Programming Essentials in Scratch: Unit Exam B
Reading and tracing Scratch scripts, choosing blocks, loops that repeat until a condition is true, and finding bugs.
Instructions
- Time allowed
- 25 minutes
- Total marks
- 25
- Calculator
- No calculator is permitted.
- Answer all the questions.
- The number of marks for each question is shown in brackets. Use it as a guide to how much to write.
- The clock at the top counts down from the real time allowed. When it reaches zero the paper is locked and marked, as it would be collected in the exam hall.
- Read every question to the end before answering. Where a question says tick two boxes, tick exactly two: ticking more than asked scores nothing. Type one word and number answers carefully, because they are marked exactly.
Questions
Answer every question, then finish the paper to have it marked. Marking as you go teaches you far less.
Tick one box.
- LC Instructions carried out in the order they are written
Sequence means the instructions run one after another, in order.
set [lives] to 3
change [lives] by -1
change [lives] by -1
say (lives)- L1
3 - 1 - 1 = 1.
| Motion | Looks | Sound | Control | |
|---|---|---|---|---|
| move 10 steps | ||||
| say Hello for 2 seconds | ||||
| play sound meow | ||||
| repeat 10 |
Tick one box in each row.
- Lmove 10 steps: Motion
- Lsay Hello for 2 seconds: Looks
- Lplay sound meow: Sound
- Lrepeat 10: Control
Movement blocks are Motion, speech and costumes are Looks, playing sounds is Sound, and loops are Control.
Tick one box.
- LB score < 10
7 is less than 10. It is not greater than 7, not equal to 8 and not greater than 9.
repeat until <(score) = 10>
change [score] by 2
end- L3
4 becomes 6, then 8, then 10. After the third pass the condition is true and the loop stops.
set [count] to 1
repeat 3
change [count] by (count)
end| After pass | count |
|---|---|
| 1 | |
| 2 | |
| 3 |
- L2
- L4
- L8
Adding count to itself doubles it each pass: 1 becomes 2, then 4, then 8.
Tick one box.
- LD if on edge, bounce
if on edge, bounce turns the sprite round at the edge.
- LThe score changes during the game
- LA variable holds the current value and can be updated by blocks, whereas a typed number stays fixed
The score changes all through the game. A variable stores the current value and blocks can update it, whereas a number typed into a say block never changes.
Tick one box.
- LA if then else
if then else chooses between two actions.
Tick two boxes.
- LB Show the variable on the stage to watch its value change
- LD Click one script at a time and watch what it does
- LNo marks if more than 2 boxes are ticked
Running small parts and watching variables shows where the program stops doing what you expect.
repeat 5
change y by 30
end- L50
-100 + 5 x 30 = -100 + 150 = 50.
- LAn event block such as when green flag clicked starts the script
- LA forever loop so it keeps happening for the whole game
- LInside the loop, point towards the player and move a few steps (or glide to the player)
Start with when green flag clicked. Under it put a forever loop, and inside the loop put point towards Player and move 3 steps, so every pass turns the enemy to face the player and moves it a little closer.
- L60
A hexagon has six sides, so each turn is 360 / 6 = 60 degrees.
| True | False | |
|---|---|---|
| A forever loop stops on its own after a while | ||
| A Scratch variable can hold words as well as numbers | ||
| Blocks inside repeat 3 run three times |
Tick one box in each row.
- LA forever loop stops on its own after a while: False
- LA Scratch variable can hold words as well as numbers: True
- LBlocks inside repeat 3 run three times: True
A forever loop never stops by itself. Variables can hold text or numbers. A repeat 3 loop runs its blocks three times.
This is an original Key Stage 3 assessment. Most questions are closed, so the marking is exact, and the written answers are marked against a mark scheme in the same style as a GCSE paper, so the format is familiar long before it counts.