The Greenhouse Effect
Interactive simulation of the greenhouse effect
Description
Textbooks cover the greenhouse effect in a sentence — greenhouse gases absorb infrared radiation and the surface warms — which students memorize while still having no feel for why infrared rather than visible light, or how much a change in concentration actually moves the temperature. This PhET simulation puts the process on screen: drag the greenhouse gas concentration slider and the share of infrared sent back to the surface changes while the thermometer reading rises or falls in real time, with sunlight passing through, the surface radiating infrared, and that infrared being intercepted all visible at once.
Three modes are included: Waves shows energy flow as waves, Photons draws radiation as individual photons so absorption and re-emission are traceable, and Layer Model abstracts the atmosphere into layers for more quantitative work. Atmospheric composition can be switched between periods — ice age, 1750, today — to see what the same physics yields at different concentrations.
PhET Interactive Simulations is a project of the University of Colorado Boulder. The simulations are free, written in HTML5, run in a browser, and can be downloaded as a single HTML file for offline use.
Adjustable concentration: a continuous slider for greenhouse gas concentration plus presets for ice age, 1750 and modern atmospheres, for comparing the same model across conditions.
Live temperature feedback: a surface thermometer responds as concentration changes, so the relationship shows itself rather than needing to be asserted.
Three representations: Waves for energy flow, Photons for individual absorption and re-emission events, and Layer Model for quantitative layered analysis — three views of one phenomenon.
Energy balance: an optional panel shows energy entering and leaving the system, framing warming as an imbalance rather than a vague process.
Clouds: a cloud can be added to observe its effect on reflection and absorption, bringing another variable into play.
Runs in a browser: HTML5 with no plugin required, working on desktop and tablet browsers.
Works offline: the single HTML file can be saved locally for classrooms without reliable internet.
Free and open: produced by the PhET project at the University of Colorado Boulder, free for teaching and self-study, with the interface available in many languages.
Three modes are included: Waves shows energy flow as waves, Photons draws radiation as individual photons so absorption and re-emission are traceable, and Layer Model abstracts the atmosphere into layers for more quantitative work. Atmospheric composition can be switched between periods — ice age, 1750, today — to see what the same physics yields at different concentrations.
PhET Interactive Simulations is a project of the University of Colorado Boulder. The simulations are free, written in HTML5, run in a browser, and can be downloaded as a single HTML file for offline use.
Features
Adjustable concentration: a continuous slider for greenhouse gas concentration plus presets for ice age, 1750 and modern atmospheres, for comparing the same model across conditions.
Live temperature feedback: a surface thermometer responds as concentration changes, so the relationship shows itself rather than needing to be asserted.
Three representations: Waves for energy flow, Photons for individual absorption and re-emission events, and Layer Model for quantitative layered analysis — three views of one phenomenon.
Energy balance: an optional panel shows energy entering and leaving the system, framing warming as an imbalance rather than a vague process.
Clouds: a cloud can be added to observe its effect on reflection and absorption, bringing another variable into play.
Runs in a browser: HTML5 with no plugin required, working on desktop and tablet browsers.
Works offline: the single HTML file can be saved locally for classrooms without reliable internet.
Free and open: produced by the PhET project at the University of Colorado Boulder, free for teaching and self-study, with the interface available in many languages.
