CS Unplugged activity

Solo Battleship: lesson plan

A short teacher-led plan for Solo Battleship: find a hidden fleet using only the row and column counts. About 50 minutes. Leaving it for a sub? Use the box below.

For a sub: the 2-minute version

Skip everything below this box. Nothing to set up.

Hand out the worksheet, one per student. Names on top.
Say: “Ships are hiding on the grid. The numbers tell you how many ship squares are in each row and column. Start with any row or column marked 0: it’s all water.”
If the teacher left more puzzles, hand the next one to each student who finishes: a new puzzle (start with 5 by 5 easy).
Restless room? Let neighbors work in pairs. Talking about the puzzle is fine.
Collect every sheet, finished or not.

Stuck? Mark water with a dot. Every dot makes the next move easier. Logic puzzles can stall some students; let them work in pairs early rather than late.

Before the sub day (teacher, or whoever preps the sub folder): print one copy of the worksheet per student, plus keep-going sheets from the New set page: set Copies to your class size and Sets per student to 2 (front and back). That covers a full period even for your fastest students.

Students will be able to

Use row and column counts to work out where ships must (and can’t) be.
Explain the difference between a sure step and a heuristic (a rule of thumb).

Before class

Print one worksheet per student.
Print keep-going sheets from the New set page: Copies = class size, Sets per student = 2. Use 5x5 easy for most students and 6x6 for the ones who fly through.

The lesson

1. Hook (5 minutes)

Ask who has played Battleship. “What if you got the answers to every guess at once, as numbers on the edges? Could you find the fleet without guessing?”

2. The small one, together (10 minutes)

Do Try a small one first on the board as a class. Say every move out loud: “This column says 0, so it’s all water.” Students copy along.

3. The puzzles (20 minutes)

Students solve the puzzles on their own. When one stalls, ask: “Which row or column is already full?” Filling it with water is always a safe move.

4. Keep going (as students finish)

Keep-going sheets, smaller grids first.

5. Wrap-up (5 minutes)

Read the Computer science connection box together. Ask for one sure step and one heuristic students used.