Program the Robot: Grid Paths on Paper

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Page 2
Program the Robot: Grid Paths on Paper
Technology and Computer Science · Computer Science · Grades 7-8 · 50 minutes
Time needed
50 minutes (one class period)
Prep
Copy the 2-page worksheet (one per student). Write the three robot commands on the board
(see Before class).
Technology
None.
Student
independence
Medium-high. Students work alone, then test a program with a partner.
Copies to make
One 2-page worksheet per student
Materials
Pencils, Worksheet, Whiteboard or chalkboard
Goal for today: Students will trace and write short robot programs using forward and turn commands, and will find
and fix one bug in a program.
Before the bell
☐ Copy the worksheet, one per student (2 pages).
☐ Write on the board: F = move forward 1 square. R = turn right (stay in the same square). L = turn left (stay in
the same square).
☐ Also write: The robot starts at A5 facing North (toward row 1, the top of the map). Columns are letters, rows
are numbers.
☐ Keep the answer key on your desk. You do not need to know any computer science.
Say this to start
Today you are going to be the computer. A robot only does exactly what its instructions say, in the order they are
written, so it is your job to follow each instruction without guessing. Use your finger or pencil on the map and move one
command at a time. Later you will fix a program that has a bug and write one of your own.

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Page 3
Run of show
Minutes
What you do
What students do
0–5
Take attendance. Hand out the worksheet and ask
students to read the short box at the top.
Read “How the robot works” and look at
the map.
5–12
Walk through this example on the board. Program: F F R F.
Say: “Start at A5 facing North. F moves to A4. F moves to
A3. R turns us to face East. F moves to B3.” Wait: B3 is a
ROCK, so tell them this program would crash and stop at
A3. Then say: “A robot that crashes is a bug in the
program.”
Follow the example with a finger on the
map.
12–30
Tell students to do questions 1 through 6 on their own.
Walk around. If a student is stuck, ask them to say each
command out loud and move one square at a time.
Trace each program on the map and write
the final square and the direction the robot
faces.
30–38
Tell students to do true or false questions 7 through 9.
Then read the answers to questions 1 through 6 aloud from
the key so students can check their own work.
Answer 7–9 and mark their own answers for
1–6.
38–46
Question 10 is a partner task. Each student writes a
program of 5 to 8 commands, then swaps papers with a
partner who traces it and writes the final square.
Write a program, trade, trace, and compare
results.
46–50
Have students write the exit ticket sentence, then collect
all worksheets.
Finish the exit ticket and hand in the
worksheet.
If things go wrong
• If a student turns the wrong way, remind them: R is a clockwise turn, like a clock hand moving. From North, R
faces East; from East, R faces South.
• If students say they cannot find the answer to question 5, tell them to count how many squares they must go
up and how many across, and remember a turn is also a command.
• If a partner pair disagrees on a trace, have them trace again out loud, one command at a time. The program
has only one right answer.
• If students finish early and talk, send them to the early finisher list.
Early finishers
• On the back, write a program that makes the robot visit both GEM squares. Check it with the map.
• Write a program that puts a new rock in a place where one of your partner’s programs would crash. Explain
which command fails.
Support and challenge
• Support: Let students move a pencil tip or a coin on the map as they trace. Have them do questions 1, 2, 4
and 7–9.
• Challenge: Ask students to write a program with the fewest commands that visits C1 and then ends at E4,
avoiding rocks.

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SP-CS-001 · Free to print and use in your classroom · substituteplans.com
Page 4
Notes for the teacher (you fill this in)
Jot a few lines before you leave. A full Daily Sub Report is in the free Sub Survival Kit at SubstitutePlans.com.
How far the class got / what to pick up next:
Students who were especially helpful:
Anything the teacher should know: