20-Year Map of Global Rainfall

This visualization from NASA shows global rainfall patterns over a 22-year span. It incorporates data from a combination of remote-sensing and ground-based sources.

Agricultural Runoff and the Gulf of Mexico Dead Zone

This video segment adapted from Big River: A King Corn Companion shows how agricultural chemicals from the Midwest that travel downstream in water runoff create a vast marine "dead zone" in the Gulf of Mexico.

Air Quality Index

In this interactive activity adapted from "Air Quality Index: A Guide to Air Quality and Your Health" by the U.S. EPA, learn about common pollutants in the air we breathe, their health effects, and how their levels are reported.

Anatomy of a Rover

In this interactive activity from NOVA, learn about the sophisticated scientific instruments on two identical robotic rovers that have explored Mars — Spirit and Opportunity.

Anatomy of a Tsunami

Using visual models and other graphics, this interactive activity from NOVA Online reveals details of the December 26, 2004 tsunami that collided with coasts around the Indian Ocean.

Anatomy of a Volcano

In this interactive activity from NOVA Online, explore the main features of the Nyiragongo volcano, located in the Democratic Republic of Congo, and learn what risks it poses to the 500,000 people who live in its shadow.

Antarctica: A Challenging Work Day

What happens when the ground under your feet is ice and it's moving? This video segment adapted from NOVA features some of the dangers faced by scientists conducting research in Antarctica.

Accessibility features: Caption

Antarctica: Sea Ice

This video segment adapted from NOVA uses microwave images to reveal how sea ice doubles the size of Antarctica each winter. Rare footage shows how sea ice crushed the famous ship Endurance in 1914.

Accessibility features: Caption

Antarctic Ecosystem

In contrast with its largely lifeless interior, the Antarctic coastal marine environment supports a vibrant and diverse ecosystem. Explore the region's living bounty in this interactive activity adapted from the Woods Hole Oceanographic Institution.

Antarctic Ice Movement: Part I

This video segment adapted from NOVA explains why ice sheets move. To find out how fast they move, scientists carve a tunnel through a glacier.

Accessibility features: Caption

Antarctic Ice Movement: Part II

Within Antarctic ice sheets are fast-moving streams of ice. This video segment adapted from NOVA hypothesizes about how ice streams are the result of warming at the end of the last ice age.

Accessibility features: Caption

Antarctic Ice: Sea Level Change

What would happen if a portion of the Antarctic Ice Sheet were to melt? This video segment adapted from NOVA uses animations to show the effect of a 6-meter sea-level rise on coastal cities across the world.

Accessibility features: Caption

Arctic Atlas

In this interactive atlas adapted from UNEP/GRID-Arendal, explore different environmental features of the Arctic. Select from a list of themes to customize your map, then zoom in to take a closer look at one of six featured regions.

Arctic Climate Perspectives

This video, adapted from material provided by the ECHO partners, describes how global climate change is affecting Barrow, Alaska.

Accessibility features: Audio Description, Caption

Arctic Ecosystem

Despite seemingly inhospitable conditions, the Arctic environment has a vibrant and diverse ecosystem. Explore the life that thrives in this region in this interactive activity adapted from the Woods Hole Oceanographic Institution.

Arctic Sea Ice Satellite Observations

In this interactive activity produced for Teachers' Domain, learn how Arctic sea ice has changed over the past 25 years in terms of maximum winter extent, concentration, and the timing of breakup each spring.

Arctic Tundra

This video segment from Wild Europe: "Wild Arctic" explores the struggle for survival in one of Earth's most extreme environments.

Accessibility features: Audio Description, Caption, Transcript

Atrazine Affects the Water Supply

In this video segment featuring live-action animation, adapted from Big River: A King Corn Companion, see how the agricultural pesticide atrazine impacts both crops and human health.

Accessibility features: Caption

Avalanche Town

The impact of natural disasters is made vivid in this video segment adapted from NOVA. A small town in Iceland, prepared for recurrent avalanches, is devastated when one takes a new and damaging path.

Accessibility features: Caption

Becoming a Fossil

This video segment describes how the Australopithecus afarensis skeleton known as Lucy could have been fossilized. Footage courtesy of NOVA: "In Search of Human Origins."

Accessibility features: Audio Description, Caption, Transcript