Paper That Holds Books

Making · Crafts · Page 1 of 5

Name Date
DIRECTIONS: Fold the same paper into three shapes. Build all three before testing any.
1Build the three shapes
→
2Turn over: guess, then test
Scissors only, with a grown-up in the room. If a step seems to want a knife, snip or fold instead.
What you need: paper · tape · books · scissors · a ruler · a pencil. Three or four sheets of the same paper; two piles of books a hand-span apart, and more books to load.
ShapeHow to make it
FlatLay the sheet flat across the gap between the two piles.
A tubeRoll the sheet into a tube about as thick as your thumb and tape it along the seam. Stand it up on end.
A concertinaFold the sheet backwards and forwards like a fan, about a finger-width each fold. Lay it across the gap.
Use the same paper every time, or you only learn that thick paper is strong.

Guess First

Making · Crafts · Page 2 of 5

DIRECTIONS: Guess all three before you test any, in pen.
ShapeHow many books do you think it will hold?How many did it actually hold?
Flat
A tube
A concertina
One book at a time. Count the last one that stayed up. Not precious books: it goes suddenly.
  1. Which shape did you think would be strongest, and why did you think that?
  2. Were you right? Write down what actually happened, even if it is embarrassing.
  3. How many times more than the flat sheet did the best one hold?

Why It Works

Making · Crafts · Page 3 of 5

DIRECTIONS: Read the box, then look at the pictures end-on.
Same paper, so why stronger? Bend something and the top squashes, the bottom stretches, and the middle does almost nothing. Strength comes from material FAR from the middle. A flat sheet is all middle.
FLATall of it in the middleA TUBEall of it far from the middleA CONCERTINAabove and below, one way only
A tube does it in every direction; a concertina in one. Push a concertina the other way and it folds like a fan.
  1. Push down on your concertina from the side instead of from above. What happens, and why?
  2. Why is a tube better than a concertina, using the word middle?

You Have Seen This Every Day

Making · Crafts · Page 4 of 5

DIRECTIONS: Find a real cardboard box. Tear an edge open and look at the cut end.
Cardboard is a concertina glued between two flat sheets. Crush the wavy bit and it goes flat.
  1. Draw what the torn edge of the cardboard looks like, end-on.
    Draw it here
  2. Squash the wavy layer flat between your fingers and press again. What has changed?
  3. Name two other things you have seen that are strong because they are tubes.

Build a Bridge

Making · Crafts · Page 5 of 5

DIRECTIONS: Span the gap between two chairs with paper and tape, and hold up as much as you can.
The rules: paper and tape only · it has to span the whole gap on its own · and there is a limit of five sheets, so you cannot win by using more paper. Weigh what it holds, or count books.
Try at least three: several thin tubes instead of one fat one · tubes taped side by side · a concertina on two tubes · a tube inside a tube.
What I builtHow much it heldHow it failed
Last column: where it broke, not "it broke". The tube crushed at the end, the tape peeled, it rolled, the middle folded.