Rock Bottom
A tree root grows into a crack and slowly splits a rock apart. Is this mechanical or chemical weathering?
Mechanical weathering.
Soil contains rock particles, minerals, organic matter, air, and one other major ingredient. What is the other major ingredient?
Water.
Water, ice, wind, and gravity can all do this to sediment.
Move or erode it.
Wind removes loose sediment from the ground and carries it away. Which wind-erosion process is happening?
Deflation.
Wind carrying sand hits a large boulder and slows down. What process will most likely happen next?
Deposition.
Acidic water changes the minerals inside a rock. Why is this chemical weathering instead of mechanical weathering?
Because the rock’s minerals/composition are being changed.
A gardener wants soil with lots of decayed organic material and nutrients. Which soil horizon would probably be most useful?
Horizon A/topsoil.
A pile of loose rock suddenly begins moving downhill even though there is no river or wind nearby. What force is responsible?
Gravity (the hater).
Windblown sand repeatedly strikes a rock and scrapes its surface. Which process is happening?
Abrasion.
A pile of windblown sand begins forming behind an obstacle. What landform is developing?
Sand dune.
Two identical rocks sit outside. One is whole and one has been crushed into many pieces. Which will weather faster, and why?
The crushed rock, because it has more surface area exposed.
Scientists find a layer where minerals have collected below the topsoil. Which horizon are they examining?
Horizon B.
After a rainstorm, water, soil, and rock rush rapidly downhill together. Which type of mass movement occurred?
Mudflow.
Wind is carrying three particle sizes. Which will likely travel highest and farthest?
The smallest/fine particles.
Two dunes receive the same wind, but one has many plants growing on it. Predict which dune will move less and explain why.
The dune with plants, because roots can anchor the dune in place.
One rock is in a warm, rainy climate and another is in a cold, dry climate. Which should weather faster?
The rock in the warm, wet climate.
A student digs down until the soil contains mostly partly weathered rock. Which horizon has the student reached?
Horizon C.
True or False: Creeps move very quickly, while landslides move very, very slowly.
False. The opposite is true. Creeps move slowly, while landslides move very quickly.
Predict how each moves: fine particles, medium particles, large particles.
Fine = carried through the air; medium = skip/bounce; large = slide/roll.
Scientists notice that two dunes have different shapes and sizes. Give two factors from the study guide that could explain the difference.
Wind direction, amount of sand, or presence of plants.
A rock breaks apart, the pieces are carried down a river, and later settle at the riverbank. Identify the three processes in order.
deposition - weathering - erosion
Weathering → erosion → deposition.
Explain why humus is important to soil rather than simply calling it “dead stuff.”
It is decayed organic material that adds nutrients to the soil.
A large section of rock and soil suddenly moves downhill. It isn’t flowing like a mudflow and it isn’t slowly creeping. What type of mass movement is happening?
Slump.
A windstorm gets stronger. How will this affect the size of sediment the wind can move?
The stronger wind can move larger particles.
Farmers discover a thick deposit of fine sediment that is smaller than sand but larger than clay. Why might they be excited?
It is probably loess, which can create nutrient-rich soil and valuable farmland.
A rock has been broken into many small pieces, but none of the pieces have moved anywhere yet. Which process has happened, and which two have not happened yet?
Weathering has happened. Erosion and deposition have not
A soil sample has very little humus but lots of collected minerals. Which horizon is it most likely from?
B Horizon.
A hillside moves so slowly that the movement is almost impossible to notice from day to day. What type of mass movement is occurring?
Creep
DOUBLE JEOPARDY:
A strong wind begins blowing across a dry area.
It picks up fine sediment, causes larger grains to bounce along the ground, and carries the smallest particles far away. Eventually the wind reaches a group of plants and slows down.
Predict what happens next and name TWO landforms or deposits that could eventually form because of wind deposition.
The wind drops sediment because it slows down or encounters an obstacle. Sand may build up into a sand dune, while very fine wind-deposited sediment can form loess deposits.
“A sand dune is an example of erosion because wind moved the sand there.” Explain what is wrong with the student's reasoning.
Wind eroded the sand while transporting it, but the dune itself forms when the sand is deposited.