6: Option - Shipwrecks, Corrosion and Conservation
6.1: The chemical composition of the ocean implies its potential role as an electrolyte
Identify the origins of the minerals in oceans as:
leaching by rainwater from terrestrial environments
hydrothermal vents in mid-ocean ridges
Identify - recognise and name
There are 2 major sources of the salts in seawater:
Leaching by rain and ground water.
Dissolution of salts by water passing through hydrothermal vents.
LEACHING BY RAIN AND GROUND WATER
The main ions that are dissolved as rainwater percolates through the soil and makes its way into creeks and rivers are Na, Ca, Mg, Cl and SO4.
Water that seeps down into underground aquifers dissolves greater quantities of these ions and under certain conditions (slightly lower pH than normal) picks up significant amounts of Hydrogen Carbonate (by dissolving carbonate)
Small amounts of nitrate and phosphate are also dissolved: these result from decay of plant and animal matter.
Although leaching of salts from the ground is a natural process, it has been significantly increased by human activities such as clear felling of forests, land clearing for pastoral pursuits and cultivation for crop growing.
Some underground aquifers pick up high concentrations of sodium chloride (from the many salt deposits that exist there), and these carry large amounts of salt to the oceans.
HYDROTHERMAL VENTS
Mid-ocean ridges (often containing fissures or cracks in the rock) exist near the Earth's crust.
Seawater is able to percolate down these fissures and come close to ...
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Different metals and their corrosion rate
Metal Observation at start Observation of metal after 3 days
Aluminium Silver and shiny No change
Tin Silver and shiny No change
Zinc Silver and shiny No change
Iron Silver and shiny A coating of rust formed on the nail
Brass Gold and shiny A coating of corrosion formed on the topside of the tack and some corrosion was seen in the water.
Stainless Steel Silver and shiny No change
Plan and perform a first-hand investigation to compare the effectiveness of different protections used to coat a metal such as iron and prevent corrosion
Compare - show how things are similar or different
Gather and process information to identify applications of cathodic protection, and use available evidence to identify the reasons for their use and the chemistry involved
Identify - recognise and name
Combined with corrosion fatigue” (“Silver”).
This is evidence for continuous formation of new rock at the ridges. As more rock forms, older rock is pushed farther away from the ridge, producing symmetrical stripes to either side of the ridge. In the diagram to the right, the dark stripes represent ocean floor generated during "reversed" polar orientation and the lighter stripes represent the polar orientation we have today. Notice that the patterns on either side of the line representing the mid-oceanic ridge are mirror images of one another.
and Metamorphic rocks can be found. There are also a lot of crusted plates, and violent
The Mid- Atlantic Oceanic Ridge is the best known divergent boundaries. Divergent boundaries are when two plates move apart from one another. The Mid-Atlantic Oceanic Ridge is spreading at an average of 2.5 centimeters a year ("Understanding plate motions [This Dynamic Earth, USGS]", 2014). This underwater mountain range a prime example of seafloor spreading as well. Seafloor spreading creates new oceanic lithosphere when the two plates pull apart and magma is allowed to well up and fill the crack. This also causes underwater mountains to form if the magma flows upwards past the crust (Tarbuck & Lutgens, 2015). It is important to understand how these ranges are created, especially because they can give scientists an idea on when new islands or continents may be formed. It also allows scientists to understand what may cause other plates to diverge from one
Through industrial and consumer waste, heavy metals can enter a water supply or even from acidic rain breaking down soils and discharging heavy metals into streams, lakes, waterways, and groundwater. Some overwhelming metals incorporate:
Convection currents deep in the mantle of the earth, begin to well up towards the surface. As the pressure increases, it sets the crustal plates in motion. There are different kinds of mountains - Volcanic, Folded, Fault-block, and Dome mountains. Volcanic mountains are formed when magma comes up through cracks in the Earth’s crust and explodes out of lava and ash. The Hawaiian volcanoes, Mt. Hood, Mt. Etna, Vesuvius, and Mt. Saint Helens is an example of volcanic mountains.
