Audio description example
This NASA explainer is a hard case: the narrator speaks almost without pause, while the picture shows facts the narration never says, like the scientist's name and the numbers on a climate chart. Standard description would have only two short gaps to work with, so we used extended description.
What the descriptions add
| Time | Type | Description |
|---|---|---|
| 0:00 | Standard | Title: How do we know what Earth's climate was like long ago? |
| 0:12 | Extended | NASA climate scientist Doctor Gavin Schmidt speaks from his home office. Then: a red rock wall, and sunlight rippling over stones in shallow water. |
| 0:23 | Extended | Footage: rugged cliffs, a green mountain valley, a large lone boulder on a rocky shore, a glacier, a sunset over the sea, and a rocky island wrapped in mist. |
| 0:37 | Extended | An ice core lies in a tray. An animated cross-section of the Greenland ice sheet marks the Camp Century ice core, with layers labeled by age. Then an iceberg, a magnifying loupe over a fossil shell, and tiny colorful shells on a beach. |
| 0:47 | Extended | Geologists hike a rocky slope. Then two globes compare temperatures. Left, the Cretaceous, 110 million years ago: no ice, seas 330 feet higher, carbon dioxide 1000 parts per million, average 80 degrees Fahrenheit. Right, today: ice sheets, 404 parts per million, 59 degrees. |
| 1:00 | Extended | Animations: canyon terrain, glowing plate boundaries splitting Earth's crust, a globe labeled Axial Precession wobbling on its axis, and an asteroid striking Earth in a bright flash. |
| 1:06 | Extended | A world temperature map steps from the early 1990s to 2016 through 2020, the Arctic turning deep red. Then a map of Antarctica, and a satellite map of ice height change since 2019. |
| 1:14 | Extended | Doctor Schmidt again, then people standing on a rocky outcrop in a city park, skyscrapers behind them. Closing graphics and the NASA logo follow. |
Why these choices
- Name the speaker. The on-screen caption identifies Dr. Schmidt, but the audio never does.
- Read the numbers. The globe comparison carries the key facts of the video only as on-screen text.
- Pause at sentence ends. Extended description never cuts the narrator off mid-sentence.
- Stay objective. We describe what is shown, not what it means.
Original video: How Do We Know What Earth's Climate Was Like Long Ago?, NASA Goddard Scientific Visualization Studio (public domain). NASA does not endorse this service.