Something New Is Made: teacher key

Mixing and Reactions, grade 3 edition, written for 3rd grade. Rust is not iron any more, and mayonnaise holds oil and water together. See how stuff turns into something new.

Read the book. Print this page for the key.

Questions and answers

1. What does iron make with oxygen and water?
   • Mayonnaise
   • Rust (answer)
   • Lecithin
2. What holds oil and water together in mayonnaise?
   • Egg yolk (answer)
   • Lemon juice
   • Beetroot
3. Why do citrus fruits taste sour?
   • Egg yolk is in them
   • Salt is in them
   • They have acids in them (answer)
4. Besides red cabbage, what can make an indicator?
   • Rust
   • Berries (answer)
   • Oil
5. Rust is a new kind of matter. What does that tell you about rust?
   • It is iron again
   • It is a kind of oil
   • It is not iron any more (answer)

Words

• rust: iron's red flakes
• matter: what things are
• lecithin: egg yolk part
• indicator: a color clue