Geologists use deposition as a way of understanding past environments.
Beginning in year 4, teachers introduce children to different states of matter and how their states change over time, including deposition processes.
Deposition occurs when substances move directly from gas phase to solid phase without going through liquid phase, such as frost.
Erosion
Erosion is the natural process by which bits of rock and soil wear away from one location on Earth’s surface and are carried to another location through weathering; this differs from weathering, which involves breaking down rocks without moving them around. Eroded material is known as clastic sediment.
Water erosion is the most prominent form of physical erosion, caused by rivers, waves and floods washing away bits of dirt from their path. Plant roots and vines can also contribute to physical erosion through bioerosion; breaking up rocks as they grow.
Erosion can be devastating, triggering landslides and mass wasting events that devastate entire communities in their path. But erosion can also be beneficial, creating fertile river deltas and depositing sediment into deep valleys. Wind erosion sculpts rocks into dunes such as those seen in Badain Jaran section of Gobi Desert while Arches National Park of Utah boasts numerous sandstone arches created through wind erosion.
Changes in Agents of Transport
Once erosion dismantles rocks or other materials, their particles are picked up by various natural agents like wind, water, gravity or ice and transported to new places. When an agent carrying this sediment runs out of energy or reaches gently sloping terrain it stops transporting and deposits its collected sand and gravel on land as part of what’s known as sediment deposition.
Material that accumulates as deposits includes pebbles, sand or salts which result from dissolving minerals in water; dunes or beaches also deposit their own share.
Students aged 8+ should be introduced to the concept of matter and changing states from year 4 onwards (age 8+). Students can observe its transformation by watching frost form on cold surfaces or ice crystals form in cirrus clouds; then relate these observations with chemical coatings deposition, such as bug bombs or industrial materials used for purification purposes.
Changes in Temperature
Once erosion starts, it can continue until its agent of transport (gravity, ice, water, wind or waves) runs out of energy to carry away eroded particles; at which time sediments begin to build up on land surfaces and are eventually deposited as deposits.
Size and terrain will have an effect on how far a particle travels before being deposited; larger particles and boulders typically only travel short distances before becoming stationary, while smaller particles and sandy soil could travel much further before finally coming to rest.
Frost is a good example of deposition. When warm air encounters a surface that has low enough temperatures, such as leaves or metal windows, water vapor in the air changes directly into ice without passing through liquid phase, creating frost directly without passing through liquid phase; this process is known as deposition or sublimation and only happens at freezing temperatures; additionally it can also be used to create dry ice as seen by Multimedia Choice “Ice on a Can”. For more details about how it all works click on this Multimedia Choice “Ice on Can” Multimedia Choice “Ice on Can” Multimedia Choice will provide more information regarding this topic.
Changes in Pressure
Sediment is transported through natural forces such as water, wind, gravity and glaciers. They transport it from one location to another before depositing it on another surface – depending on factors like particle size, shape, speed of transport and terrain coverage (for instance sand grains carried by winds may form dunes).
Energy of natural agents also plays a part in deposition. For instance, slower agents cover less distance. Particle size also has an impact; heavier particles move further.
Deposition, the opposite of sublimation, refers to the process by which gaseous elements change directly to solid forms without passing through liquid states first. An example would be frost forming on cold surfaces or clouds containing frozen raindrops forming as ice crystals.