Constructive and
Destructive Processes
Ms. Meskie
Ms. Krutty
Check This Out!
Volcanoes
Stations
 Station 1
 Page 1, question 1: What do you think will happen
when water is poured over the “hill”?
 Station 2
 Page 2, question 9: What will happen when you rub
sandpaper over the limestone?
 Station 3
 Page 2, question 12: What is the effect of water on
limestone?
 Page 2, question 13: What is the effect of the acid on
limestone?
Constructive Processes
 Build the earth up
Destructive Processes
 Destroy or break down part
of the earth
Constructive or
Destructive?
Volcanoes
 Constructive process
 Builds up land around the volcano
 1943 in farmer’s field in Mexico – built a mountain
in 9 years
 1964 off coast of Iceland – now a large island
Constructive or
Destructive?
Plate Tectonics and
Mountain-Building
 Constructive Process
 Oceanic plate more dense than continental plate
 Oceanic plate pushed under continental plate,
continental plate crumples
 Two plates collide and both are pushed up and
crumpled
 Video 1
 Video 2
Plate Tectonics and
Mountain-Building
 Subduction – the process that takes place at
convergent boundaries in which one tectonic plate
sinks under another into the Earth’s mantle
because it is more dense than the other
 Density – mass per unit volume
 (Density=Mass/Volume)
 Orogeny (uplift) – a process in which the forces
produced by convergent tectonic plates produce
mountains
Constructive or
Destructive?
Weathering and Erosion
 Destructive Process
 Weathering 1st to weaken the rock, erosion 2nd to
break it away
 2 kinds of weathering:
 Mechanical – breaks down rocks
 Wind
 Water
 Plants
 Animals
 Chemical – changes rocks into something new
 Chemicals (Ex. Acid rain)
Weathering and Erosion
 Weathering – the breaking down of rocks, soil, and
minerals through contact with the atmosphere
 In-Situ – with no movement; takes place in that
spot
 Erosion – movement of rocks and minerals by
agents such as ice, water, wind, and gravity
 Hydration – a process in which a rock takes in
water, and the increased volume creates stress in
the rock, breaking it up
Weathering and Erosion
 Carbonation – a process in which carbon dioxide
mixes with rain, making the rain acidic, which in
turn breaks down certain types of rocks
 Oxidation (rusting) – a process in which water and
oxygen mix and weaken the rock (this occurs
mostly with metal ores)
Weathering and Erosion
 Plant’s roots have
grown into the rock
 Causes some of the
rock to break apart
 Mechanical or
chemical weathering?
Weathering and Erosion
 Iron in rock reacts
with oxygen in air
 Creates rust and
weakens the rock
 Mechanical or
chemical weathering?
Weathering and Erosion
 Erosion




Carries away weathered rock
Wind blows dust off side of cliff
Silt carried downstream by river
Rocks fall off side of cliff due to gravity
Wind
Water
Ice
What happens to the
weathered rock that is
carried away?
Deposition
 Sand and pieces of rock are deposited by water,
wind, or ice as a result of erosion
 Constructive or destructive?
Summary
Constructive
 Volcanoes
 Plate Tectonics and
Mountain-building
 Subduction
 Density
 Orogeny
 Deposition
Destructive
 Weathering and Erosion






Weathering
In-Situ
Erosion
Hydration
Carbonation
Oxidation
Station 1
2. Observations
3. Which substance moved first? Next? Last?
4. Did the size of the particles affect the rate of erosion?
5. Would the amount of water affect the rate of erosion?
6. Would the hardness of the rain affect the rate of
erosion?
7. If you wanted to control erosion on a hill, what type of
particles would be best to use?
8. What do you think happens to the surfaces of
mountains that experience large amounts of rainfall?
Station 2
10. Observations
11. How is rubbing sandpaper across a rock like
windblown sand hitting a rock?
Station 3
14. Observations
15. What is the effect of water on limestone?
16. What is the effect of the acid on limestone?
17. How long do you think it will take for the acid to
completely dissolve the limestone?
18. How might this process occur in nature?
19. Is this an example of mechanical or chemical
weathering?
Post-Lab Quiz
1. What is the difference between a constructive
process and a destructive process?
2. Carbon dioxide in the air can combine with rain to
create acid rain. When this acid rain hits
limestone, it weakens the limestone through a
process called carbonation. Would this be
considered mechanical or chemical weathering?
Post-Lab Quiz
3. Which process caused this change in landscape?
Post-Lab Quiz
4. Which process caused this change in landscape?
Post-Lab Quiz
5. Which process caused this change in landscape?
Post-Lab Quiz
6. Which process caused this change in landscape?