The Greenhouse Effect: How greenhouse gases like CO2 and CH4 trap heat and warm the Earth's surface and lower atmosphere.

Let's solve the fill-in-the-blank passage about the greenhouse effect using the provided diagram and word bank.

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Passage with blanks:

> Certain gases, including ________ (CO₂) and ________ (CH₄), are transparent to most of the ________ of light arriving from the sun but are relatively opaque to ________ or heat ________; thus, energy passes through the Earth's atmosphere on arrival, is converted to heat by absorption at the surface and in the ________, and is not easily re-________ into space.

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Word Bank:

- atmosphere
- carbon dioxide
- infrared
- methane
- radiated
- radiation
- wavelengths

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Step-by-step reasoning:

1. First blank: "Certain gases, including ________ (CO₂)"
→ CO₂ stands for carbon dioxide, so the first blank is carbon dioxide.

2. Second blank: "and ________ (CH₄)"
→ CH₄ is methane, so the second blank is methane.

3. Third blank: "transparent to most of the ________ of light arriving from the sun"
→ The Sun emits light across various wavelengths, including visible light and ultraviolet. Greenhouse gases are transparent to shorter wavelengths (like visible light). So this blank is wavelengths.

4. Fourth blank: "but are relatively opaque to ________ or heat ________"
→ The Earth emits infrared radiation (heat). Greenhouse gases absorb this infrared radiation. So the fourth blank is infrared.

5. Fifth blank: "or heat ________"
→ This refers to radiation – specifically, infrared radiation is also called heat radiation. So the fifth blank is radiation.

6. Sixth blank: "absorption at the surface and in the ________"
→ The atmosphere absorbs some of the infrared radiation too. So this is the atmosphere.

7. Seventh blank: "is not easily re-________ into space"
→ The absorbed energy is re-emitted as radiation, but it’s not easily re-radiated back into space. So this blank is radiated.

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✔ Final Filled-In Passage:

> Certain gases, including carbon dioxide (CO₂) and methane (CH₄), are transparent to most of the wavelengths of light arriving from the sun but are relatively opaque to infrared or heat radiation; thus, energy passes through the Earth's atmosphere on arrival, is converted to heat by absorption at the surface and in the atmosphere, and is not easily re-radiated into space.

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🔍 Explanation:

This describes the greenhouse effect:
- Solar radiation (mostly visible light) passes through the atmosphere.
- The Earth absorbs this energy and warms up.
- The warm Earth emits infrared radiation (heat).
- Greenhouse gases like CO₂ and CH₄ trap some of this infrared radiation, re-emitting it in all directions, warming the surface and lower atmosphere.
- This process keeps Earth warm enough to support life, but excess greenhouse gases enhance it, leading to global warming.

✔ The correct answers are:
1. carbon dioxide
2. methane
3. wavelengths
4. infrared
5. radiation
6. atmosphere
7. radiated