Code a rocket countdown
You will count down from five and then print a final message. A negative step changes the direction, while the stopping value decides which numbers appear.
- Code
- Starter
- About 10 minutes
Grown-up needed: yes for choosing and supervising the coding environment
The film says 'Taz, on the Code tab'. In Taz today, choose Make, then Code, and pick Python.
What you need
- Paper and a pencil
- A grown-up-approved Python environment where the steps use code
- A grown-up
- Or the Maker Studio in Taz, in Python mode: open Taz, choose Make, then Code
The rule
It must count backwards.
How to do it
- Write for n in range(5, 0, -1): on the first line.
- Indent print(n) beneath it.
- Write print("Lift off") on a third line without indentation.
- Predict the complete output before running.
- Run it and check that one appears before the final message.
Why it works
The three range arguments specify a starting value, an excluded stopping value and a step. Starting at five with a step of minus one gives five, four, three, two and one before reaching the excluded zero. The indented print instruction runs during each turn. The final unindented instruction runs after the loop has finished. Changing the step to minus two skips values, so that change also affects the last printed number rather than simply making the same countdown faster.
Make it harder
- Start the countdown at eight.
- Predict the output with a minus-two step.
- Include zero by changing the stopping value and explain why.
Ask Taz
- Why is zero missing from this range?
- Why does a negative step count backwards?
- Why does the final message appear only once?
The coding part of Taz is the Maker Studio.
For grown-ups
Choose and supervise the coding environment. The film names a Taz Code tab. In Taz today that is the Maker Studio: choose Make, then Code, and pick Python. Use ordinary sample words and numbers without personal details. Ask at dinner: “Which prediction did you check, and what change in the instructions would change that output?”
Taz is an AI and can be wrong, so stay close by. Read how safety works on Taz.
Show us yours
Film your hands and what you made, not your face or name. Ask a grown-up before posting anywhere else.
Questions parents ask
Can we begin without running code?
Yes. Write the predicted output on paper and trace the steps together. That gives you a comparison to use when a grown-up-approved Python environment is available. A prediction remains a prediction until you check the actual instructions and result.
What if an error appears?
Read the message with a grown-up and compare spelling, punctuation and indentation with the steps. Change one thing at a time and keep a note of what happened. An error is useful evidence about the instructions, not a judgement about the child.
Must we share the result?
No. Discussing the output at home is enough. Follow the privacy line above for optional online sharing.
More to try
See all Taz Challenges, or look through the science labs. One place for every why. Ask for early access at aitaz.com