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AI Explorers 6-8 / Week 03 / Friday
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Week 03 · Encoding the World

Friday

Encodings all around
// Pixels, color values and feature tables
⏱ about 20 min

Friday: Encodings All Around

Raven video-calls her grandmother from the station. The picture freezes and turns into large, blurry blocks.

"The connection is weak," Rocket says. "The screen is getting fewer numbers, so it shows bigger squares."

Raven laughs. "Grandma looks like one of our 4 by 4 relay grids."

Nova hovers nearby. "Every screen you see is doing the same thing," she says. "Turning numbers back into colored light."

"And every time someone chooses an encoding," Raven says, "they decide what to keep and what to lose."

Screens and encodings

Every screen is a grid of pixels. Each one shows its color by mixing red, green and blue light.

The pictures, videos and drawings on a screen are all stored as numbers before they are shown.

Different encodings make different trade-offs. More numbers keep more detail but take more space and time.

Fewer numbers are quicker to send, but the picture can turn blocky or lose small things, like a faint comet.

SPOT THE TRADE-OFF
  • Read the question.
  • Tap your answer.
A picture is sent with fewer numbers. What is gained?
A picture is sent with fewer numbers. What might be lost?
Why might Sky Sorter miss a faint comet in a very coarse grid?

Safe habits for explorers

Photos you take are stored as numbers, and those numbers can be copied and shared quickly.

Never type personal information into any app or website, and ask a grown-up before sharing photos or using any AI tool.

If something online is upsetting or asks for secrets, stop and tell a trusted adult.

Week reviewTrue or false?
A digital picture is made of many small spots of color called pixels.?
Each red, green or blue value runs from 0 to 255.?
All three values at 0 make white.?
A feature row describes one example as a row of numbers.?
Every encoding keeps every bit of information.?
WHY THIS EXERCISEPixels, values and features are how Sky Sorter will see every card from now on.
OUR WEEK, IN ORDER
  • ?We zoomed in until a snapshot became pixels.
  • ?We decoded a comet from brightness values.
  • ?We found encodings and trade-offs in everyday life.
  • ?We built Sky Sorter's first feature table.
  • ?We turned colors into red, green and blue values.
WHY THIS EXERCISEThe week moved from the picture, to numbers, to features a sorter can use.
All three values at 255 make which color? Type one word.
WHY THIS EXERCISEKnowing the ends of the scale, white at 255 and black at 0, lets you read any pixel.
A row of numbers describing one example is a feature ____.
Lower values make a pixel ____.
Try it
Find a screen with a grown-up and look at it closely, perhaps with a magnifying glass.
Can you see tiny spots? Describe what you notice.
On paper, draw one snapshot card three ways: as a sketch, as a grid of brightness values and as one feature row.

Excellent week, explorer. Tomorrow's Explorer Quest is a secret picture swap.

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