The greenhouse effect

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Energy flows as a share of incoming sunlight (NASA)

   Flow	Share of incoming sunlight
   Reflected to space	29%
   Absorbed by the atmosphere	23%
   Absorbed by the surface	48%
   Infrared up from the surface	117%
   Infrared back down to the surface	100%
   Infrared from the surface straight to space	12%
   Infrared from the atmosphere to space	59%

2. 1.

   Using the table, the surface sends up 117% and gets 100% back. What is the net upward infrared, by Bo's math (NASA)?

   • 1.17% of incoming sunlight
   • 17% of incoming sunlight
   • 59% of incoming sunlight
   • 217% of incoming sunlight
3. 2.

   Of a net 17% leaving the surface as infrared, about 12% escapes straight to space. How much is absorbed by the air, by Esme's math (NASA)?

   • About 29%
   • About 71%
   • About 5%
   • About 1.4%
4. 3.

   Using the table, about 12% escapes straight to space and 59% leaves from the atmosphere. What is the total leaving as infrared, by Jun's math?

   • About 29%
   • About 71%
   • About 117%
   • About 47%
5. 4.

   A molecule with infrared arrows going up and down. What do greenhouse gas molecules do after absorbing thermal infrared, by Kira's reading (NASA)?

   • Warm up and radiate infrared in all directions
   • Reflect each ray straight back down, like a mirror
   • Turn the infrared into visible light
   • Store the heat for good and stop radiating

6. Use this

   Sunlight arrows in, and infrared arrows going up, back down and out to space.

7. 5.

   Why is the surface warmer than sunlight alone would make it, by Luz's reading (NASA)?

   • The air keeps sunlight from leaving again
   • Back radiation from the atmosphere adds heat
   • The ground makes its own extra heat each day
   • Reflected sunlight lands twice on the ground
8. 6.

   NASA: the surface gets back radiation equal to 100% of incoming sunlight. Where does that heat come from, by Milo's reading?

   • Sunlight bouncing off the ozone layer
   • Heat rising from deep inside Earth's core
   • Infrared radiated down by the warmed atmosphere
   • Moonlight reflected back down to the ground

9. Use this

   Absorption bands for water vapor and CO₂, with a window near 10 micrometers.

10. 7.

    NASA: water vapor lets some infrared through a window. Around what wavelength is that window centered, by Noah's reading?

    • About 10 micrometers
    • About 1 micrometer
    • About 100 micrometers
    • About 0.5 micrometers
11. 8.

    NASA: CO₂ strongly absorbs infrared longer than about 12 to 13 micrometers. What does more CO₂ do to the window, by Pia's reading?

    • Opens it wider, so more heat escapes
    • Partly closes it, so less heat escapes
    • Blocks more sunlight from coming in
    • Leaves it unchanged, since water vapor controls it
12. 9.

    Why does adding CO₂ matter even though water vapor is the most abundant greenhouse gas, by Ren's reading (NASA)?

    • CO₂ absorbs wavelengths that water vapor lets through
    • CO₂ reflects incoming sunlight back to space
    • Water vapor does not absorb any infrared
    • CO₂ absorbs the same wavelengths, so it adds little

13. Table, Greenhouse gas levels (IPCC AR6; NOAA), with columns Gas, Level

    Carbon dioxide (CO₂), 2019, 410 ppm; Carbon dioxide, before about 1750, 280 ppm or less; Methane (CH₄), 2019, 1866 ppb; Nitrous oxide (N₂O), 2019, 332 ppb.

14. 10.

    Which two gases in the table are given in parts per billion, by Ari's reading?

    • Carbon dioxide and methane
    • Methane and nitrous oxide
    • Carbon dioxide and nitrous oxide
    • Oxygen and nitrogen