Thermal Energy

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Same principle behind dressing in coats and sweaters to keep warm

Warmer air is trapped close to our bodies, reducing energy loss by convection and conduction

Slide 24

Global Warming

Analogous to a greenhouse

Visible light and short-wavelength infrared radiation are absorbed by contents of greenhouse, resulting in the emission of longer-wavelength infrared radiation (IR)

Longer-wavelength IR absorbed by glass

Glass emits IR, half of which is emitted back inside the greenhouse

Convection currents are inhibited by the glass (although this is not mirrored in Earth’s atmosphere)

Earth’s atmosphere fills role of glass roof in greenhouse

“Greenhouse gasses” like CO2 are particularly good absorbers of IR

More greenhouse gasses in the atmosphere means more IR is absorbed and Earth’s surface becomes warmer