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Builder's Lab / Week 04 / Tuesday
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Week 04 · Bridge the Gap

Tuesday

Folds make it stiff
// A paper bridge that holds the most coins
⏱ about 20 min

Tuesday: Folds Make It Stiff

Raven holds a flat sheet of paper by one edge.

The far end droops down like a sleepy leaf.

Then she folds the sheet back and forth, like a fan.

She holds it out again. It sticks straight out!

"Whoa!" Rocket says. Nova hums. "Same paper. What do you notice?"

Shape makes strength

A flat sheet of paper bends very easily.

Folding it back and forth makes ridges, like a fan.

The ridges help the paper stay stiff.

Same paper, new shape, more strength!

Engineers fold things too

Engineers shape materials to make them stronger.

Triangles and folds help a bridge hold its shape.

Try it
Hold a flat sheet by one edge. Watch it droop.
Fold a sheet back and forth like a fan.
Hold it the same way. Watch again.
Safety first
Paper edges can cut. Slide your fingers gently.
A grown-up does any cutting.
PAPER CHECK
  • Read the question.
  • Tap your answer.
Which paper sticks straight out?
What did Raven change?
IdeaTrue or false?
Flat paper bends easily.?
Folds can help paper stay stiff.?
You need new paper to make it stronger.?
WHY THIS EXERCISEChanging the shape can make the same paper much stronger.

Other folds to test

  • Fan folds: back and forth, like a fan.
  • A tube: roll the sheet and lay it across.
  • Folded edges: fold up both long sides like a gutter.

Each shape uses the same one sheet of paper.

FOLD THINKING
  • Read the question.
  • Tap your answer.
Raven folds paper back and forth. What does that make?
A flat sheet droops. Why?
Which change makes the paper stiffer?
Folding paper changes which thing?
MAKE A FAN FOLD
  • Tap a card.
  • Then tap its spot.
1First
2Next
3Then
4Last
Try it
Make a tube, a fan fold and a gutter fold.
Hold each one out by one end.
Which one droops the least?
Safety first
Slide fingers gently along paper edges.
A grown-up does any cutting.
FoldTrue or false?
A gutter fold turns up both long sides.?
Each fold test uses a new kind of paper.?
A tube is one more shape to test.?
WHY THIS EXERCISETesting many shapes helps you pick the best bridge.

You found the paper secret!

Tomorrow, we build bridge version 1.

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