💻 Station 7: The Present Day 💻
Binary — How Computers Count
The journey ends in your pocket. Every photo, game, and song your phone has ever shown you is made of exactly two digits: 0 and 1. Flip the switches and see how — then paint with three binary numbers.
🎚️ The Light-Switch Machine
A computer is packed with billions of microscopic switches. Each one is OFF (0) or ON (1) — that's the entire alphabet. Here are 8 of them. Each switch is worth double the one to its right. Flip some on and read the total. This machine is the computer talking to humans — switches in, ordinary base-10 numbers out:
Add up the numbers under the ON switches — that's all binary is!
🔡 The Hex Machine — programmer talk
Binary is the computer's language and base 10 is ours — but programmers writing code use a third one: hexadecimal ("hex"), base 16. It works like every system on this journey — place value — and to write any byte you only need TWO places: a ones place and a sixteens place. Base 16 needs sixteen digits, so after 9 the letters pitch in: A=10 up to F=15. Spin the dials and watch all three languages say the same number:
Same trick as base 10 — each place is worth 16× the one to its right. Read it: (left digit × 16) + (right digit × 1).
🧠 Five secrets of the machine — tap a card
Electricity is messy — but "current flowing" vs "no current" is crystal clear, even in a chip the size of a fingernail holding billions of switches. Two clean states means two digits. Binary isn't weird — it's the same place-value idea as our base 10, rebuilt for switches: places are worth 1, 2, 4, 8, 16… doubling instead of ×10.
Computers bundle switches into groups of 8, called a byte. All 8 on = 11111111 = 255, so one byte holds a number from 0 to 255 — that's 256 values (don't forget zero!). This is why so many computer numbers stop at 255: it's a byte maxed out. Each color channel on your screen gets exactly one byte.
A screen starts black and every pixel has three tiny lights: Red, Green, and Blue. Each gets a byte (0–255). Adding light makes things brighter: red + green light = yellow (really!), and all three blasting = white. Every color you've ever seen on a screen is just three binary numbers.
Paper starts white — it's already reflecting all the light. Ink can only take light away. So printers use the opposite team: Cyan soaks up red, Magenta soaks up green, Yellow soaks up blue. Mix all three and you get… muddy dark brown. That's why printers carry a real black ink too — the K in CMYK. The video below tells the whole story.
Nobody wants to type 111111111100100000101000. Hex fixes it with plain old place value, base 16: two places — worth 16 and 1 — cover a whole byte, so any color is six characters: #FFC828 means Red FF, Green C8, Blue 28. Crack a pair the place-value way: (left digit × 16) + (right digit × 1), so C8 = 12 × 16 + 8 = 200. (Bonus fact for future programmers: one hex digit also happens to equal four switches — that's why the fit is so tidy.)
🎨 The RGB Color Mixer
You're now the pixel. Slide each light from 0 to 255 and watch the color — then try Match Mode: recreate the target color and earn the confetti.
The target's code is showing — crack the hex pairs into base 10 (the Hex Machine above is your decoder!) and you can set the sliders EXACTLY. Or hunt by eye, like finding yellow… which is NOT where you think.
🖨️ The printer mystery — the video
You mixed colors by adding light. So why does the printer on your desk refuse to use red, green, and blue — and what's that mysterious fourth cartridge? This video solves it:
🍎 For teachers & parents
This station lands the whole journey: base 60, base 20, base 10, and base 2 are one idea — place value — with different bases. The Code-Breaker Kit has decode/encode practice, the color recipes, and the screens-vs-printers questions, with a full answer key on the last page.
💡 The big idea
A Babylonian scribe, a Mayan astronomer, and your phone are all doing the same thing: place value. Change the base — 60, 20, 10, 2 — and you change the civilization. The digits 0 and 1 don't look like much, but stack up eight of them and you can name any of 256 numbers; use three of those and you can paint sixteen million colors.