Senior Chemistry - Extended Experimental Investigations Please note: the suggestions below are just ideas for EEIs; they have been trialled but do not guarantee success. It is up to the teacher and student to see if they are practical for their school situation. Any task documents from schools are not exemplars; they are merely tasks that have been successfully used in assessment in Queensland schools but may have since been modified. Go to the How to do a Deadly EEI in Chemistry webpage. Go to the Biology EEI suggestions webpage. Want some experiments for a Physics EEI? Go to the Physics EEI suggestions webpage. Want some hints on Extended Response Tasks? Go to How to do a Deadly ERT in Chem webpage Scroll down for the EEIs. In Figure 2, a typical plant layout is provided to illustrate to the readers the processes involved. 1.3.1 Log sorting, conditioning and barking. Elm timber 4 elm tree butts for sale, Approximately 50 cube in each. Uckfield, East Sussex Advert Start Date: 31/1/17. RISK ASSESSMENT: Teachers in non- government schools may find the Queensland Department of Education and Training's Curriculum Activity Risk Management Guidelines (CARA) useful. Overseas exports are increasing, particularly to international markets seeking premium quality boutique wines. The Queensland wine industry has grown significantly over the years to cover a total of 1. The majority of this growth has occurred during the past 2. State. However, winemaking is still somewhat of an art but is strongly informed by science. Thus an interesting EEI can be undertaken in this context. THE MOST IMPORTANT INDEPENDENT VARIABLES IN FERMENTATIONThere are two key independent variables worth considering: (a) Sugar concentration. RESOURCES FOR STUDENTS & TEACHERS 'DEADLY' EEI IDEAS Ideas for Year 11 and 12 Chemistry Extended Experimental Investigations. From Dr Richard Walding, PhD, FAIP. FOR HIRE: TRACTOR WITH CRANE & WOOD TRAILER For woodland extraction of all wood types - pulp, timber, soft-wood etc. Erection of Log Barriers for land protection for. Appendix c : dallas road waterfront clover point and holland point history. The main arguments in favour of wind power are reduction in balance of trade deficits in countries that import energy and, longer term, mitigating for energy scarcity. After crushing the grapes the next step in the making of wine is the fermentation of the grape juice and pulp with various yeasts and bacteria. Most books say that the amount of ethanol produced is dependent on the sugar concentration of the starting juice but then give four different equations depending on assumptions made (such as the ratio and purity of glucose and fructose; or whether the fermentation gets 'stuck' at the primary stage). The most common relationship is a linear one (y = 0. EEI could investigate that. A good EEI would be to use fresh grape juice or simulate grape juice with 1. L glucose (or an equal mix of glucose and fructose), adding a controlled amount of yeast and wine acids and fermenting to stillness at constant temperature. Fermentation is an exothermic reaction so heat is generated during the process. To control the heat, the winemaker must choose a suitable vessel size or else use a cooling device. In the case of an EEI, you might control the temperature by use of a water bath (or a refrigerator). Typically, white wine is fermented between 1. Red wine is typically fermented at higher temperatures up to 2. Fermentation at higher temperatures may have adverse effect on the wine in stunning the yeast to inactivity and even . How temperature and the final concentration of alcohol are related would make an ideal EEI. OTHER INDEPENDENT VARIABLES WORTH CONSIDERING(c) Acidity. This is not such an important one and the effects may be small - but nevertheless important. You could repeat it with acidity as the independent variable and controlling the amount of sugar, yeast, temperature and so on. As the alcohol concentration rises the yeast cell membranes become susceptible to rupture by the ethanol. Some yeasts are more susceptible than others. Baker's yeast is very susceptible and will die at just a few % alcohol; brewer's yeasts (for beer) are okay up to 5% but some can survive in up to 9% alcohol; and wine yeast usually go from about 1. Sav Blanc), Riesling (1. Or you could look at the susceptibility of yeasts to . The interesting thing is that you could breed a yeast to survive higher alcohol concentrations (like they do at wineries for their malo- lactic fermentation of sparkling wines) by slowly increasing the amount of alcohol in the brew from say a few % to 1. This sounds more like a Biology EEI so I'd better stop here.(e) Sulfur dioxide. Sulfur dioxide is widely used in winemaking because of its antioxidant and antibacterial properties. You could hypothesise and test how SO2 affects the performance of yeast. SCHOOL WINEMAKING IN GENERALAny fruit (or juice) works just fine although some require more sugar to be added. The dragon fruit wine ended up being very expensive at approximately $1. Also, my winemaking unit for chemistry teachers is available online. It is worth stressing here that you should not taste the wine being produced; this is not because of the alcohol but rather because of the unsanitary conditions under which your wine is being made (in a lab, not the Home Economics kitchen). If you intend tasting your wine then your risk assessment should state and evaluate that. If I was your teacher I'd say . In this analysis, you add an excess of standardized acidified potassium dichromate solution to the wine which converts the ethanol to ethanoic (acetic) acid. The amount of unreacted dichromate is then determined by adding