Presentation: Programming a Mars Rover to Collect Rock Samples

Slide 1 of 7 · Settling starter · Computing · Year 3

5 minutes

Programming a Mars Rover to Collect Rock Samples

Year 3 at Ysgol Glan Ffrwd have a toy rover and a floor map of a crater on Mars. The rover must drive from its base to collect rocks for scientists. It only does what the cards tell it.

While the register is called: write your name, class and date on your worksheet. Find the base, the crater and the soft sand on the map.

Starter question: Why can’t drivers on Earth steer a Mars rover like a remote-control car? The answer is in section 3 of the stimulus sheet.

DCF: Data and computational thinking → Problem-solving and modelling No computers or robots needed · use your finger on the map

Supply teacher script (no subject knowledge needed)

Hand out: one worksheet per pupil and the stimulus sheet Mars crater map and rover command cards, one between two. Pupils can move a finger, a rubber or a counter along the map.

Say aloud: “Write your name, class and date at the top. While I take the register, find the base, the crater and the soft sand on the map.” Then read “What you are doing” on the worksheet and section 3 of the stimulus sheet aloud. Act out the 3 cards with the class: step forward, make a quarter turn right, then a quarter turn left.

Starter answer: Mars is so far away that a radio message from Earth takes between about 3 and 22 minutes to get there. So drivers send the rover a list of instructions, a program, and the rover follows it.

Slide 2 of 7 · Today’s brief and key words · Computing · Year 3

3 minutes

Your job: follow, fix and write rover programs

You will follow programs, fix programs that go wrong and write your own. The rover must not drive into the crater or the soft sand, and it cannot drive over the cliffs.

F (Forward)

Move 1 square the way the rover is facing.

R (Turn right)

A quarter turn clockwise. The rover stays on the same square.

L (Turn left)

A quarter turn anticlockwise. The rover stays on the same square.

LNF: Numeracy → Geometry and measurement → Angle A turn does not move the rover to a new square

Slide 3 of 7 · Steps 1 and 2: follow Programs A and B · Computing · Year 3

10 minutes

Step 1 & Step 2: follow the cards one at a time

Step 1, Program A: the rover starts at the base, facing up. Put your finger on the base. Follow F F F. Which rock does it reach?

Program A: F F F moves the rover up 3 squares. It reaches the layered rock.

Step 2, Program B: start on the layered rock, facing up. Follow R F F F. Which way does it face after card 1? Which rock does it reach?

Steps 1 and 2 on your worksheet · 10 minutes One finger, one card at a time

Slide 4 of 7 · Steps 3 and 4: find the bugs, write your own · Computing · Year 3

17 minutes

Step 3 & Step 4: fix the bugs, then write your own program

Step 3: Cai and Megan both tried to send the rover from the base (facing up) to the red rock. Both programs have a bug. Follow each one until it goes wrong.

Cai: R F F F F F R F. His rover reaches the bottom right corner, then card 7 (R) turns it to face down and card 8 drives over the cliff.

Step 4: the rover is on the red rock, facing up. Write a program to reach the speckled rock. Keep away from the soft sand! Fill in the turn column for each turn card, then test it with your finger.

Steps 3 and 4 on your worksheet · 17 minutes Bug found? Write the fixed program, one letter per box

Supply teacher script (no subject knowledge needed)

Say aloud: “Follow Cai’s program with your finger. The board tells you where it goes wrong. Now follow Megan’s program and find where her rover ends up. Write the fixed program in the 8 boxes. Then write your own program in Step 4 and test it.”

Quick check, Step 3: (a) Cai’s bug is card 7: R should be L. (b) Megan’s rover only goes 4 squares right, so when it turns and goes up it drives into the soft sand. She needs one more F before the L. (c) Fixed program: R F F F F F L F.

Quick check, Step 4: one correct route is F F L F F (card 3, L, is a quarter turn anticlockwise). Another is F L F F R F. Wrong: L F F R F F, because the first F drives into the soft sand. Any route that never touches the crater or the soft sand is correct.

Slide 5 of 7 · Steps 5 and 6: name the turns, use a repeat · Computing · Year 3

15 minutes

Step 5 & Step 6: name every turn, then make it shorter

Step 5: the rover turns on the spot. Two quarter turns the same way make a half turn. Draw the arrow and name each turn.

Starts facing	Cards	Ends facing	Name the turn
up	R	right	quarter turn clockwise

Step 6: your fixed program has F 5 times in a row. Write it again using Repeat 5 times: F. How many instructions did you save?

Steps 5 and 6 on your worksheet · 15 minutes Quarter or half? Clockwise or anticlockwise?

Slide 6 of 7 · Partner test and self check · Computing · Year 3

5 minutes

Swap with a partner: test their Step 4 program

Swap worksheets. Put your finger on the red rock, facing up, and follow your partner’s program. Does it reach the speckled rock without touching the soft sand?

I can follow a program one card at a time.
I can find a bug and fix it.
I can write a program and test it.
I can name a quarter turn and a half turn, clockwise and anticlockwise.

5 minutes · partner test Finished? Write one program that collects all 3 rocks from the base

Slide 7 of 7 · Plenary review · Computing · Year 3

5 minutes

Let’s check our answers together

Answer together as a class, then check your sheet.

Question	Correct answer
Which card was Cai’s bug, and what should it be?	Card 7. R should be L.
The rover faces up and does R R. Which way does it face? What is the turn called?	Down. A half turn clockwise.
Why must the rover keep away from soft sand?	In 2009 the rover Spirit got stuck in soft ground on Mars and never drove again.

Check your name and class are on your worksheet Leave the map sheets neat on the desk