Guess it in 20 questions
You will identify a secret object using at most twenty yes-or-no questions. Broad questions can narrow the options, but only if both partners understand the same category and answer clearly.
- Brain
- Starter
- About 20 minutes
Grown-up needed: yes for selecting safe materials and supervising the setup
What you need
- A partner
- A familiar secret object chosen from an agreed set
- Paper and a pencil
The rule
Twenty questions. Not one more.
How to do it
- Agree a set of familiar objects the answer may come from.
- Have one partner choose an object without naming it.
- Ask a broad yes-or-no question and mark its number.
- Remove options that conflict with the answer.
- Continue with a question that distinguishes remaining possibilities.
- Give a final guess within the twenty-question limit and explain your clues.
Why it works
Each reliable answer removes possibilities that do not fit it. A question dividing the remaining set into similarly sized groups can reduce uncertainty efficiently, but everyday categories rarely halve it perfectly. Ambiguous questions can also mislead because partners may interpret them differently. Agreeing the possible set and clarifying a category helps keep the reasoning shared. Your final guess should fit all recorded answers, not merely the most recent one, and twenty questions need not guarantee success for every possible set.
Make it harder
- Record the remaining possibilities after each answer.
- Compare a broad question with a single-object guess.
- Explain a question that splits your actual remaining set nearly equally.
Ask Taz
- Why do broad questions sometimes narrow options faster?
- Why can an ambiguous category mislead us?
- Why must a guess fit every earlier answer?
For grown-ups
Choose ordinary objects and avoid secret people, private possessions or identifying details. Clarifying what a question means is more useful than enforcing a trick answer. Keep a visible tally so the limit is fair. Ask at dinner: “Which question removed the most possibilities, and how many choices did it actually leave?”
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
Is a wrong answer a failed activity?
No. Keep the first answer and compare it with the revealed objects, timing or rule. That comparison tells you what to change next. The activity offers one observation of a strategy, and it does not provide a general score for intelligence or ability.
How can a grown-up help?
Prepare the safe space and agree the rule before starting. Ask the child to describe the clue or strategy they used, then check the actual result together. Offer a shorter adapted version if needed and say clearly how it differs from the original challenge.
Should we share the result?
Sharing is optional. A discussion at home is enough, and the privacy line above applies to any online post.
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