Skip to content
KinPilot™Learn & Explore
Menu
← TopicsReading path →

Grades K–2 · Everyday Life

How do folds and joins make an envelope hold a letter?

An envelope is a paper cover for a letter. Folds turn a flat sheet into a shape with a front, a back and flaps. The letter sits inside that cover.

J21 visual explanationA cutaway drawing of a simple paper envelope with joined sides and bottom and a letter inside. The top flap is sealed. Folding shapes a pocket; the side and bottom joins close edges, while the top seal holds the flap. The structure is neither waterproof nor indestructible and is not a particular postal-security claim.Folds and seals keep a letter togetherA simple joined-paper envelope · cutaway drawingLetter insideThe seal holds the top flap down.Joined sides, bottom and flap form a paper pocket.

In the diagramFolds and seals keep a letter togetherA simple joined-paper envelope · cutaway drawingLetter insideThe seal holds the top flap down.Joined sides, bottom and flap form a paper pocket.

The initial cutaway shows a letter inside an envelope with joined sides and bottom and a folded, sealed top flap.

Joins along the sides and bottom keep those edges together. They form a pocket instead of leaving the paper open on every side. The top flap covers the remaining opening.

A seal holds the top flap down. Folding and joining have different jobs: one shapes the paper, and the other keeps parts together. The cover is still made of paper and can tear.

About this explanation

Starting knowledge: Recognize a letter, a paper fold and an opening that can be covered.

Sources

  • Smithsonian National Postal Museum — Envelope Making Machines
← Grades K–2 topics