an excess of potassium iodide solution which is also oxidised by the potassium dichromate to form iodine. The iodine is then back- titrated with a standard solution of sodium thiosulfate and a starch indicator. The titration results are used to calculate the ethanol content of the original solution. It is complex but works well and is very impressive. You have a problem if you are dealing with red wine as the red pigments mask the colour changes. In that case you have to extract the ethanol from the wine (in effect, by various forms of distillation) and carry on, as above, from there. Canterbury University NZ has quite a simple method for red wine: see Canterbury - alcohol titration. Chemistry teacher Emma Hodginkson from Mountain Creek State High has performed the Canterbury ethanol titration with her Year 1. When analysing commercial wine, her students get very close to the %alcohol on the label. As it is a redox titration she says it works better in Year 1. Year 1. 1s find the calculations a bit heavy going. To overcome the practical difficulty in locating a small container to suspend above the dichromate - they use a plastic water bottle lid suspended with cotton thread. At All Hallows' School, Brisbane, chemistry teacher Matthew Stuart uses a more compact method: a boiling tube is used to hold the 2. L wine sample, and 8m. L dichromate solution is placed in a small . Some parafilm is used to seal the boiling tube, or a suitably sized stopper if possible. With care, the small inner test tube will float on top of the wine sample, and these are left in a drying oven (5. A pair of forceps is used to remove the dichromate tube without spilling into the wine sample, the outside rinsed with water, and then titrated. Manipulation of variables gives students a better chance of demonstrating all aspects of the assessment criteria. Yeast type and alcohol concentration in wine. You may have seen different types of yeast for different purposes; for example, there are beer yeasts (top- cropping ale strains and bottom- cropping lager strains); baker's yeast for bread- making; red and white wine yeasts; and even genetically engineered yeasts used for industrial alcohol production. Many are just different strains of the same yeast but grow differently. A good research question might be: how do different yeasts affect the production of alcohol from grape juice? Baker's Yeast - just $4. Woolies. The Lowans yeast to the right gives a faster rise I've found. You used to be able to buy 'compressed yeast' which is essentially a yeast suspension with most of the liquid removed. It is a soft solid, beige in color in foil- wrapped cubes. Winemaker's yeasts (Saccharomyces cerevisiae) come in different strains and are selected depending on the type of wine grape varietals being used. White wine yeasts are optimised for growth at 2. Red wine yeasts work best at 2. You can buy these from a 'Home Brew' shop or on- line for about $3 for 2. Today there are several hundred different strains of S. Some give a 'stinky fermentation' (as they say). Just your luck! There is a problem however. For example, temperature, p. H, sugar concentration, amount (mass) of yeast, surface area and so on. But when you are comparing two different categories of a variable, such as type of yeast (wine yeast vs. The choice of the categorical variables is not as common as using a continuous variable in Senior Chemistry EEIs, partly because categorical variables have their peculiar difficulties and this makes the design of this EEI far more complex than it looks at first glance. It is not just a matter of comparing equal amounts of the two yeast products on the amount of alcohol produced. A decision has to be made about the amount of each product to use to get some sort of equivalent mass of yeast for comparison (and how this is arrived at; is there any indication of the % composition of the two products). Do the yeasts each have an optimum p. H and if so what p. H will be chosen for the grape juice (and why)? I know that the Lalvin BGY yeast from Burgundy, France is hopeless at p. Hs lower than 3. 2 but other work at higher p. Hs. Is surface area a concern (maybe if one is a bottom fermenter, and another a top fermenting yeast). What temperature will be used (and why) if the yeasts have their own optimum temperature for growth; for example the BGY Lalvin yeast from Burgundy, France works best at 2. Will a low sugar or high sugar juice be used - important as it may be the alcohol itself that inhibits the yeast. For example, the Lalvin CLOS yeast from Spain is high- alcohol- tolerant up to 1. And what about the dependent variable (alcohol concentration): will the rate of alcohol production be measured, or just the amount of alcohol present when the yeasts die or the sugar runs out; or will the alcohol be measured after a set time, eg 7 days? Some yeasts are slow (eg the CY3. Slow White yeast from France takes its time but gets there in the end; it would be a brave decision to cut it off after 7 days). Lastly, some yeasts convert malic acid to alcohol (as well as converting the sugar). Viking Ships of Roskilde Back to Archaeological Sites. Five Viking Ships. Towards the close of the Viking Age - presumably at some time between 1. AD - the fairways of Roskilde Fjord were blocked by a series of barriers to protect the important trading town of Roskilde from attack by enemy fleets. The five viking ships in the museum come from one of these blockages in the Peberrende channel at Skuldelev, 2. Roskilde. Here, three ships were sunk across the channel and boulders heaped up on top of them. A little later the barrier was strengthened by a further two ships at the spot. It was