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AI Explorers 3-5 / Week 03 / Friday
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Week 03 · Pictures as Numbers

Friday

Screens all around
// Pixels and color values
⏱ about 15 min

Friday: Screens All Around

Raven holds a magnifying glass up to the lab screen. Tiny dots of light glow underneath.

"What do you notice?" she asks. "The picture is made of tiny lights!"

Rocket squints. "So every screen mixes red, green and blue?"

Nova hovers beside them. "Here is a hint," she says. "Remember the three numbers for each pixel."

Pixels everywhere

Every digital picture is made of pixels.

A screen makes each pixel's color by mixing red, green and blue light.

Each red, green and blue value goes from 0 to 255.

So a photo is really a big grid of numbers.

WEEK REVIEW
  • Read the question.
  • Tap your answer.
What is a pixel?
Which three lights does a screen mix?
What is the biggest color value?
A pixel is red 255, green 255, blue 255. What color is it?
A grid has 8 rows of 8 pixels. How many pixels?
A pixel with red 0, green 0, blue 0 is ____.
RGB stands for red, ____ and blue.
Week reviewTrue or false?
A digital photo is stored as numbers.?
A color value can be 400.?
Counting pixel colors can help sort photos.?
Each pixel needs three color numbers.?
WHY THIS EXERCISEPhotos are grids of numbers, and those numbers can be counted and compared.

Why numbers matter for AI

The sorting model cannot look at a photo the way you do.

It works with the numbers inside the photo.

Next week, we pick out clues called features. Then we build the first sorting model!

ORDER THE COLOR VALUES FROM LEAST TO MOST LIGHT
  • Tap a card.
  • Then tap its spot.
1Least
2Middle
3Most
How many numbers does one pixel need for its color?
WHY THIS EXERCISEThree numbers, one for each light, make every pixel's color.
SPOT THE MISTAKE
  • Read the question.
  • Tap your answer.
Rocket writes a pixel as red 0, green 300, blue 0. What is wrong?
Raven says a 2 by 3 grid has 5 pixels. Is she right?
FROM PHOTO TO SCREEN
  • ?The camera picks up light.
  • ?The photo is saved as pixel numbers.
  • ?The screen reads the numbers.
  • ?The screen mixes red, green and blue light.
  • ?You see the photo.
WHY THIS EXERCISEA photo travels as numbers and turns back into light on a screen.
Try it
Look closely at a printed photo in a magazine or book.
Do you see tiny dots? Printed photos are made of dots too.

Brilliant week, explorer! Tomorrow your family makes secret pixel pictures.

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