# Pi Day: Ideas for celebrating 3.14

Pi Day (March 14th)  is fast approaching!!  With standardized testing all week, I really haven’t been doing much teaching, so I thought it would be fun to share how I plan to celebrate the biggest math holiday of the year with my classes next week…

My Pi Day celebration begins with a little prep work at home:

– I make a couple of pies to bring in for my classes.  I usually make Oreo Cool Whip pies as they tend to be a hit with the kids (and only take about 5 minutes to make)!  I also allow my students to bring in their own pies so that there is  a variety and something for everybody.

I always use my special pi plate for one of my pies! (A student gave it to me as a gift years ago).

– I also make a bunch of chocolate pi symbols in my pi ice cube tray.  (Another gift from a former student).  I use these as prizes for the games we play in class.

This ice cube tray makes the perfect chocolate pi mold!

– I tell my students a couple of days ahead of time that I will be holding a pi digit memorization contest on Pi Day so they can study the digits if they plan to participate in the contest.  I also do a pi poetry contest where the students who are interested type up a poem about pi ahead of time and bring it in on the big day.

On Pi Day I do different activities with each class

– I have my 6th graders bring in cylindrical objects on 3/14.  I have them “discover” pi by measuring the circumference and diameter of their objects using a string and dividing the circumference by the diameter.  We keep track of everyone’s results and come up with a class average which is (usually) pretty close to pi.  We eat pie during class and the students who entered the poetry contest read their poems to the class.  I then do the memorization contest with them.  The student with the most digits memorized gets one of my chocolate pi’s that I made in the ice cube tray.

– My 7th graders have already learned circumference and area so I have them do a page of challenging pie-themed word problems dealing with circumference & area.  I give a chocolate pi to the student who correctly completes the 5 word problems first.  After the word problems, I play circle bingo with the kids.  The bingo game requires them to either find the radius, diameter, circumference, or area of a circle.  The winner of the bingo game (you guessed it…) gets a chocolate pi!  I then have students share their pi poems and do the memorization contest with my 7th graders.  The kids, of course, eat pie during class, as well.

– I like to play Pi Trivia with my 8th graders while they enjoy their pie.  I break the kids up into groups of 4 and ask them a bunch of random facts relating to Pi.  Each group holds up their answer on a mini whiteboard and I keep track of the score.  The members of the winning group each get a chocolate pi symbol.  Some of the questions are academically focused while others are humor-based.  I conclude class with the poetry reading and memorization contest with them, as I do with my 6th and 7th graders.

– During my lunch, I have some of the other teachers vote on the best pi poems and come up with a winner for each grade level.  The winners, of course, go home with chocolate pi symbols!

– I like to celebrate pi minute with whichever class happens to be in my room at 1:59, too.  We start cheering loudly (and sometimes some of the nearby classes pick up on it and cheer, too)!

All-in-all it is a very fun, exhausting, and FATTENING day….but well worth it!  It’s always a great day!

This bundle contains the Pi discovery activity I do with my 6th graders, the Pi bingo game I play with my 7th graders, and several other circle-themed activities –  Circumference, Area, & More: A Circle Bundle.

I would love to hear ideas of how other teachers celebrate 3.14, so please feel free to share in a comment below!

Wishing you all a very happy Pi Day!!

Christina

# My Spin on Symmetry

Today’s 6th grade lesson was on rotational symmetry.  I have found that students tend to be less familiar and less comfortable with rotational symmetry than they are with line symmetry (and sometimes mix the two up), so I try to find ways to make it more clear and understandable to them.

I had several different shapes cut out ahead of time: an equilateral triangle, isosceles triangle, rectangle, square, rhombus, regular pentagon, irregular hexagon, etc.  I had the students each pick a couple of different shapes and trace them on a piece of paper.

After tracing the shapes, the students were told to use their pen or pencil to hold down the center of the shape.  I had them rotate the shapes and count how many times the cut out shape lined up perfectly with the traced shape (until they got to a full turn around).

I asked the students to try to figure out how many degrees they were able to turn the figure to have it line up with their tracing.  They were able to reason that since a full turn was 360 degrees, they had to divide the number of times they could turn the shape into 360.

Their finished notes for the day looked like this:

As an extension, I gave each of the students an angle measure.  They have to draw, color, and cut out their own figure that has that rotational symmetry.  (For example, the student to which I assigned 120 degrees is not allowed to draw an equilateral triangle.  They have to create their own, original figure that also has 120 degree rotational symmetry).

I am excited to see what they come up with!

Christina

# A Little Sum-thing about Triangles

I started my unit on Geometry with my 6th graders before Christmas break.  We got as far as the basic vocabulary and different types of angles.  I decided to begin with polygons after break, so my first post-Christmas lesson was on triangles.

We started off by discussing the different ways to classify triangles – by their sides and by their angles.  The students made a chart in their notebook listing the different types of triangles and we did some example problems.

[Before the lesson, I had made up little slips of paper with different triangle types on them.]  After going over the basics, I had each student pick one of the slips at random.

They had to draw whatever kind of triangle they picked on construction paper and then cut it out.  This served two purposes – it showed me if they understood the first part of the lesson, and it provided me with a wide variety of triangles.  I had each student number the angles in their triangle (1, 2, and 3).  I then asked the students to rip off each of the angles of their triangle.  Finally, I asked the students to line up their three angles so that they were adjacent to each other, and asked them what they noticed when they arranged their angles in that way.  A few students noted that they formed a straight line.

When I asked the students how many degrees the three angles must be in all if they are forming a straight line, the light bulbs went off!  Since everyone had started with a different triangle, the students were able to conclude that the angle sum of ANY triangle is 180 degrees.

All in all the lesson went very well.  We finished by going through an example of finding the missing angle in a triangle.  The students’ notes for the day ended up looking like this:

At the beginning of the class when we were first going over types of triangles, one of the students had asked why an acute triangle has 3 acute angles, but a right triangle only has 1 right angle and an obtuse triangle only has 1 obtuse angle.  I posed the question back to the class and their original answer was that the triangle wouldn’t close if it had 2 right angles or 2 obtuse angles.  At the end of class, however, one of the boys in my class said “Oh, that’s why there can only be 1 right or obtuse angle…there’s only 180 degrees in all so if you already have 90 degrees, if you had another 90 degree angle you wouldn’t be able to fit another angle!”

Don’t you just love it when students can reason out the answers to their own questions?!