Tuesday, September 11, 2007

Lesson Plan: Graphing on the Coordinate Plane using "Battleship" game

Yesterday in class we played SINK THE SIR! (a play both on what kids call male teachers in the RGV, "the Sir," and on the old movie Sink the Bismark!), a version of the game Battleship . The main objective is for students to know how to identify and graph points correctly and to learn the necessary vocabulary:
Last year, I found a lesson plan on Education World called Play Battleship on Graph Paper. The only real difference between the real game and the lesson was that the original's grid was replaced with a coordinate plane. I followed this lesson closely, having the students play against each other. The students certainly had a lot of fun, and got familiar with the coordinate plane, but the objectives were totally lost. I did a poor job of explaining the directions and making it easy to do; the result was that students were graphing points incorrectly and confusing each other. Some students were just fooling around because the student vs. student design made monitoring difficult. Later in the year, far too many students still had trouble graphing points accurately, which could be traced directly back to the game.

I was determined to fix the problems and make "Battleship" work for my classroom. The first thing I did was change the game to a whole-class activity: teacher vs. students, sink "The Sir" before he sinks you.

Each student had a graphic organizer with directions, a table for coordinates fired at me and fired at them, and a coordinate plane to keep track of their ships. On the whiteboard I had the plane where everyone could keep track of when they hit or missed "the Sir". After labeling parts of the graph (x and y axes, origin and quadrants), the rest of the game remained the same. The slightly tweaked lesson design allowed me to make sure the objective was covered thoroughly because I could come back to the key points easily:
  1. With each shot made, I could ask students to identify the quadrant or axis where the point was located.
  2. I could also give them multiple options for the location by pointing at my coordinate plane to check that they understand how to read ordered pairs, i.e. knowing the difference between (-2, 3) vs. (3, -2) vs. (2, -3)
  3. I focused on points on the x-axis and y-axis, which the students always mix up.
  4. I was able to give hints to check their understanding, i.e. "One of my ships is located along the y-axis" or "I have a ship in Quadrant II" and then see if the next student fired at the right area.
  5. I also connected the game to graphing linear equations by having my aircraft carrier located along the line y=x (a parent function), discussing how to figure out where that line would be and then aiming at points along it.
The possibilities are endless for how many directions and how much material you can cover in this activity. Since the teacher directs the activity and the students are engaged (because they love competition and love beating you even more), it's easy for you to steer them towards many different objectives. You could easily incorporate:
  • more linear equations
  • domain and range
  • linear inequalities (identifying points that satisfy a linear inequality is a common question on our state standardized math test, like #51 on this released test)
  • transformations
  • quadratic and absolute value equations
You could do this game for half of the class period (as I did due to time constraints), but you wouldn't need more than a regular 45-55 minute period to complete the game and have students complete follow-up practice questions. The students did excellent on practice problems today, so I think this year's version of the game was a great success (time will tell if these concepts remain with them throughout the year).

If you decide to use this lesson, I recommend you change the domain and range of the graph -4 to 4 instead of -5 to 5. The latter was a bit too big and made it take a little longer than necessary for us to sink each other's ships. You could also adapt this to return to the student vs. student format, but I think you then miss out on the possibilities I wrote about above.

It also helps to look the part; I wore a $7 captain's hat from the local costume shop and taped "CAPTAIN" on my school ID. You could also cue up some video or audio clips of torpedoes firing and ships exploding for dramatic effect. Have fun with it--then your students will too!

UPDATE: Check out the revised 2008 edition of this game!