Card Towers and Linear Equations

I like to use alternative ways of assessing students' understanding.  A couple of years ago I used card houses as a way to teach algebraic expressions to my algebra and pre-algebra students.  This year, I designed a lesson where students built card towers, gathered data, then created a poster describing the method of building, the dependent and independent variables, the linear equation resulting, and a graph of their results.  Students used their equations to predict the height from the floor of a 10-story card tower, a 25-story card tower, and 131-story card tower, which is the height of the world record tower to date. Each pair of students presented their findings in poster format for their grade.  Oh, and I added a prize for the tallest free standing tower.  We began the lesson with a short video showing the record holder for the tallest card tower.  Our efforts were hampered by the new decks of cards I had purchased which were slippery.  However, that challenge spurred the students on to more innovative tower building strategies, as you can see from the photos here.  I did not get a photo of an interesting strategy that involved a series of boxes made from cards, stacked on one another.  The winning tower, shown above, was three stories tall, 27 cm.  They won their choice of sports-themed hacky sacks, a popular prize.  This year, I teach my eighth graders twice on Fridays so a longer plan such as this fits the bill.  I gave the students 30 minutes to build their towers, and used an online timer.  The lesson was successful, and produced great results. 

And, we had a lot of comic relief as the timer ticked down and the slippery cards slipped.  It was very interesting, and all were engaged.