Weathering and Erosion Video Questions &Answers Eric Angat Teacher

Weathering and Erosion

1. Why is the Yosemite valley shaped like a half dome? Was it a whole dome before? What changed it?

Yosemite Valley was a whole dome shaped mountain before but weathering and erosion changed it into half dome.

http://www.nps.gov/yose/planyourvisit/halfdome.htm

2. What are landforms?

Landform refers to the shape of the land like mountains and valleys.

http://ccs.clarityconnect.com/NRiggs/Landforms.html

3. What can instantly change the surface of Earth?

Eruptions of volcanoes, earthquakes, and landslide can instantly change the shape of Earth.

4. What are the processes that slowly change the surface of Earth?

Weathering and erosion

5. What is weathering?

Weathering breaks rocks and turn them to sediments.

http://www.nps.gov/yose/planyourvisit/halfdome.htm

6. What are the causes or agents of weathering?

Water, ice, wind, temperature, living things

http://www.nps.gov/yose/planyourvisit/halfdome.htm

7. Why is water considered as the

most powerful agent of

weathering?

The physical forms and chemical properties of water can easily break rocks.

http://fphoto.photoshelter.com/image/I0000_fmfxY9ukMU

8. How can water split rocks apart? ( freezing and thawing )

Frost wedging is the breaking of rock by the freezing of water. Water expands by 9% when it is frozen.

http://www.answers.com/Q/Where_does_frost_wedging_occur

9. Why are the rocks in stream smooth and rounded?

Rocks in a stream roll because of the flowing water, this process makes them smooth and rounded.

http://motherhood.modernmom.com/putting-river-rocks-around-bushes 13761.html

10. How can acids affect rocks? Acid causes chemical weathering on rocks.

Acids can dissolve the minerals in rocks thus breaking the rock.

http://imgarcade.com/1/carbonation-chemical-weathering/

11. How can plants break rocks? Plants are agents of weathering.

Plant roots can grow in cracks in rocks making the cracks bigger and bigger until the rock breaks.

http://miftahulxiimm1.blogspot.com/2012/10/power-exogenous.html

12. How can wind shape or break rocks? Wind is an agent of weathering and erosion.

Wind can blow sediments towards rocks and shape them.

http://biocircuits.ucsd.edu/outreach/?p=714

13. How can temperature changes break rocks? Materials expand when heated and contracts when cooled.

Rocks expand when it is warm and contract when it is cold. This expansion and contraction break rocks.

http://1e-geography.blogspot.ca/

14. What happens to the broken rocks?

Erosion happens when sediments are moved from one place to another.

15. What are the agents of erosion?

Flowing water, wind, ice, and gravity are the agents of erosion.

16. What is creep and what causes it?

A creep is the slow movement of land downhill. It is caused by gravity.

17. What is mudslide and what causes it?

Mudslide happens when moving water erodes soil and mud down slope. It is caused by moving water and gravity.

Mudslide and landslide avalanche Lahar Rapid movement of

rocks and sediments

on a slope.

Rapid movement of

snow, ice, and rocks

on a slope.

Rapid movement of

volcanic materials

on a slope.

18. What is glacier and how does it shape the surface of Earth?

Glacier is moving ice along a slope. As the ice moves it scrapes and transports rocks and soil.

19. What causes the ripples on sand and sand dunes in deserts?

Wind causes ripples on sand. Dunes are formed when the sand is deposited by the wind.

20. Why are people considered as agents of weathering and erosion?

Human being break and move rocks and sediments to build structures.

21. What is terracing and how does it help farmers?

Terracing is making steps on the sides of farmlands. This prevents the topsoil from being eroded.

22. What is weathering?

Weathering breaks rocks into sediments

23. What is erosion?

Erosion carries sediments away.

24. What is deposition? How does it form sand dunes and delta?

Deposition is the dropping off of eroded rocks. Deposition form sand dunes in the desert and delta at the mouth of the river.

Define the following:

Physical weathering Breaking rocks without changing their composition.

Examples: frost wedging, rolling rocks due to gravity

Define the following:

Chemical weathering Breaking rock due to decomposition, the composition of the rock changes.

Example: acid breaking rocks

The chemical weathering of limestone, or carbonation, occurs when the rock is attacked by rainwater. The chemical equation for this process is CaCO 3+ H 2CO 3 = Ca(HCO 3) 2, Limestone + Carbonic acid (rainwater) = Calcium Bicarbonate (soluble limestone).