Math Links for Week Ending Dec. 5, 2014

If you have a couple of hours to kill and want to think deeply about fractions then I suggest this Adobe connect from Dr. Cathy Bruce. Dealing with the conceptual ideas that relate to fractions.
Curriculum Tags: Gr7, Gr8
http://learnteachlead.ca/projects/mathematics-web-conference-hosted-dr-cathy-bruce-teaching-fractions-whats-big-deal/

I have really been pumping out the Geometer's Sketchpad files lately. This latest one is meant for students to practice estimating square roots (without a calculator). The are four levels of guessing: Perfect squares under 100, Perfect squares under 500 (both appropriate for grade 7) Square roots under 100, and Square roots under 500. These last two require students to estimate the square root of non perfect squares without a calculator. The software generates all the random numbers and students can check their own answers. And as always this works really well with the Sketchpad Explorer app on the iPad.
Curriculum Tags: Gr7, Gr8
http://engaging-math.blogspot.ca/2014/12/geometers-sketchpad-square-root-number.html

I like this post because it does a good job of taking something that we normally do and then giving it a little tweak to make it better. In this case it is in reference to all the distance time graphs and the tweak is to add a notice/wonder step at the beginning where students are asked no specific questions except what they notice and wonder. It's actually a good thing to consider when looking at any graph. As a bonus the worksheet downloads are included.
Curriculum Tags: Gr7, Gr8, MPM1D, MFM1P, MFM2P
http://drawingonmath.blogspot.ca/2014/11/distance-graph.html

I have often said that sometimes all you need is a little tweak to get students to do something they normally were reluctant to. Here is an example. In both Grade 12 Advanced Functions and Calculus and vectors, we have to be able to describe functions and curve sketch. This tweak basically has students write personal adds for functions to describe them. Couple that with Desmos or GSP and you now have made that dynamic. Here's an example

I am a very negative and odd function. I have been working my way from quadrant 2 to quadrant 4. I have no curvy parts and I like to rest right at the origin. I am looking for a function to put a little more life in me. Two turning points is a must. I'm, looking for a positive influence in my life. 

For more examples and some teaching suggestions, check out the post at the link below
Curriculum Tags: MHF4U, MCV4U
http://musingmathematically.blogspot.ca/2014/11/polynomial-personal-ads.html

I am a big fan of using portable white boards in class. Years ago we used to go to the local hardware store and by 4'x8' sheets of tile board then have them cut them into 1'x1' pieces. But it never occurred to me to cut them in larger size pieces for group work. That is just what Andrew Stadel did and even came up with some suggested uses. Check them out here.
Curriculum Tags: All
http://mr-stadel.blogspot.ca/2014/12/large-whiteboards-get-em.html

These types of questions are fun to work on in math classes, especially if you dissect it to figure out how it works. These are great when introducing the idea of algebra to students. Hammer out a bunch of examples then introduce the idea of a variable instead.
Curriculum Tags: Gr7, Gr8
http://www.realclearscience.com/blog/2014/10/the_math_behind_the_shoe_size-age_trick_108920.html

Math with Bad Drawings is having some fun with Trig on this post. Make sure you go to the link to see all of the different drawings
Curriculum Tags: MFM2P, MPM2D, MCR3U, MCF3M, MBF3C
http://mathwithbaddrawings.com/2014/10/29/if-trigonometric-functions-could-write-letters/

I think these examples of sculptures made of shadows could easily be connected to 3D vectors. Think about the direction of light rays. 

Curriculum Tags: MCV4U

http://www.theguardian.com/science/alexs-adventures-in-numberland/2014/oct/30/pumpkin-geometry-stunning-shadow-sculptures-that-illuminate-an-ancient-mathematical-technique