked B because they wanted less distance and wanted to “get it over with“.

I left the discussion hanging here knowing I was going to come back and revisit this with more ammunition.

I showed them this video

and we completed the Corner to Corner problem (see the lesson plan here) to remind ourselves of the Pythagorean Theorem.

We came back to the Would You Rather problem from above and practiced finding the length of each hypotenuse to see how long each was.

I then presented them with this……and said our goal was to find the length of this line segment.

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Find the length of this line segment

I asked…”If I could help you out or provide you with more info what would you want?” Most students said they would want either a ruler or some sort of dimensions or units to look at.

So I  brought up the grid on Desmos and asked if this was enough.

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Most students thought it was…..I could see them drawing right triangles on their whiteboards and filling in the lengths of the legs. But one students yelled out “What is the scale?” ….Everyone paused! ….. I brought up the axis!

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Students finished drawing their right triangles and said that was easy! We did one more just like this (giving them the grid and axis) to practice.

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Here’s the next challenge: I took away the grid but gave them the coordinates of the endpoints. Find the length of this line segment.

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I let them struggle a bit here. The majority of the class prevailed and had a similar solution on take up:

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Student words: “One leg was the difference between the x-values and the other leg was the difference between the y-values”

We did another in the same format to practice this discovery.

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Then I took it up a notch…

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The three points shown represent vertices of a triangle. Classify the type of triangle.

And I saw a lot of this…

 

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I’ve been following Mary Bourassa’s Blog and I stole creating my own homework sets from her….so I left the class to complete this. Love how I can ask lagging questions in my homework. Students get multiple opportunities to master skills.

So we’ll take up those questions tomorrow and we’ll summarize the strategy to find the length of a line segment using this formula…daum_equation_1443477587316

Access: Pre-made Desmos graphs

 

Lollipop Lollipop oh la la Lollipop! — & Rates of Change

Last year on twitter I saw that Alex Overwijk and Janice Bernstein with their grade 12 advanced functions classes did this lollipop activity!

I knew that I wanted to give this a try for this semester! What I especially love about this activity other than students experiencing rates of change is that this is an activity that can span multi-grades!

Here is what we did,

Generating Curiosity

I found this video on YouTube and asked the class to think of great questions we could ask about what we see!

FullSizeRender-1Great questions from the kids and we all agreed to look at

  • How does the sucking time affect the radius, circumference, volume, and surface area?
  • How long will it take until the lollipop is all gone?

Let’s investigate those relationships starting with the easy to measure (circumference) and also estimate how long it will take until the lollipop is no more!

We had guesses : ranging from 10 minutes through to 35 minutes.

Gathering Data

I handed out one lollipop per pair of students, along with some dental floss for measuring circumference. We set our timer for 30 seconds and began sucking and capturing data!
We recorded the circumference every 30 seconds up to 7 minutes like Al’s and Janice’s instruct in their lesson Plan.
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They also have a great handout for tracking the circumference over the 30 second intervals. Screen Shot 2015-09-18 at 2.22.08 PM

Analyzing the Data

So we first looked at the Time vs. Circumference and Time vs. Radius relationship
Linear - Lollipop

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We discussed its linearity and why. Students predicted with more accuracy when their lollipop would run out.
Up to this point this task is great for grades 7, 8, 9, or 10!! (Just edit the file to exclude the average and instantaneous rates of change).

  • Grade 7 & 8: Practice plotting points and reading/interpreting graphs.
  • Grade 9 & 10: Find lines of best fit and first differences.

We found the average rate of change for each 30 second interval and discussed what this meant. We used the last column to talk about narrowing the interval down to estimate the instantaneous rate of change, and noticed that it’s about the same for all values. Why does this make sense???

7Yar2VXD

 

We moved on to looking at Time vs. Volume and Time vs. Surface Area

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Great talks around how Volume and Surface aren’t deceasing at a constant rate! It changes! Students can see these changes and see in their tables where the volume is changing the fastest.

Overall a great intro activity to get students thinking about narrowing intervals to approximate instantaneous rates of change.

Next up: We’ll relate what we did here with the tables to the graphical interpretation of rates of change (secant and tangent lines) and then on to the algebraic!

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R2D2 – Pear Deck/Desmos Mash Up!

School is just right around the corner for us up here in Ontario and I can’t stop thinking about that first day. As for my grade 9 applied class’ first day I have ran the R2D2 problem in the past with great success.
Now, over the summer I’ve seen great improvements in Pear Deck and wanted to get into it! Also Desmos has been busy and released Activity Builder!! So let’s mash these two apps up with some R2D2!!

So here is the R2D2 problem presented with Pear Deck and an extensions with Desmos….

Act 1: The video

and this is what Pear Deck will show after you insert the video…..love how the video will be displayed on the projector and not on each individual device!!!

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I like using Pear Deck here for asking for wonderings and notices because it allows students who normally won’t shout out answers to have a voice in the room. Students get to input their responses and the teacher can show them on the projector.

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For generating estimates I absolutely love how they put our Too high and Too low guess on a number line…..it gives us the visual of where our actual estimates will lie.

