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Why the Towers Fell
The Structure of Metal
Slip

Diagram of metal atoms during slip

When a liquid metal cools and turns into a solid, its atoms come together to form crystals. The structure of these crystals is not perfect. Sometimes an extra layer of atoms squeezes between other layers during the crystal's formation; sometimes there are holes where atoms are missing. Later, after the metal has solidified, these imperfections allow the atoms to shift with less force than would otherwise be needed.

Shown here is an imperfect crystal with its "slip plane" labeled. The slip plane is an imaginary line that divides the whole crystal or part of the crystal into two areas. A typical metal crystal has many slip planes, the result of many imperfectly laid out atoms. These planes lie in all directions throughout the crystal.

To continue to the next section, select Bend.

Metal Basics | Move | Slip | Bend | Heat


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