Categories
Algebra Middle School Technology

Desmos Online Graphing Calculator

Recently, I have been noodling around with the Desmos Online Graphing Calculator.  I have used Texas Instruments products exclusively and extensively in my classes for years, but am always on the lookout for tools that are easy to use, functional, and (most importantly) cheap!  The Desmos calculator aligns quite nicely with my personal motto, “If It’s For Free, Then It’s For me!”

The calculator has an interface which is intuitive, and it’s easy to dive right in and start graphing:

desmos1

Inequalities can also be graphed easily and nicely:

desmos2

Trig functions are formatted in readable form as you type them, and you can choose to have the x-axis “count by pi”, which is a pretty cool feature:

desmos3

Points can be traced.  Check out how the minimum here is communicated with appropriate symbols:

Photobucket

Yep, we can do piece-wise functions too:

desmos5

What appeals to me about this calculator is that it is web-based, fires up quickly, and is ready to use.  This site should be on everyone’s links for students, shared on Edmodo, or whatever resources page you use.  While I love my TI software, it often takes too long to load, and you need to be a real Nspire user to navigate around.  The site is also usable with Ipads:

Horsham-20120502-00199, Uploaded by Photobucket Mobile for BlackBerry

But keep in mind that this is a stripped down calculator.  It graphs stuff, and that’s about it.  You’ll still need your TI’s to perform calculations, analyze data, or do more in-depth analysis, like intercepts or integrals.

Sometimes, less bells and whistles are better.

EDIT: check out the comments for news from Eli, founder of Desmos, who gives some more great information about this tool!

Categories
Statistics

NCTM – Saturday

Much quieter here today, as the math folk move out and an antiques show moves in.  But still time for some sessions!

Essential Understandings in Grades 9 – 12 Statistics: Preparing for the Common Core.

Very excited for this session today, as one of the speakers is Roxy Peck, former Chief Reader of the AP Stats exam.  Also, looking for some ideas for our freshman year prob/stat course.

Big ideas –

1.  Data consists of structure + variability: look at math models but explore the big picture

2.  Hypothesis tests answer the question, “do I think this could have occurred by chance?” – what hypothesis is more plausible?

3.  To evaluate an estimator, you need to consider bias and the sampling method.

4.  Describe variability – distinguish different ways distributions are used (population, sample, sampling distributions) and be able to compare them. As more teachers are compelled to teach stats in HS, we need to train for the abstraction of sampling distributions.

How much do sample distributions tend to look like population distributions, and how can samples differ based on randomization?

5.  The way in which data are collected matters.  The is a risk of error that needs to be acknowledged and quantified.  Also, the collection method determines the type of inferential conclusions that can be made.  If the sample is not representative of the population, we should be suspicious of generalization.

“as statistics people, we are OK with being wrong 5% of the time” – Roxy Peck

All HS math teachers will find themselves in the dual role of being teachers of math and teachers of statistics. This is a bit scary to me.  While many resources are coming out which will assist teachers in presenting statistical ideas, I wonder how many math teachers are prepared to facilitate a discussion, perhaps over many class days, centering on one scenario and its many statistical concepts.  A colleague, at the end of the session ,offered that his department is “petrified” of the prospect of being made to teach stats courses.  Many great math teachers I know are like musicians playing classical music, adept and expert in the rhythm and complexity of math.  How many of my colleagues are prepared to become jazz musicians, and have conversations meander in new and exciting directions?

After attending 2 conference in the last month, and moving through meeting rooms, with various degrees of “fullness”, I have begin to develop the “Large Ballroom Theory”

Large ballroom theory:  given a large ballroom with many empty seats, people will

  • Find somebody familiar and sit with them
  • Sit in the back, for easy escapability from intolerable sessions
  • Sit in a location which will maximize the apparent fullness of the room, looking for bare spots

Philadelphia-20120428-00195, Uploaded by Photobucket Mobile for BlackBerry
It is the last bullet which I believe could be the start of a full-blown thesis.  In the photo above, think about where you would sit?  On the end?  Which row?  Someplace equidistant to others?  Or would you sidle up next to a stranger?

Categories
Uncategorized

NCTM – Friday

Back on the train.  Jealous of the students and coaches from my school headed off to Penn Relays on the train, while I get off a few stops earlier for NCTM.  Looking forward to the day…

Supporting the Mathematical Practices: What’s In Your Coaching Toolkit?

This session had an interesting opening activity.  Seven statements about classroom culture were provided, and teachers were asked to assess themselves on a continuum?  Some examples

  • From focus on correct answer towards focus on explanation and understanding.
  • From mathematical authority coming from the teacher or textbook to mathematical authority coming from sound student reasoning.

Already, the activity caused me to reflect upon the textbook-driven culture in schools, and how we approach classroom practice.

How can we provide optimal learning opportunities for students to become mathematically proficient?  The team create a check list of “look-fors” which cover each of the 8 Common Core standards, and shifts in classroom practice which attempt to match the new standards.

This was one of the best sessions I have attended, as I have some great ideas here for guiding the teachers I work with through the increased rigor of the Common Core.

Unfortunately, I am off to a track meet tonight, so today’s post is a quickie.  A late night tonight, then an early train tomorrow for more sessions.