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Act 2: Gathering the Info

In the new version here I get students to draw their estimates of the dimensions of both the board and the post it note…..this pushes them into drawing diagrams.

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Revealing the dimensions….

 

Students are ready to solve….

 

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Act 3: Revealing The answer

The Extension: How many rectangles can we make that have an area of 609 post it notes?
To extend I want students draw out different rectangles and label their dimensions! They can use Pear Deck’s white board!

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But then they can enter them into Desmos through a pre-made activity I created in Activity Builder. (the Pear Deck file links to the Desmos activity).

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For each rectangle the student can come up with they find the perimeter and plot the length vs. perimeter in the Desmos graph. The teacher on the projector can use the Overlay function and show all the different rectangles students are coming up with…essentially showing the pattern that emerges! Using the pattern students can read off the minimum perimeter!

 

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If you have a Pear Deck account Grab and download the file below!

[aio_button align=”center” animation=”none” color=”blue” size=”medium” icon=”star” text=”Pear Deck File” relationship=”dofollow” url=”https://drive.google.com/file/d/0B9g0jeaVwshveDVhWktzdTRudE0/view?usp=sharing”]

Link to the Desmos Activity

Teach Math with Spiralled 3-Act Tasks – a full course

This semester was my first go at spiralling a course through problems instead of units. Traditionally we teachers follow the chapters and sections from the textbook. Well why not? It’s all laid out and organized nicely….most times in 1 day chunks….no planning needed, am I right???

How exciting is it though? How much do students really need to think? Are they really solving problems and learning mathematics.

After reading about spiralling from Alex Overwijk and bouncing ideas back and forth with Kyle Pearce we decided to give spiralling 1P math with 3 act tasks a try.

Each day or two I would  introduce to a new 3-act math problem (read Teaching with 3-Act Tasks) to solve with students. We would use that to stimulate wonderings and finally narrow down to a particular goals I wanted to cover.  Each of these lessons is taught with a 4 part math lesson (From Kyle Pearce) which always has students working on solving problems on their own FIRST, and then we step in and teach skills (“math teachery” way) after.

We did not teach within units. We mixed up our 3-Act tasks and problems throughout the semester.

I kept a list of all lessons, and order I used, along with any resources like blog posts, video files, handouts, etc. I wanted to share that list below.

Access the sheet Now
Spreadsheet design was by Kyle

The spreadsheet shows for each day,

  • the strand we covered,
  • the learning goal (LG – for my assessment sheet),
  • the topic, notes for planning,
  • the inquiry lesson portion (3-Act math problem(s))
  • connections to other strands (a place for me to remind myself to tie this piece to other strands)
  • the consolidation/practice resources/links
  • other resources like blog posts, handouts, links, tweets, etc.

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You may notice the bright pink row. These are our assessment/mastery days. We had one whole class each week for this.

The first half of an assessment/mastery day class was handing back of past paper assessments that look like:

Assessment

Each one consisted of 4 questions that covered the learning outcomes of the last week or so.  I wrote feedback for any question that weren’t completed perfectly. They were to read the feedback and re-do those questions.

I let them know that everything counts…..I consider all our conversations, my observations and anything they hand in for their grade.

Also during the first half of class students worked towards upgrading their skills. They access their customized spreadsheet which shows their achievement on each of the learning goals. They choose a learning goal to upgrade. Based on their prior achievement they are given another task to try. After I assess this new task I go and change the mark for that learning goal.

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Both Kyle and I have written posts on this sheet a few times. (here, here, and here). An idea we extended from Alice Keeler.

We spend a good chunk of time working at getting better on our skills always promoting growth!

The last half of the class we do this week’s paper assessment (that looks like the one above). I mark it and give it back so that next Tuesday we can do that all over again.

Here are some benefits I have noticed from both spiralling and teaching through problem solving:

  • Almost no need to review at the end of the year. We reviewed all through.
  • Students see how math connects together. (Proportional reasoning shouldn’t stand as a lone unit when you have linear relations and algebra to teach too!).
  • Students were more confident in math than I’ve ever seen them. (And for 1P’s too!). When teaching in units, students know that whatever problem we will solve today HAS to do with what we learned yesterday. When we teach through spiralling students are always wondering what math they can use to solve the problem at hand. My students became great at risk taking! They would try! How many times has it been where we give a new problem to our students they complain that you haven’t shown them how to do this. My students were given new problems everyday and they became great a trying strategies. Whiteboards help immensely with this too!
  • A time saver! You may think that I would run out of time teaching this way…..I couldn’t possibly teach through problem solving and still cover everything, let alone booking a whole day dedicated to growth EACH WEEK! We had lots of time. Since each lesson tied multiple expectations and learning goals together, we could cover more in one lesson than we could in two lessons the old way. The growth/upgrades each week allowed students to practice skills from all over the course. Around mid-term time I gave my students an old final exam to see how they would do, and they did great!!! I was amazed. We still had half a semester to go!

Since we are coming close to the end I wanted to share my experience! Feel free to check out my daily plan from grade 9 applied

Access Now

As always, if you have any recommendations or feedback for me I would love to hear about it!