Science Quiz - Weathering and Soil

SV

What are the two main types of weathering?

physical and chemical

Weathering definition?

breakdown of rock and other substances at Earth’s surface

Erosion definition?

movement of sediment by water, wind, ice, gravity

What is mechanical weathering? Characteristics of it?

rock is physically broken into smaller pieces, works slowly, exposes more surface area to weathering

What are the specific types of mechanical weathering?

ice wedging - water expands when it freezes, allowing rock to crack/break

release of pressure - tectonic plates push rocks up from under surface, less pressure from things on top means that rock can start to flake off

living things - PLANTS AND ANIMALS! when plant roots grow they can split rock open, digging animals, woodpeckers

abrasion - grinding away of rock particles by other rock particles, usually carried away by wind, water, ice

What is chemical weathering? Characteristics of it?

breaks rocks down through chemical changes, faster than mechanical, produces rock particles w/ different chemical makeup, creates holes/soft spots in rocks

What are the specific types of chemical weathering?

water (a universal solvent) can dissolve rock
oxygen - o2+iron+h20 = oxidation

co2 - co2+h20 = carbonic acid

living organisms - plant roots produce weak acids (higher ph)

acid rain = gases produced from burning fossil fuels +water

What are the types of weathering we discussed in class (with the stations)?

water, abrasion, surface area, acid rain, carbon dioxide/carbonic acid

What is the rate of weathering affected by?

type of rock - igneous rocks weathers slower because they are stronger and all one rock, sedimentary rocks weather faster because they are made of many pieces of other rock cemented together and can easily come apart

amount of surface area - more surface area weathers faster

climate - hot climates speed up chemical weathering reactions. wet climates have more chemical weathering from water. cold climates have physical weathering (ice wedging) that cannot exist in warmer temps

What is plant litter?

dead plant material (leaves, etc)

How would sand samples differ from soil samples?

sand would be drier and a lighter color - less humus,

What is soil?

loose weathered material on Earth’s surface

What is humus?

dead organic matter

What type of soil has the closest to equal parts sand, silt, and clay? Why is this soil best for growing plants?

clay loam, it has all soil textures which holds the exact amount of moisture, air, and room for roots to grow

What are the 2 main types of organisms that affect the soil and some examples? How do they affect the soil?

Mixers - put air back into the soil, mix in water and nutrients (worms, ants, burrowing animals)
Decomposers - form humus, break down organic matter (bacteria, worms fungi)

Draw soil formation!

look in binder for answer!

Problems of very small (clay) vs very large (sand) particle sizes/textures?

clay - does not drain water well, does not have enough air, too compact for roots to grow easily

sand - drains water very quickly, dries out and is too loose for most roots to hold on to

What are some causes of soil degradation?

overfarming/monoculture
deforestation

overgrazing (overuse of land for animals)

urbanization (paving the soil keeps ground from absorbing water, causing runoff down the street)

What are some soil conservation methods and characteristics of them?

contour farming - plants rows perpendicular to slope (plowing along contours of hill instead of straight up and down)

crop rotation - planting different crops each year to maintain nutrients in soil since different crops take different nutrients from the soil

conservation plowing - also called no till farming, when crops are planted on top of old ones to keep soil covered

Name the largest to smallest particle sizes.

sand, silt, clay

What is soil?

loose, weathered material on e

What was the Dust Bowl?

1930s to 1940s environmental disaster in the Great Plains states caused by overfarming/drought

Draw the pie chart of soil composition/write the percentages!

water is 20 to 30%, air is 20 to 30%, rock particles and minerals are 45%, humus is 5%

What is the celsius-fahrenheit freezing point temp conversion? Boiling point conversion?

0 degrees C is 32 degrees F (freezing pt).

100 degrees C is 212 degrees F (boiling pt).

How does a region that experiences strong chemical weathering differ from a region that experiences strong mechanical weathering (in terms of climate)?

chemical - hot and wet, mechanical- cold and more frost