How binary digits work

Steps

1. Tell the children a computer is full of tiny things that can be on or off, like a light switch. One of these is called a bit.
2. Pick four children to be bits. Stand them in a row. Give the 1-dot card to the child on the right.
3. Give the next child the 2-dot card. Ask: how many dots will the next card have? Let them guess without telling them they are wrong.
4. Hand out the 4-dot and 8-dot cards. Talk about the pattern: each card has double the dots of the one before.
5. Each bit can show its card or hide it (turn it over). Call out a number from 0 to 15 and let the bits show or hide cards to make it. Add up the dots you can see.
6. Swap places so everyone gets a turn being a different bit.

Talk about it

• What number do you get if every card is hidden?
• What is the biggest number the four cards can make?
• Where else do we see things that are just on or off?