# Guide for Introducing Coordinate Planes

**Guide for Introducing Coordinate
Planes**

This series of activities and lesson notes is part of a unit in which
the purpose is, “Students will interpret visual information in order to
make informed consumer decisions.” The activities begin with informal
exploration.

**1.
Introduce the series, “Today we will think deeply about a way to
represent data visually.”**

**Pet Choices** (approximately 50 minutes without
extension). Use the Open Author
resource, Pet Choices**.**

**2.
“Now let’s look at another visual representation of data.”**

**Drink Prices** (approximately 15 minutes). Use the Open Educational Resource (OER), Figure This! Challenge #70 along with any of the following
ideas:

Use this as a whole class lesson. Be slow to tell students who are making a conjecture if they are correct or not, giving everyone time to think through the ideas.

Share the graph image and ask, “Is it more expensive to buy drinks at the grocery store or the convenience store?” Do not validate any answers, you are more interested in student reasoning; so after every answer given, ask, “How do you know?”

To lead students into seeing a general pattern rather than just the information they can gather from individual data points, use this series of questions:

o “Name a drink that’s more affordable at the grocery store.”

o “Name a drink that’s more affordable at the convenience store.”

o
“What’s
the most expensive drink?” *(Evian.)*

o
“What’s
the cheapest drink?” *(Nestea or Ginger Ale, depending on where
you purchase it.)*

o
“Is
there a way to answer the question, *Is it
more expensive to buy drinks at the grocery store or the convenience store? *for
these and any other data (drinks) we add to this graph at a glance?”

Take suggestions until someone describes, in some way, the
idea of finding where $1 at the convenience store and $1 at the grocery store
meet. Finding multiple points where the
dollar values meet will create a line from (0, 0) at a 45°
angle. Now is the time to use students’ language
with specific dollar-value examples and help them move to more generalized
statements such as “when the price at the convenience store is equal to the
price at the grocery store.” If they are
ready, formalize the language of *y* = *x* from the generalized statements they
use. (See the answers link at the bottom
of the OER for ways that this can happen using a table.)

**3. Now that students have had a chance to experience
coordinate planes in quadrant 1, follow up by extending the lesson in the
appropriate direction for the class. **There
are three choices below. Each activity
takes *approximately 45 minutes*.

1) Battleship (If needed, use to teach plotting points. Directions for quadrant 1 below.)

2) Pomegraphit (This internet-based activity uses 4 quadrants, informally through Desmos.)

3) Awesome Coordinate Plane (This internet-based activity uses negative numbers and all 4 quadrants through Desmos.)

**Battleship**

Preparation: Pass a sheet grid paper to each student. Ask students to fold in in half. On both halves, draw quadrant 1 of a
coordinate plane on labeled from 0 to +10 on the x-axis and y-axis. On the bottom half, ask students to plot the
locations of five ships. Ships must be
placed vertically or horizontally and fit within the defined area. The five
ships are:

⧠ Aircraft carrier, 5 points long

⧠ Battleship, 4 points long

⧠ Submarine, 3 points long

⧠ Destroyer, 3 points long

⧠ PT-Boat, 2 points long

Playing the Game: (Model how this works by first playing one game with the whole class guessing where you placed your ships before using it with partnered students.)

1. Take turns guessing coordinates (attacking) that may be a location of a ship.

2. The person whose ships are under attack will let the attacker know if their coordinates were a hit or a miss. The attacker then records whether or not their guess was a hit or a miss on their blank coordinate plane in order to keep track.

3. Once all the coordinates of a ship have been hit, tell the attacker that the ship is sunk.

4. Play until one person sinks all of the other person’s ships.