Deposition science refers to the study of how sediments (soil, rock particles and pebbles) accumulate on Earth’s surface through weathering and erosion processes.
As an engaging hands-on activity that will enable your students to visualize deposition, create a landscape in your backyard and set up two large containers.
Sediment transport refers to the movement of solid particles through water. Sand and dirt particles are transported via erosion by water, wind, glaciers or the sea before losing kinetic energy and falling back to earth – hills or buildings can speed up or slow down this process, altering sediment transport’s timing accordingly.
Erosion and sediment transport are vital parts of our natural environment, yet they can be problematic as well. For instance, erosion can carry harmful chemicals from farms into rivers and streams which pollute drinking water, making it unfit for consumption and leading to health concerns for residents downstream.
Sediments may come from either organic or mineral sources. Mineral-based sediment is known as bed load while organic sediment is known as suspended load. As bed load moves along a sedimentary bed and is lifted up by traction, its particles become rolling grains; those not lifted up as high by traction remain low suspension while any that ride higher up in the flow flow are known as saltation.
Weathering, which involves both physical and chemical decomposition of rocks and minerals exposed to our atmosphere, involves breaking them up into smaller bits that can then be carried by erosion; both processes work in concert to change Earth’s rocky landscape continuously.
Weathered rock particles can be transported by erosion to new locations where they will eventually settle as sediments. Weathering acts to smooth rough, sharp rock surfaces and is the first step in soil formation, mixing small bits of weathered rock with plant, animal and fungal remains to create fertile soils that nourish plant, animal and fungal life.
Weathering is also responsible for creating Aeolian sand dunes and dispersing plumes of air pollution, volcanic ash or wildfire smoke; and can convert carbon dioxide gas to solid dry ice. Deposition is the opposite of sublimation which involves changing solid matter directly to liquid form; kids typically explore states of matter and changes of state beginning around year 4 (aged 8+). Deposition process provides an example of such change of state.
Erosion is a natural process that loosens, removes and transports weathered or unweathered solid material like soil, mud, regolith and rock fragments, shaping hills and valleys while also creating coastlines and lakes. While erosion may be destructive at times, it also provides raw materials needed for new geological formations like beaches and coal seams.
Wind, water waves and ice provide the necessary mediums to transport particles; when an erosion agent such as glaciers, rivers or wind lose energy they stop carrying the eroded material resulting in deposition where sediments drop from their transport medium and accumulate on surfaces.
Your students may find deposition easier to grasp if they are studying states of matter such as gases and solids in Year 4 onwards (aged 8+). Frost can help them visualize how gas changes directly to solid without going through liquid phase first.
Depositions are an essential component of the discovery process in legal cases. They allow attorneys to learn what witnesses may say during trial and form strategies on how best to argue either for or against them, which could dramatically change the outcome. It’s crucial that an experienced lawyer accompany you during depositions; they’ll assist with preparation for opposing counsel’s questions as well as help keep any comments that might damage your case to a minimum.
Deposition transcripts will also ensure an accurate representation of what was said at your deposition, which can help ensure any discrepancies during trial. Court reporters sometimes make errors; should this occur during your deposition, ask for clarification immediately and sign the transcript once corrected to avoid confusion at trial. Using similar techniques as dry ice production by manipulating temperature and pressure of carbon dioxide gas molecules; frost often forms on cold surfaces like windows or metal.