The 42-Degree Arch: teacher key

Rainbows, grade 6 edition, written for 6th grade. A rainbow forms where you look about 42 degrees from the point opposite the sun. See why it is round and why a high sun hides it.

Read the book. Print this page for the key.

Questions and answers

1. Where does the main rainbow form?
   • About 42 degrees from the antisolar point (answer)
   • Right at the sun
   • Straight overhead
2. Why is a rainbow round?
   • Clouds are round
   • Every direction 42 degrees from the antisolar point makes a circle (answer)
   • The sun is round
3. What happens if the sun is more than 42 degrees high?
   • The rainbow doubles
   • The rainbow turns white
   • No rainbow can be seen from the ground (answer)
4. What kind of drops make bright, vivid rainbows?
   • Big drops (answer)
   • Tiny drops
   • Frozen drops
5. Why is a rainbow best seen early or late in the day?
   • The rain is warm
   • The sun is low (answer)
   • Clouds are gone
6. What does vivid mean here?
   • Small and plain
   • Cold and wet
   • Bright and strong (answer)

Words

• antisolar: sun's opposite
• degrees: angle units
• horizon: sky's bottom edge
• vivid: bright, strong