Fast and slow Earth changes
Use information from several sources to distinguish rapid Earth events, such as earthquake shaking, from gradual changes, such as mountain-range growth and long-term canyon carving
What a learner can do afterwards
- Give at least two examples of Earth changes that can happen rapidly, such as earthquake shaking, landslides, floods or the start of an eruption
- Give at least two examples of gradual Earth changes, such as mountain-range growth and a river carving a deep canyon over many years
- Use evidence from text, images, or video to support the distinction between fast and slow changes
1 · Read
Earth changes at different speeds. Erosion moves soil or rock pieces and can happen quickly during a storm. Earthquake shaking can happen in seconds or minutes. A landslide can move rock quickly. Lava can start flowing within minutes, but an eruption may continue much longer.
Some large changes build up over a long time. A river can carve a deep canyon by removing rock over thousands or millions of years. Many mountain ranges grow over millions of years as parts of Earth's outer layer push together. These are examples of gradual change.
Check the real time covered by evidence. A normal-speed video with time marks can show a rapid change. Time-lapse video speeds up events, so a short film may show a slow change. Dated height measurements showing small rises over many years can support gradual mountain-range growth.
Photos are taken at the start, 4 years later, and 4 more years later. Add the gaps: 4 + 4 = 8 years from first to last. Dates give the time span. The photos must also show what changed; dates alone do not prove slow change. A quick event could happen between two photo dates.
Some Earth changes happen quickly; others build up over many years. Check both the change and the real time covered by your evidence.
The lesson, questions and flashcards were written for this dataset.
The readings and flashcards were written for this dataset.
More to read
A change can start quickly
Earthquake shaking and landslides can change land suddenly. Lava may also begin flowing quickly during an eruption.
The start and the whole event are different things to measure. An eruption can continue long after lava first appears. Describe which action you mean and check the time given by the evidence.
Changes adding up
A river can remove rock during many separate flows. Over a long time, this can help carve a deep canyon. Many mountain ranges grow as parts of Earth's outer layer push together.
A storm can move soil quickly too. Erosion tells us material moved. More evidence is needed to describe its speed.
Checking the record
Earthquake damage describes effects on a place. Damage alone does not tell us how long the ground shook. A timed recording can provide evidence of how long the shaking lasted.
For slower changes, compare dated records from the same place. Check what they measure. A short video may speed up a long event, so check real time rather than film length.
2 · Watch
به انگلیسیTake it off screen
Where it sits
Learn first
Nothing; this is a starting point.
Optional connections
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.