Twitter-like in Calculus

Recently I tried to embrace the idea of using twitter in my calculus class.  I used the website www.polleverywhere.com  this site can create a Twitter-like environment for my students. 

Two essential ideas of calculus are deriving the slope at a specific point of a non-constant function, and determining the limit of a function at a point.  Without boring all my non-math followers, these are ideas which can be explained many different ways and some students have a trouble understanding them as they are quite abstract. 

The task:

My students, in groups of 4, had to come up with the process of determining the slope and a limit at a point.  As I circulated through the class I noticed some groups had a lot of extraneous information on their page.  Trying to promote a concise solution, I loaded up the website and asked my students to take out their cell phones. 

Each group had at least one person who had a cell phone with an unlimited text plan.  Students where then required to text in an answer, for both questions one at a time, using 140 characters or less.  I turned off my projector and gave my students time to think.

In the picture is one snapshot of the answers.

The learning did not stop there.  As a group, we went through the answers and critiqued them, adding any missing information, or taking out non-needed information.  I was amazed at the engagement and learning that occurred.  Students were even “googling” "when can you not find the derivative"; a concept that was going to be introduced later in the week.

Math is no longer "Page 46, the odds" out of a textbook.  If you put emphasis on repetition, in your math class, then I forewarn you that your students were learn to hate the repetitive nature you are asking them to do.  If you don't believe me, and you teach through repetition, I ask some small favour:  Ask your students if they find merit in your daily homework, and if you made the homework truly optional would they still complete it?