The AI's little choices
Why the same question can give you different answers
Ask the same question, get three different answers
Before we say anything else, let's watch it happen.
Pick one of the prompts below. Copy it. Paste it into any AI you have handy (ChatGPT, Microsoft Copilot, Gemini, whichever the class can see). Run the SAME prompt three times, one after the other. Do not change a single word between runs.
Project the three answers at the front and look at them together.
Have you ever asked a friend what game to play at breaktime? They might say football today and tag tomorrow. It depends on what they feel like.
AIs do something a bit like that. You can ask an AI the exact same question three times in a row and get three different answers. It isn't broken, and it isn't being cheeky. That's just how the AI works.
Over the next fifteen minutes or so we're going to see it happen live, work out why it happens, and learn when different is fine and when we really do need the same answer every time.
Please draw a silly cartoon monster wearing a football kit. Bright colours, fun, like a picture from a children's book.
Please pick a random number between 1 and 100. Just tell me the number, nothing else.
Write a two-sentence bedtime story about a hamster who wants to be a pilot.
Look at the three answers together and ask the class:
- Were any two answers exactly the same? Even the number one?
- Which of the three was your favourite? Why?
- If we asked YOUR friend the same question three times, would they give you the exact same answer every time?
- Which of these three prompts felt like it was OK to get a different answer, and which one felt a bit weird?
Give each pupil a small piece of paper. Ask them all to draw a silly monster wearing a football kit. Same instructions for everyone.
Now hold the drawings up at the front. Are any two exactly the same? Almost certainly not. Point out that even people don't do the same thing twice when they get to make choices, and the AI is a bit like that too.
The AI makes tiny choices
The AI is not like a calculator. A calculator sees 2 + 2 and shows 4 every single time, with no surprises at all.
When you ask the AI to draw a monster or write a story, it has to make hundreds of little choices as it goes. Which colour to pick? Which word to use next? Should the monster have three eyes or five? What should the hamster in the story be called?
Each time you run the prompt, the AI can pick a bit differently. That's why the answer changes. It isn't broken and it isn't trying to trick you. It's just choosing, a little like you would choose if someone asked you to tell a joke twice.
Ask the class: 'What did you have for tea last night?' Get a few answers. Now ask: 'What would you pick for tea if you could have anything at all?' Same question, but everyone picks differently.
Now imagine asking them again next Monday. Some pupils will change their minds and pick something else. The AI does the same thing, only faster and every single time.
Sometimes different is great, sometimes it's a problem
A different answer each time is not always a problem. Sometimes it's the whole point. If you ask the AI to draw ten cartoon dragons for a game, you want them ALL to look different. Ten identical dragons would be boring.
But some questions have only ONE right answer. Maths, spelling, dates, the rules of your favourite game. If the AI keeps changing its mind on those, we can't trust anything it says.
Before you tap the cards below, have a guess: for each of these, would you rather the AI gave you the same answer every time, or is it fine to be a bit different?
Tap each card to see when different is fine, and when we need the same answer.
Making up a new game character
Different is BRILLIANT. Every character is meant to be unique. If the AI gave you the same character every time, your game would be very boring.
What is 7 times 8?
Same, always. The answer is 56 every time. If the AI sometimes says 54, we cannot trust it with our homework.
A short poem about the seaside
Different is fine. Poems are creative. Lots of different poems can all be lovely.
How do you spell 'necessary'?
Same, please. There is one correct spelling. We cannot learn if the AI keeps changing it.
The rule of thumb: if there is one right answer (like maths or spelling), we need the AI to give us that same answer every time. If it's creative (like a story or a drawing), different is part of the fun.
Read out five questions one at a time. The class shouts 'SAME' or 'DIFFERENT' for each one.
- What is 12 add 15?
- Draw me a pirate ship.
- Tell me a joke about a snail.
- What is the capital city of France?
- Write a rap about school dinners.
After each one, ask a pupil to say why. If people disagree, that's a great chance to talk about it. Some questions are trickier than they look.
Ask clearly, get closer
The AI will always make tiny choices. We can't stop that. But we CAN help it choose more of the things we actually want, by giving it a clearer question.
If we ask something very open, the AI has loads of room to pick anything. If we ask something clear, with details, the AI has less room to wander off.
Both of the prompts below ask for a story. One is much more likely to give us the story we wanted.
Give me a story.
This tells the AI almost nothing. It has to guess who the story is for, what it's about, how long it should be, and what should happen. Every time you run this, you'll get something completely different, and probably not what you were hoping for.
Write a short story for a Year 4 pupil about a dog called Biscuit who learns to skateboard. Three paragraphs, please. Happy ending.
This closes off most of the guessing. The AI still picks the exact words (so each version is a bit different), but the shape, the subject, the age of the reader, and the ending are all locked in. You'll get a story you can actually use, first try.
In pairs, take each of these very fuzzy prompts and add details until they are clear. Aim for at least a name or subject, a length, and who the answer is for.
- Draw me an animal.
- Write a poem.
- Tell me a joke.
Share the best rewrites with the room. If you can, try one live at the front and see if the AI's answer is closer to what the pupils wanted.
So what would you do?
Time to put everything together. Imagine you're doing your maths homework and there's a tricky sum: 456 x 27.
You ask the AI. The first time it says 12,312. You're not sure, so you run it again. This time it says 12,308. Two different answers!
You know maths has one right answer. You know the AI makes tiny choices each time. What's your best next move?
Read out the four options below. Hands up on which one pupils would pick. Then ask three of them why: one for the strongest option, one for a tempting-but-weak option, and one for whatever the room voted for.
Push them to say what they know about how the AI works. The answer they land on should link back to 'the AI is picking, not calculating'.