Glue Inside the Wood: teacher key

How Paper Is Made, grade 5 edition, written for 5th grade. Why wood must be cooked apart, what lignin does, and how a pulp mill runs on its own leftovers.

Read the book. Print this page for the key.

Questions and answers

1. What does lignin do in wood?
   • It makes wood heavy
   • It holds the fibers together (answer)
   • It makes wood blue
2. What does the word kraft come from?
   • A French word for paper
   • A Latin word for tree
   • A Swedish word for strength (answer)
3. What makes newsprint turn yellow as it ages?
   • Lignin left in the ground wood (answer)
   • Too much water
   • Too much clay
4. Why might a mill use bark as fuel?
   • It is a leftover that burns for steam and power (answer)
   • It is cheaper than water
   • It makes paper white
5. What does brittle mean here?
   • Very wet
   • Easily broken (answer)
   • Very white

Words

• lignin: natural wood glue
• digester: pressure cooker
• kraft: strength
• brittle: easily broken