Layers of the atmosphere

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Layer bases (about, NOAA)

   Layer	Starts at (km)
   Troposphere	0
   Stratosphere	11
   Mesosphere	50
   Thermosphere	85

2. 1.

   A balloon rises to 30 km. Ari reads the table. Which layer is it in, and which comes next?

   • Stratosphere now, troposphere next
   • Troposphere now, stratosphere next
   • Mesosphere now, thermosphere next
   • Stratosphere now, mesosphere next

3. US Standard Atmosphere

   Height (km)	Temperature (°C)	Pressure (hPa)
   0	15.0	1,013.25
   11	-56.5	226.32
   47	-2.5	1.11
   71	-58.5	0.04

4. 2.

   Bo reads four heights from the table. Which layer lies between 11 and 47 km?

   • The troposphere, where temperature rises with height
   • The mesosphere, where temperature rises with height
   • The stratosphere, where temperature rises with height
   • The thermosphere, where temperature rises with height
5. 3.

   Kira climbs from the ground to 100 km. The layers change at about 11, 50 and 85 km. How many boundaries are crossed?

   • Two, at about 11 and 85 km
   • Three, at about 11, 50 and 85 km
   • Three, at about 11, 30 and 60 km
   • Four, at about 11, 50, 85 and 100 km

6. US Standard Atmosphere

   Height (km)	Temperature (°C)	Pressure (hPa)
   0	15.0	1,013.25
   11	-56.5	226.32
   20	-56.5	54.75
   32	-44.5	8.68
   47	-2.5	1.11
   51	-2.5	0.67
   71	-58.5	0.04

7. 4.

   Luz scans all seven rows. At which height is the air coldest, and in which layer?

   • 11 km, in the troposphere
   • 71 km, in the thermosphere
   • 20 km, in the stratosphere
   • 71 km, in the mesosphere
8. 5.

   Temperature rises with height through the stratosphere. What does Milo say heats the air there?

   • Ozone absorbs ultraviolet light and warms the air
   • Clouds in the stratosphere release heat as they form
   • The layer is closer to the Sun than the layers below it
   • Warm air rising from the ground heats it directly

9. Four events and their heights (example)

   Event	Height (km)
   Jet airliner cruising	11
   Weather balloon bursting	30
   Meteor glowing	80
   Space station orbiting	400

10. 6.

    Noah sorts the events by layer. Which event happens in the mesosphere (about 50 to 85 km)?

    • The meteor glowing at 80 km
    • The jet airliner cruising at 11 km
    • The space station orbiting at 400 km
    • The weather balloon bursting at 30 km

11. Ozone by height (example data)

    Height (km)	Ozone (ppm)
    10	0.3
    25	7
    40	5

12. 7.

    Pia finds where ozone is greatest. Which layer holds the most ozone?

    • The troposphere, where ozone peaks near 10 km
    • The mesosphere, where ozone peaks near 40 km
    • The stratosphere, where ozone peaks near 25 km
    • The thermosphere, where ozone peaks near 25 km

13. US Standard Atmosphere

    Height (km)	Temperature (°C)	Pressure (hPa)
    0	15.0	1,013.25
    11	-56.5	226.32

14. 8.

    Temperature falls from 15 °C to −56.5 °C in the first 11 km. Ren explains why storms stay in that layer. Which reason fits?

    • Pressure rises with height, which pushes clouds back toward the ground
    • Ozone near 11 km heats the air and drives the storms
    • Warm air near the ground rises and mixes with the colder air above it
    • Warm air above the ground sinks and mixes with the colder air below it

15. Dry air by volume (NOAA)

    Gas	Share (%)
    Nitrogen	78.08
    Oxygen	20.95
    Argon	0.93
    Carbon dioxide	0.04

16. 9.

    Tala adds up nitrogen and oxygen. About what share of dry air is neither one?

    • About 0.04%, mostly carbon dioxide
    • About 21%, mostly oxygen
    • About 22%, mostly argon
    • About 1%, mostly argon

17. Use this

    Oxygen is 20.95% of dry air at every height shown. Pressure at 11 km is 226.32 hPa. Partial pressure of oxygen = share × pressure.

18. 10.

    Zee works out how much of the pressure at 11 km is oxygen. What is it?

    • About 47 hPa, because the share stays near 21% while the pressure falls
    • About 4.7 hPa, because the share drops to 2.1% at 11 km
    • About 226 hPa, because the whole of the air at 11 km is oxygen
    • About 212 hPa, because 21% of the ground pressure is still there