Orbital cycles and ice ages

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Earth's orbit with January and July marked. A classmate says summer comes when Earth is closest to the Sun. Which reply fits NASA, by Esme's reading?

   • Correct; closest means summer everywhere
   • No; seasons come from the wobble alone
   • No; Earth is closest around January 3, in northern winter, and tilt sets seasons
   • Correct; the farthest point comes in winter

2. Read this first

   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

3. 2.

   A student says ice ages come and go over a few centuries. Which reply fits NASA, by Jun's reading?

   • No; for 800,000 years they have cycled about every 100,000 years
   • No; they come about once in each 10 million years, far apart in time
   • Correct; each lasts about 100 years
   • Correct; they follow the 11-year sunspot cycle
4. 3.

   Earth tilted more and less beside the Sun. A student says a bigger tilt helps ice sheets grow. Which reply fits NASA, by Kira's reading?

   • No; larger tilt favors melting, and a smaller tilt lets ice build
   • No; ice grows when Earth is farthest from the Sun in northern June
   • Correct; a big tilt means cold summers
   • Correct; tilt has no effect on ice

5. Use this

   A timeline divided into equal cycles.

7. 4.

   NASA: in about 13,000 years precession will flip which hemisphere has more extreme seasons. What fraction of the 25,771.5-year cycle is that, by Luz's math?

   • About a tenth
   • About twice
   • About half
   • About a quarter
8. 5.

   Hays and colleagues studied 450,000 years (NASA). About how many 41,000-year tilt cycles fit in that span, by Milo's math?

   Use the picture in question 4.

   • About 11
   • About 1.1
   • About 4.5
   • About 110

9. 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

10. 6.

    Using the EPICA table, what is the range from the table's coldest value (−9.4 °C) to its warmest (+3.4 °C), by Noah's math?

    • About 128 °C
    • About 3.4 °C, the warmest value
    • About 6 °C
    • About 12.8 °C
11. 7.

    Four evidence cards, labeled A to D. Which evidence best supports Milankovitch's idea, by Pia's reading (NASA)?

    • One cold winter after a far aphelion
    • Ice ages repeating each century
    • Tilt staying fixed for a million years while the ice sheets came and went
    • Sediment and ice cores show climate swings timed with orbital cycles

12. 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

13. 8.

    Model data: cold periods come every 100,000 years for the last 800,000 years and every 41,000 years before that. Which cycles match each part, by Ren's reading?

    • Orbit shape recently; tilt earlier
    • Tilt recently; orbit shape earlier
    • The yearly orbit for both parts
    • The 26,000-year wobble for both parts
14. 9.

    Orbit shape, tilt and wobble, each with its cycle. Which summary of Milankovitch cycles fits NASA, by Zee's reading?

    • They change the Sun's brightness each year
    • Orbit shape (about 100,000 years), tilt (41,000) and wobble (26,000) shift sunlight
    • They set the seasons by distance
    • Orbit shape (26,000), tilt (100,000) and wobble (41,000)

15. 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

16. 10.

    Which summary of the EPICA Dome C record fits NOAA, by Bo's reading?

    • Glacials about 90 °C colder
    • About 800 years of steady temperature
    • Glacials warmer than interglacials
    • About 800,000 years of Antarctic temperature, with glacials near −9 °C