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Paper Play

Buildings

Paper bridge

Pleat a sheet of paper like a fan and it becomes a bridge between two cups that can hold weight. Test how much stronger folding alone makes the paper.

  • DifficultyIntermediate
  • PaperA4 paper, landscape
  • Steps6
  • About15 min

Why this level: You make 15 even creases by halving, then pleat them exactly, valley and mountain in turn.

You need: 1 sheet of A4 (copy) paper, For the test: 2 cups and a pile of coins

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Story

Lay a sheet of paper across two glasses and it sags as soon as you put anything on it. But pleat the same sheet like a fan and it can hold up a third glass! The oldest record we know of is Joseph Leeming’s book Fun with Paper (Chicago, 1939), and nobody knows who first thought of it. Later it appeared in books of magic tricks and science fun too.

Did you know? A 1963 book called this trick “Strong Paper” and explained that it is the zigzag pleats — the corrugation — that let one thin sheet carry a glass.

Learn more (external sources)

Steps at a glance

  1. 1. Crease in half

    Lay the A4 sheet sideways, coloured side up. Fold the bottom long edge up to the top long edge and unfold.

  2. 2. Crease into quarters

    Fold the bottom edge up to the middle crease and unfold. Fold the top edge down to the middle crease and unfold. There are now 3 creases.

  3. 3. Crease into eighths

    Fold the bottom edge up to the first crease and unfold, then up to the third crease and unfold. Do the same from the top edge. Now there are 7 creases and 8 strips.

  4. 4. Crease into sixteenths

    Fold the bottom edge up to the 1st, 3rd, 5th and 7th creases in turn, unfolding each time. Do the same from the top edge. You get 15 evenly spaced creases (about 1.3 cm apart on A4).

  5. 5. Pleat it like a fan

    Starting from the bottom, fold the creases valley, mountain, valley, mountain… in turn, so the sheet pleats up like a fan. Press every pleat firmly.

  6. 6. Open the pleats a little

    Spread the fan a little until every pleat is at about a right angle. Seen from the end it is a zigzag. That is your paper bridge!

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