34. Elastic structures
Elastic materials
The function of springs and bows is based on elasticity. Below, you can see examples of different elastic materials.
Rubber bands are made of flexible, elastic rubber.
A rubber rope is made out of an elastic material. This makes it durable and flexible.
A super ball is made out of an elastic material. A basketball is filled with air, which makes it elastic.
Elastic structures
Steel is not an elastic material, but it can be molded into an elastic structure. Steel is mostly made out of iron. Steel springs can be found in many vehicles, such as cars.
Steel springs are used in cars and in ball-point pens. Steel is not an elastic material, but it can be molded into an elastic structure.
Image on the left: The hole punch contains two steel springs. They are elastic structures that compress when pressure is applied to the punch's lever. When the pressure is lifted, they return back to their original shape. Image on the right: Steel springs provide flexibility to the trampoline.
Image on the left: Leaf springs are used in vehicles and machinery. Image on the right: A hunting trap is based on two u-shaped leaf springs.
Bows
The function of a bow is based on the structural elasticity of wood. For example, a dry birch branch is an elastic structure. When it is bent, it tries to return to its original shape.
Long bows (on the left) and crossbows (on the right) are ancient weapons that are based on the structural elasticity of wood.
Long bows and crossbows base their function on the structural elasticity of wood. The third type of bow is the recurve bow. The ends of the recurve bow are bent towards the bow's front. They are made from a blend of different materials.
Recurve bows.
Terminology
| Term | Explanation |
|---|---|
| elastic material | A material that is capable of bending, and always returns to its original shape. E.g. air or rubber. |
| elastic structure | A structure that is capable of bending, and always returns to its original shape. E.g. a spring or a bow. |