Ages 8+ · Coding · How computers work
Binary: on and off
💡 on = 1 ⚫ off = 0
One lamp has two states. The big idea Binary has two states, on and off. Patterns of them can stand for anything.
How it works Binary has two states, on and off. On is written as one, and off is written as zero.
One lamp can make two patterns. Every new lamp doubles the number of patterns.
Patterns can stand for anything, like the letters of the alphabet. Five lamps make 32 patterns, which is plenty for 26 letters.
Computers work the same way, with tiny switches that are on or off. Letters, numbers, pictures and music are all patterns of ones and zeros.
0 10 20 30 40 2 1 lamp 4 2 lamps 8 3 lamps 16 4 lamps 32 5 lamps patterns Patterns for each number of lamps. Example 1: Writing a pattern Lamp 1 is on, lamp 2 is off and lamp 3 is on. On is 1 and off is 0. The pattern is written 101. Example 2: Doubling One lamp makes 2 patterns. A second lamp doubles it: 2 × 2 = 4. A third doubles it again: 4 × 2 = 8. Four lamps make 8 × 2 = 16 patterns, and five lamps make 16 × 2 = 32. Example 3: Two lamps Two lamps make four patterns: both off, the first on, the second on, and both on. Written with ones and zeros: 00, 10, 01 and 11. Each pattern can mean something different. Example 4: How many lamps for the alphabet The alphabet has 26 letters, so Mina needs 26 patterns. Four lamps make only 16 patterns, which is not enough. Five lamps make 32 patterns, which is plenty for every letter. Words to know binary Two states, on and off, written as one and zero. pattern A row of ons and offs, such as 101. switch Something that is on or off. Computers have tiny ones. Watch out On is one and off is zero, not the other way round. Two lamps make four patterns, not two. It takes three lamps to make eight. Each new lamp doubles the patterns. It does not just add one more. A dial or a box of paints has many states, so it is not binary. Try it On, off, on is written in ones and zeros as what? How many patterns can three lamps make? Is a light switch binary, or a volume dial with many settings? How many patterns do four lamps make? Are five lamps enough for the 26 letters? Answers: 1. 101 · 2. 8 · 3. A light switch · 4. 16 · 5. Yes
Try at home With a grown-up, flip a coin three times and write down heads or tails each time. That is a pattern. Can you find all eight patterns? Pick one pattern to mean a word, like yes, and send it to each other by showing the coin.
For grown-ups Do the Mission: flip a coin three times and write heads or tails each time. That is a pattern. See if you can find all eight patterns, and pick one to mean a word such as yes, then send it to each other by showing the coin.