5th grade-ch. 9 lesson 3 what is weathering
TRANSCRIPT
Ch. 9 Lesson 3
What is weathering?
Sugar cubes-Weathering activity1. Describe the appearance of the sugar cubes.2. Place the sugar cubes in the jar & shake 5 times.3. Pour the contents of the jar onto a piece of
paper separating the sugar cubes and the crumbs. (don't eat any of it !!!)
4. Describe any changes you notice in the sugar cubes.
5. Return the sugar cubes to the jar and shake another 5 times.
6. Again pour the contents onto a piece of paper separating the crumbs and the cubes.
7. Did the second shaking cause the cubes to look more worn?
8. Is the amount of crumbs greater than, the same as or less than the first shaking?
2 types of2 types ofweatheringweathering
mechanical chemical
mechanical weathering
• breaking of rock smaller pieces by forces:
•gravity
• water
• ice
ice wedging•water freezes in cracks of rock &
expands & forces rock to split
Rocks Change [01:13]
• plant roots
rate of mechanical weathering on rocks depends on:
1. type of materials in rock
2. conditions around it
sandstone granite
chemical weathering
• changes in rock by chemical processes
• raindrops absorb CO2 from air
makes carbonic acid makes caves
stalactites & stalagmites
The stalactite formed over the
bat before the bat
decayed.
Weathering [06:58]
soil• mixture of sediments :
– weathered rock
– decayed organisms
– gases from air
– water
parts of soil
topsoiltopsoil= fertile b/c large = fertile b/c large amt. decayed materialamt. decayed material
subsoilsubsoil= less decayed = less decayed materialmaterial
bedrockbedrock= nearly solid rock= nearly solid rock
sediments in soilsediments in soil