Grades K–2 · Materials & Matter
How does liquid metal become a solid part with a special shape?
A metal part does not always begin as a block that someone cuts. Some parts begin as very hot liquid metal. A factory makes a mold with a hollow space shaped like the part it needs.
In the diagramA mold gives liquid metal a new shapeA casting illustration · specialist factory equipmentHollow moldMetal has solidifiedEmpty space has a shapeSolid keeps the shapeThe metal cools and becomes solid before the part is removed.
The liquid metal fills the space. The mold holds it in that shape while it cools. When the metal becomes solid, it can keep the new shape by itself.
The mold is opened or taken away, and the solid part comes out. This process is called casting. Real factories also trim, finish and check the parts. The drawing shows the main idea: a hollow space can give a liquid a shape that lasts after it becomes solid.
About this explanation
Starting knowledge: Recognize a hollow space and distinguish liquid from solid.
Sources
- American Foundry Society — About Metalcasting
- American Foundry Society — Permanent Mold