https://padlet.com/2040073/vbi453aipdjb Honors Earth Science en-us 2017-11-03 18:34:07 UTC 2017-11-06 23:52:19 UTC hello@padlet.com 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203437964

Sand dunes form when wind blows sand grains into a sheltered area behind a barrier. As the grains of sand accumulate, dunes are created.]]> 2017-11-03 18:35:43 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203437964 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203438032

Hoodoos are formed by frost wedging and weather (mostly rain). Frozen water expands and slowly enlarges cracks, making them wider. After that, rain further erodes and sculpts them.]]> 2017-11-03 18:35:52 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203438032 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203438190

If a cave is formed in a headland (a slice of land that stretches from a coastline into the sea), eventually it may break through to the other side, creating an arch. Alternatively, arches can be formed over time when parallel fractures in surface rock erode creating "fins." Eventually the fins are completely worn through and arches are made]]> 2017-11-03 18:36:14 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203438190 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203438464

Frost wedging causes "talus" (large piles of broken rock fragment) to break apart and accumulate at the foot of a mountain.]]> 2017-11-03 18:36:48 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203438464 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203438999

Rivers and wind gradually erode the land between two slopes (usually mountains) over time and form valleys that appear to be in the shape of a "V."]]> 2017-11-03 18:38:02 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203438999 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203439132

When moving water in a stream wears down the outer banks and widens the valley a meandering stream is formed. The inner part of the river has less energy and thus deposits silt to the outside. ]]> 2017-11-03 18:38:19 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203439132 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203439258

A meander will become very curved after a long period of time. The neck eventually becomes narrower. Then, during a flood, the water will cut through the neck and will form an Ox-Bow Lake.]]> 2017-11-03 18:38:36 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203439258 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203439331

Soluble bedrock is exposed and gradually worn down over time, creating a sinkhole.]]> 2017-11-03 18:38:44 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203439331 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203439434

Rainwater picks up carbon dioxide from the air and seeps through the soil turning it into a weak acid. This slowly dissolves the limestone along fractures, some of which become enlarged enough to form caves.]]> 2017-11-03 18:38:58 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203439434 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203439580

Stalactites form when calcium bicarbonate from limestone rock dissolves into water. The water drips from the ceiling of a cave and as it comes in contact with the air, the calcium bicarbonate converts into limestone, which over time forms a stalactite.]]> 2017-11-03 18:39:18 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203439580 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203439669

Stalagmites form when water from the end of a stalactite creates a pile on a cave floor. Eventually, this pile becomes a stalagmite. As a result, stalactites and stalagmites are found in groups]]> 2017-11-03 18:39:29 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203439669 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203439847

Two glaciers erode parallel U-shaped valleys and form a narrow ridge of rocks called an Arête. 

]]> 2017-11-03 18:39:52 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203439847 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440113

Horns are formed when glaciers erode three or more arêtes, usually forming a sharp-edged peak.]]> 2017-11-03 18:40:33 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440113 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440156

Glaciers push downhill usually through a path already cut by streams. Glaciers seep into stream channels, and bit by bit, the glacier eats away at the curves of the original valley, carving a wider, straighter valley. Once the glaciers melt, a u-shaped valley is revealed.

]]> 2017-11-03 18:40:42 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440156 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440253

Cirques are concave, circular basins carved by the bottom of a glacier as it wears down the surrounding landscape.]]> 2017-11-03 18:40:57 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440253 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440322

Hanging valleys are formed when a main valley has been widened and deepened by glacial erosion. This cuts the side valley from the main valley below.]]> 2017-11-03 18:41:08 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440322 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440371

A moraine is material-usually soil and rock- left behind by a glacier in motion. This eventually builds up into a moraine.]]> 2017-11-03 18:41:17 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440371 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440424

When sediment rock expands, particles are lifted up at right angles to the slope. When the sediments shrink, due to heating/cooling, the particles fall back down. Creeps are created over a long span of time.]]> 2017-11-03 18:41:27 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440424 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440460

When gravity causes rock and/or soil to move down a slope a landslide occurs. Slow weathering of rocks as well as soil erosion, earthquakes and volcanic activity can all cause a landslide.]]> 2017-11-03 18:41:32 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440460 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440499

Flows are a mixture of water, rock and sediment that move quickly downhill. Flows can block roads or bury villages. When volcanoes  that are covered with snow and ice erupt, melted snow and ice mixes with mud and volcanic ash and flows down mountains. This is called a volcanic flow or a "lahar" ]]> 2017-11-03 18:41:38 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440499 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440572

The curved surface and rotation of material in a slump causes rock layers to be tilted backwards relative to rock layers beneath the slip surface. This can produce a dip that collects water and sediment. The material within a slump mass is not deformed, but rotated (distinguishes slides from flows).]]> 2017-11-03 18:41:48 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440572 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203440603

Rock fragments fall from the face of a cliff due to gravity. Freeze-thaw action loosens the rock. Water enters the joint, freezes and expands, cracking the rock. As a result, a slope of fallen rock is formed at the bottom of the cliff.]]> 2017-11-03 18:41:52 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203440603 2040073 https://padlet.com/2040073/vbi453aipdjb/wish/203442588

The sand in areas with pinnacles are composed of quartz and calcite. Rain dissolves and seeps calcite from the upper levels and precipitates calcite as cement in lower levels. At the base of the soil, a layer of calcrete forms isolating the lower portion of the dunes from the surface. It is then ruptured by plant roots, allowing the rain to dissolve calcite in specific areas, which become enriched in quartz sand. Later when the plants die and sand is blown away, these areas form the low spots between pinnacles.]]> 2017-11-03 18:46:42 UTC https://padlet.com/2040073/vbi453aipdjb/wish/203442588