What it shows
Players hide paper ships on a grid running from minus 8 to 8 on both axes and call shots as ordered pairs like (minus 3, 5). Reading x before y and keeping the signs straight is the only way to win, so the game drills plotting points in every quadrant.
The science
A point on the plane is named by an ordered pair (x, y): the first number says how far to go right (positive) or left (negative) from the origin, and the second says how far up or down. The four quadrants are numbered anticlockwise from the top right, so (minus 3, 5) is in the second quadrant and (minus 3, minus 5) in the third. Because each pair names exactly one point, a shot can be checked without argument, which makes the game a fair test of coordinate reading.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- Two shoe-box lids as game boards
- Two sheets of graph paper with axes from minus 8 to 8
- Paper ships of length 2, 3 and 4 squares
- Two colours of small stickers or pins for hits and misses
- A cardboard screen between the boards
Safety
This project uses safe, everyday materials. Still, read the rules below with a parent before you start.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
7 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Glue graph paper into each lid and draw the x axis and y axis through the middle, numbering from minus 8 to 8 and marking the origin.
Label the quadrants I, II, III and IV anticlockwise starting from the top right.
Each player places three ships on grid points, horizontal or vertical, hidden behind the screen, and writes down the coordinates each ship covers.
Players take turns calling a point such as (minus 3, 5). The opponent answers hit or miss and the caller marks the shot on a blank tracking grid.
A ship is sunk when all its points are hit; the first to sink all three ships wins.
After the game, both players check the written ship coordinates against the marked hits to settle any dispute.
Record which quadrant caused the most mistakes and make a rule card for signs.
What you should see
A playable game where every shot is an ordered pair, and the checked coordinate lists show that players plot points correctly in all four quadrants by the end.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1In which quadrant is (minus 4, minus 2)?
The third quadrant, where both x and y are negative.
2What point is at the origin?
(0, 0), where the two axes cross.
3Is (2, 5) the same point as (5, 2)?
No. The order matters: (2, 5) is 2 right and 5 up, while (5, 2) is 5 right and 2 up.
4Where do all points with x = 0 lie?
On the y axis.
Take it further
Allow diagonal ships and ask players to state the slope of each ship, which makes the game a review of gradients too.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
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