Greenhouse Gas Science
Describe the electromagnetic spectrum and distinguish between short-wave solar radiation and long-wave infrared radiation emitted by Earth; explain how greenhouse gas molecules (CO2, CH4, N2O, H2O) absorb and re-emit infrared through molecular vibration while O2 and N2 do not; distinguish the natural greenhouse effect (which makes Earth habitable) from the enhanced greenhouse effect driven by human emissions; evaluate the relative potency of different greenhouse gases
Lesson
Set out your lesson
“Visible light is one part of electromagnetic radiation. The Sun supplies mainly shorter-wavelength energy; Earth emits longer-wave infrared. An electric dipole is a separation of positive and negative charge. N2 and O2 each contain two identical atoms. Their ordinary stretching keeps the charge distribution symmetric. It lacks the changing electric dipole needed for strong direct thermal-infrared absorption. CO2 has infrared-active bends and asymmetric stretching that change its electric dipole. CO2, CH4, N2O and H2O absorb in relevant infrared bands. Ordinary N2 and O2 are weak direct absorbers of Earth's thermal infrared, not molecules incapable of vibrating. Safety: No chemicals, fuel, heat or infrared devices. Cards are models, not measurements. Stop: Stop at the paper mechanism. No gas generation, lamps, spectroscopy, jars, or molecular experiment.”
Bring to the table
- Paper
- Pencil
- Six torn paper cards
Extra for the adult
Worked example. A CO2 bend changes its electric dipole; ordinary N2/O2 stretching keeps a symmetric charge pattern. That difference permits strong direct infrared interaction in relevant CO2 bands, not in ordinary N2/O2 stretching. N2 and O2 can still vibrate. In the supplied equal-mass, 100-year comparison, methane has value 28 relative to CO2's 1; this is not a ratio of their total warming contributions.
Optional challenge. Explain why changing the comparison horizon can change methane’s relative value.
What to notice. Keep diagrams, the molecular charge comparison and the gas ranking. Note adult help with formulas, vocabulary, ranking or interpretation.
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Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
PhET Interactive Simulations · Practice link — not the full lesson
Greenhouse Effect
Before you open · source notes
Greenhouse Effect supports hands-on exploration for Greenhouse Gas Science. Not every lab worksheet.
Free interactive page, no sign-in required for the tested path.
Before you openAsk the learner what they changed in the sim or page and what they observed.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public PhET Interactive Simulations page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.
PhET Interactive Simulations. “Greenhouse Effect.” External page; Gakuva does not copy, host, embed, or redistribute materials.
Unknown — link only
Check understanding
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“Can your child explain, in terms of light and energy, why CO2 in the atmosphere traps heat but nitrogen and oxygen — which make up most of the air — don't? What's physically different about CO2 molecules?”
Curriculum record
- Type
- Conceptual
- Subject
- Science
- Domain
- Weather & Climate
- Age range
- Ages 11–12