Orbital cycles and ice ages

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Three dials

   Orbit shape, tilt and wobble, each with its cycle.

2. 1.

   About how long is the tilt (obliquity) cycle, by Bo's reading (NASA)?

   • About 41,000 years
   • About 100,000 years
   • About 26,000 years
   • About 1 year
3. 2.

   About how long is the axial wobble (precession) cycle, by Kira's reading (NASA)?

   • About 100,000 years
   • About 26,000 years
   • About 26 years
   • About 41,000 years
4. 3.

   Earth tilted more and less beside the Sun. What is obliquity, by Jun's reading (NASA)?

   • The direction the wobble points
   • The tilt of Earth's axis relative to its orbit
   • The shape of the orbit
   • Earth's distance from the Sun
5. 4.

   Earth's orbit with January and July marked. NASA: Earth is closest to the Sun around January 3. Why are northern winters cold anyway, by Luz's reading?

   • The tilt has no effect on seasons
   • Distance sets the seasons
   • The Northern Hemisphere is tilted away from the Sun then
   • Earth is farthest from the Sun in January
6. 5.

   Earth tilted more and less beside the Sun. NASA: what does a larger tilt do to the seasons, by Milo's reading?

   • It makes them milder
   • It makes the year longer
   • It has no effect
   • It makes them more extreme

7. EPICA Dome C temperature record (NOAA NCEI)

   Years ago	Temperature vs last 1,000 years
   20,000	−9.4 °C
   128,000	+3.4 °C
   140,000	−9.1 °C
   410,000	+1.6 °C
   800,000	−8.9 °C

8. 6.

   Over the past 800,000 years, about how long has each ice-age cycle lasted, by Noah's reading (NASA)?

   • About 1,000 years
   • About 10 million years
   • About 100,000 years
   • About 100 years
9. 7.

   NASA: as ice cover grows, it reflects more of the Sun's energy. What does that do, by Pia's reading?

   • It has no effect on temperature
   • It promotes further cooling
   • It warms Earth
   • It speeds up Earth's orbit

10. EPICA Dome C temperature record (NOAA NCEI)

    Years ago	Temperature vs last 1,000 years
    20,000	−9.4 °C
    128,000	+3.4 °C
    140,000	−9.1 °C
    410,000	+1.6 °C
    800,000	−8.9 °C

11. 8.

    Using the EPICA table, how did Antarctica 20,000 years ago compare with the last 1,000 years, by Tala's reading?

    • About 94 °C colder
    • About the same
    • About 9.4 °C warmer
    • About 9.4 °C colder
12. 9.

    Which time in the EPICA table was warmer than the last 1,000 years, by Zee's reading?

    • 140,000 years ago
    • 20,000 years ago
    • 800,000 years ago
    • 128,000 years ago
13. 10.

    How far back does the EPICA Dome C ice-core record reach, by Esme's reading (NOAA)?

    • About 8,000 years
    • About 80 million years
    • About 800 years
    • About 800,000 years