However, when the pH levels reach a certain stage, the iron can then precipitate out, coating sediments with the characteristic yellow, red or orange colourings (D.E.P. 2, 2002; U.S.G.S. ; U.S.E.P.A., 2002). The rate that A.M.D. advances is also influenced by the presence of certain bacteria (Doyle; U.S.G.S). A.M.D. that has dissolved heavy metals such as copper, lead and mercury can contaminate ground and surface water.
Corrosion is by far the greatest concern when it comes to aging aircraft. Corrosion is a deformity that occurs at the surface and subsurface of the structure and components of aircraft. This creates a greater need for advance techniques and inspections used to detect these deformities. Some techniques talked about in this paper that are used to detect corrosion are non-destructive testing, and different scheduled inspections.
Corrosion can take place on many different materials ranging from metal, being one of the more common materials to corrode, to some ceramics and polymers. Corrosion is typically an electrochemical reaction that takes place with the material being degraded as it reacts with its surrounding environment. When this reaction takes place, the metal gives up electrons which aids in the rust and oxidation formed on the metal. Corrosion usually takes place because most materials are manmade and therefore are unstable and tend to try and revert back to its original state. As an example you can picture a plate of uncoated steel hanging outside. Over a period of time the steel plate will begin to corrode do to its reaction with the oxygen in its surroundings. If you take that same steel plate and add water in the mix, it will corrode at a more aggressive rate then the plane steel because the water allows for more oxygen and iron ion reactions. Now take that same plate and put it in a salt water environment and it will corrode at an even more aggressive rate due to the presence of sodium chloride ions.
Ocean water is often referred to as salt water. Ocean water becomes salty as water flows in rivers, it picks up small amount of mineral salts form rocks and soil of the riverbeds. This very-slightly salty water flows into the oceans. The water in the oceans only leaves by evaporating, but the salt remains dissolved in the ocean, it does not evaporate. So the remaining water gets saltier and saltier as time goes on.
A mountain is the most basic result of two plates colliding. A mountain is formed when two continental plates collide, the plates crunch and fold the rock at the boundary, lifting it up and forming mountains and mountain ranges. According to the science textbook on page 206 lines 19-22 the text states “Two plates carrying continental crust can also collide. Then, neither piece of crust is dense enough to sink far into the mantle. Instead, the collision squeezes the crust into high mountain ranges.” The second possible landform that is caused by a convergent boundary is a deep ocean trench. A deep ocean trench is an underwater subduction zone involving two oceanic plates, or a continental and oceanic plate. A subduction zone is where two plates collide and the older, denser, and colder tectonic plate goes under (or subducts to) the newer, less dense, warmer tectonic plate. The plate which had more time to cool subducts under the hotter plate because in a colder substance the molecules are closer together which makes the plates substance more dense which causes the plate to sink. Whereas in a warmer substance, the molecules that make up the object are farther apart and are
The most prevalent source of agricultural water pollution is soil that is washed off of fields. These fields have been treated with fertilizers and pesticides, which over time have accumulated heavy metals that are then transferred to lakes and streams. The excess particles cloud the water blocking vital oxygen and sun for the aquatic plants.
In our days, mining for resources is inevitable. The resources we need are valuable in everyday life. Such resources mined up are coal, copper, gold, silver, and sand. However, mining poses environmental risks that can degrade the quality of soil and water, which can end up effecting us humans if not taken care of and many of the damages are irreversible once they have occurred.
Is it just a big mistake? Is it really the salt 'fault'? Are there any solutions to fixing this problem? These are some of the questions many people should be asking before deciding if salt is a friend or foe. Instead of just following whatever others say, people should know exactly how soil salinity is affecting crops and why this is happening.
The concurrent convective circulations in the mantle leads to some segments of the mantle moving on top of the outer core which is very hot and molten in nature. This kind of movement in different segments occurs as tectonic plates. These tectonic plates are basically seven on the earth surface as major ones, although, several small ones exist also. The plates motions are characterized by varying velocities, this variance results to sub sequential collision of two plates (leading to formation of a mountain in a convergent boundary), drift of two plates (leading to formation of rifts in a divergent boundary), or parallel movement in a transform boundary(Webcache 3).