Each # is a colored square, and each . is a white one.
The big ideaA picture on a screen is a grid of tiny squares called pixels.
How it works
A picture on a screen is a grid of tiny squares of color. Each square is a pixel, and each pixel has just one color.
Together the pixels make a picture, like the tiles in a mosaic. From far away, the squares blend into a smooth picture.
More pixels mean more tiny squares, so the picture shows more detail. A photo has millions of pixels.
A computer remembers each pixel as numbers made of ones and zeros, so a picture is a long list of numbers.
More squares, more detail.
Example 1: Counting a grid
A 4 by 4 grid has 4 rows of 4 squares.
4 × 4 = 16.
Sixteen squares make a blocky picture.
Example 2: A bigger grid
An 8 by 8 grid has 8 rows of 8 squares.
8 × 8 = 64.
Sixty-four squares make a clearer picture.
Example 3: Smoother still
A 16 by 16 grid has 16 rows of 16 squares.
16 × 16 = 256.
Two hundred fifty-six squares make the curves look smoother.
Example 4: How many more
Teo's 4 by 4 grid has 16 squares, and his 8 by 8 grid has 64.
64 - 16 = 48.
The 8 by 8 grid has 48 more squares to show detail.
Words to know
pixel
One tiny square of color on a screen.
grid
Rows and columns of squares.
detail
The small parts of a picture you can see.
zoom
To look closer at a picture.
Watch out
Up close, a screen picture is squares, not smooth lines.
Each pixel is one color. It never holds two colors.
A pencil drawing, a painting and a chalk drawing are not made of pixels.
A smooth heart needs more, smaller squares, not fewer.
Try it
What is a pixel?
How many squares are in a 4 by 4 grid?
Which looks smoother: an 8 by 8 grid or a 16 by 16 grid?
Is a pencil drawing on paper made of pixels?
How does a computer remember a pixel?
Answers: 1. One tiny square of color · 2. 16 · 3. The 16 by 16 grid · 4. No · 5. As numbers
Try at homeWith a grown-up, draw a grid on paper, or use squared paper. Colour in squares to make a tiny picture, like a heart or a smiley face. Make a small grid and a big grid. Which picture looks smoother?
For grown-upsDo the Mission: draw a grid on paper, or use squared paper, and color in squares to make a tiny picture like a heart or a smiley face. Make a small grid and a big grid, and ask which picture looks smoother.
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