Tagged: geometry

the menger sponge with playing cards

An activity chosen by my students during the 2012-2013 school year was to build a level 2 Menger Sponge with playing cards.

     

The relevant mathematical concepts illustrated by the activity can be found in “Expectations from Principles and Standards for School Mathematics Content Standards: Grade 4.”  The three major relevant concepts included working with estimation and multiplication to determine how many cards and how many decks of cards would be needed for the level 2 Menger Sponge project, analyzing attributes of three-dimensional shapes and developing vocabulary to describe the attributes, and recognizing geometric ideas and applying them to problems in the classroom or real life.

   

When students decided they wanted to build a Menger Sponge, first I required them to figure out how many cards we would need.  Second, particularly during the build, students would refer to a “face” and or an edge or a vertex piece.  Third, students recognized that each cube needed to be comprised of “mostly” straight folds.  Otherwise, the cubes would not fit together to form a level 1 sponge without falling apart.  Most importantly, students collaborated at all stages of the project.

 

 

 

 

 

 

This activity was inspired by Dr. Jeanine Mosely’s work building a level 3 Menger Sponge with business cards.  The first time I saw the idea was during a presentation in Atlanta, Georgia at Gathering for Gardner 10.

    

At the end of our project, we used more than 2700 cards.

Find additional photos here.

References:

Menger Sponge from The Institue for Figuring // Online Mathematical Paper Folding http://theiff.org/oexhibits/menger02.html Accessed 10 May 2013.

Menger Sponge from Wikipedia http://en.wikipedia.org/wiki/Menger_sponge Accessed 10 May 2013.

Menger Sponge from WolframAlpha http://www.wolframalpha.com/input/?i=Menger+sponge Accessed 10 May 2013.

Weisstein, Eric W. “Menger Sponge.” From MathWorld–A Wolfram Web Resource. http://mathworld.wolfram.com/MengerSponge.html Accessed 10 May 2013.

pi day 2013

Happy Pi Day (3/14)! Listed below are a few activities related to Pi!  To begin, what do you notice about the date for this year’s Pi Day?  Check the cartoon strip and read the date from either side.

Among other diversions for Pi Day, if you are looking to search Pi for any certain number sequence, such as your phone number, birthday, or any other significant sequence of numbers, this fun site searches Pi (a great opportunity to discuss irrational numbers).

  

Also, if you have extra marbles around, a flat surface, and patience, approximate Pi with an activity found here.

Finally, if you are not aware of Numberphile, you should be.  Below is one of the greatest ideas I have ever seen for calculating Pi!  Also, take very close note of the time of the video… another sign of clever!

References:

Marbles and pi from Find Pi! | Oxford Connect http://oxfordconnect.conted.ox.ac.uk/events/2013/pi-day-live-marcus-du-sautoy/find-pi#marbles Accessed 14 February 2013.

O’Shea, O. & Dudley, U. (2007). The magic numbers of the professor. Washington, DC: The Mathematical Association of America, Inc.

Wells, D. (1997). The penguin dictionary of curious and interesting numbers. New York: Penguin Putnam Inc.

kites and darts

The golden ratio has been a popular topic of conversation in recent weeks. In keeping with the trend, we will look at Penrose Tiles, and specifically, Penrose Magnets. Penrose magnets or tiles are pieces called “kites” and “darts” that can make patterns.

From the Penrose Magnets site: In a large quasicrystal, Kites outnumber Darts 1.618 to 1. This is the famous ratio known as the Golden Ratio (and Phi or Φ). Found in subatomic particles, sunflowers, seashells, and even the spiral of our Galaxy, Phi is at the very heart of nature. Phi is at the heart of our pattern, and is used to both determine the number of tiles needed and the length of the sides of the Darts and Kites.

References:

A quarter century of recreational mathematics, by Martin Gardner from Scientific American http://blogs.scientificamerican.com/observations/2010/05/29/a-quarter-century-of-recreational-m-2010-05-26/ Accessed 24 February 2013

P. Calter (1998) Polygons, tilings, and sacred geometry from Geometry in art & architecture unit 5 http://www.dartmouth.edu/~matc/math5.geometry/unit5/unit5.html#GoldenTriangle Accessed 24 February 2013

S. Cram, Fun with phi from Grey Matters http://headinside.blogspot.com/2010/08/fun-with-phi.html Accessed 24 February 2013