Week 02 · Two Boxes, One Ship
Thursday
A two-column logbook
// Copy one box and lower another
⏱ about 15 min
Track two boxes!
Rocket and Raven study the auto-pilot together.
Two boxes change as the program runs.
It is hard to keep track in your head.
Raven opens her notebook.
She draws a logbook with two columns.
One column for height. One column for speed.
WARM-UP: LOWER THE BOX
- Track the box.
- Tap what Nova says.
set height to 7
lower height by 2
say height
?
set height to 2
change height by 3
lower height by 1
say height
?
A two-column logbook
Each row is one line of the program.
Write what each box holds after it.
An empty box stays blank.
set height to 4 set speed to height lower height by 2 change speed by 1 say height
What do you notice?
Each line changes one box at most.
The other box copies down unchanged.
Nova says 2 at the end.
TRACK BOTH BOXES
- Keep a logbook in your head.
- Tap what Nova says.
set height to 3
set speed to height
change speed by 2
say speed
?
set height to 6
set speed to height
lower height by 2
say height
?
set speed to 1
set height to 5
set speed to height
lower speed by 2
say speed
?
Now build a program from a logbook.
Match the numbers, row by row.
MATCH THE LOGBOOK
- Look at each row of the logbook.
- Put the lines in that order.
1line 1
2line 2
3line 3
4line 4
Logbook check
Nova wrote a logbook.
Check every row. Is it right?
set height to 2 set speed to height change height by 3 lower speed by 1 say speed
A line only changes the box it names.
| after | height | speed | true? |
|---|---|---|---|
| line 1 | 2 | blank | ? |
| line 2 | 2 | 2 | ? |
| line 3 | 5 | 5 | ? |
| line 4 | 5 | 1 | ? |
Logbook champions!
A logbook tracks both boxes.
One row for every line.
Tomorrow: your own flights!