Tonight: people who have never met you use the thing you made.

Setting up

1. Table early. Power on. Check it works before anyone arrives.
2. Card in front, where it can be read from standing.
3. Leave room in front for somebody else's hands. That is the most forgotten thing.
4. Decide who speaks first and who runs the demonstration. Swap every half hour.

What to do when they arrive

• Let them use it themselves. Do not demonstrate at them.
• Explain it in one minute: what it senses, what it decides, what it does.
• When somebody asks “what if it does not work?” — answer honestly. You tested it. You know.
• Write down every question you could not answer. That list is worth more than the compliments.

Afterwards

• Pack down carefully. Every part back in the bin, checked against the card.
• Photograph it before it comes apart. You will want that next year.
• Save your programs somewhere permanent.

Look back at Session 1

You started this book being shown which part of a computer does the thinking. Tonight a stranger walked up to something you designed and built, used it without being told how, and it did what you said it would.

What you can actually do now

• Use a computer properly — find your work, move fast, stay safe.
• Write instructions a machine follows exactly, with loops and decisions.
• Build a circuit that senses something real and acts on it.
• Use a chatbot well, and know when not to trust it.
• Take an idea from one sentence to a finished thing in front of visitors.

What is waiting in Level 2

• The blocks become typed code — and you will see them side by side, so it is not a jump.
• Your machines start moving, with motors and wheels.
• You stop guessing numbers and start measuring them.
• And the question gets harder: not does it work, but how accurate is it?