Proof That Earth Turns: teacher key

Day and Night, grade 9 edition, written for 9th grade. You cannot feel Earth spin, yet its turning bends winds, bends sunlight and keeps the Sun up all night near the pole. See the evidence for a moving planet.

Read the book. Print this page for the key.

Questions and answers

1. About how fast does a spot on the equator move as Earth turns?
   • 1,675 kilometers per hour (answer)
   • 40,075 kilometers per hour
   • 23.93 kilometers per hour
2. Why is a sidereal day shorter than a solar day?
   • Earth's trip around the Sun adds one turn to the count relative to the Sun (answer)
   • The Moon pulls the day shorter
   • Earth spins faster in winter
3. Which way is moving air deflected in the Northern Hemisphere?
   • To the left
   • To the right (answer)
   • Straight up
4. What lifts the Sun into view for the midnight sun beyond the Arctic Circle?
   • Refraction (answer)
   • Melatonin
   • Tides
5. What did Mairan's plant show?
   • Leaves can still open and close each day in constant darkness (answer)
   • Plants need no light
   • Plants face west
6. What does nocturnal mean?
   • Active at night (answer)
   • Spinning backward
   • Found only at the poles

Words

• sidereal: measured by stars
• deflected: turned aside
• Coriolis: spin deflection
• refraction: light bending
• heliotrope: a flowering plant
• nocturnal: active at night