at a time when Norwegian Vikings were ravaging Denmark, but we have been unable to link any definite historical event with the blockage. The blockage manifested itself as a ridge of stones. It had always been known to fishermen in the fjord and local tradition claimed that it contained a ship sunk at the command of Queen Margrethe I, . In a period of less than four months all five ships were excavated and brought to land in thousands of fragments. Note the long pier leading from the cofferdam, in shallow water, to a landing stage in deeper water, to enable easier access to the site by boat carrying heavy or bulky items when necessary. It appears that a pedestrian walkway gave access to the site from the land to the SSW. Slowly the water level lowered, and eventually five Viking ships came into view at one of the most significant archaeological sites in Denmark. Photo: http: //www. VGkub. Fdrs. 8g. After the cofferdam was pumped out, the salvage work could begin in earnest. The exposed timbers, however, had to be prevented from drying out by mists of water from sprinklers attached to hoses, or they would have powdered into dust. Diesel pumps were no doubt used to maintain the water pressure night and day. They worked under severe difficulties. For many years, Danish fishermen had reported a sunken ship blocking a narrow channel in the fjord leading southward from the Kattegat sea to Roskilde. Salvaged fragments showed that the wreck was from the Viking period. Lured by these fragments, staff members at the National Museum, headed by Olaf Olsen, took lessons in frogmanship, and in the summer of 1. Note that ships 2 and 4 are now treated as one, ship 2. The designation 'ship 4' has been abandoned. Moreover, the divers found not just one, but possibly six small ships filled with rocks. Some of the vessels lay on top of each other, some in a row. The amateur frogmen from the National Museum found the fjord wreckage extended one hundred and fifty feet in length, and thirty to fifty feet in breadth, in some places only three to ten feet below the surface. The individual ships averaged forty to sixty feet in length, perhaps ten feet wide and four feet in width. The numbers indicate the depth in metres before the sinking of the ships and the arrows mark the three navigable stream furrows. Excavation under water is a painstaking operation. At times, they could work in waist- deep water, using skindivers' goggles but not needing diving apparatus. More often they wore rubberised, watertight suits and laboured below the surface equipped with a full mask and two air cylinders. They cleared away seaweed, shells and mud, aided by a helper on a pontoon anchored near the wrecks. The helper watched their lifelines and airtubes, and kept their fire hose working properly. The fire hose was their most important tool. The usual aids to archaeology- shovel, trowel, and brush- proved useless, merely stirring up the mud and blinding the diggers. With the fire hose they could remove debris from the site without complete loss of visibility. The hose poured a gentle stream under water, so that the ships weren't further disintegrated by the digging. Also, the divers could manipulate a full- pressure backwash from the hose to propel themselves horizontally through the water. Mud would be churned, and they would have to work blind for a few minutes, then wait motionless until the water cleared. Floating seaweed altered the appearance of the bed almost daily. Olsen said, 'it lacks the clarity of the Mediterranean.'So to keep their bearings, they stretched a steel wire marked at metre intervals along the blockage, and used this as a guide with fixed points on land to draw a map of the project site. For this task they sketched with a soft pencil on special waterproof paper stretched in a plastic frame which was strapped to the diver's forearm. The map then served as a blueprint as they continued to toil in the murky depths. To prevent portions of the wrecks from floating away with the current, only small parts were exposed at a time. The museum was originally constructed in 1. Skuldelev ships. It was decided in the 1. Viking ship replicas. This ship, too big once conservation was complete to be housed at the museum itself, has now been on public display in Copenhagen, London, and Berlin during 2. Andersen. Photo and text: Hocker et al. Photo: Don Hitchcock 2. Source and text: Roskilde Viking Museum, Denmark. Skuldelev 1 - The ocean- going trader. Photo: Don Hitchcock 2. Source: Roskilde Viking Museum, Denmark. Skuldelev 1 - The ocean- going trader. Photo: Don Hitchcock 2. Source: Roskilde Viking Museum, Denmark. Skuldelev 1 - The ocean- going trader. Photo: Don Hitchcock 2. Source: Roskilde Viking Museum, Denmark. Skuldelev 1. Design Element. Details. Materialpine, oak, and lime. Length. 15. 8. 4 metres. Breadth. 4. 8 metres. Draught. 1 metre. Displacement. 21 tons. No. Ottar was built of oak, pine and lime at the museum boatyard in 1. Like Skuldelev 6, the original Skuldelev 1 was built in Sognefjord in Norway around the year 1. Common to both ships is the special longitudinal change in angle along the bottom of the boat under the waterline, the chine, resulting from the almost vertical planking midway in the otherwise curved cross- section. Presumably the purpose was to provide more resistance to leeway in a vessel with shallow draught and at the same time reduce friction and turbulence by creating two parallel spirals in the water flow under the bottom to increase the speed and make steering easier. Amidships there are two capacious holds and, for and aft, large manoeuvre decks. It must be the type of ocean- going ship the Vikings called a 'knarr' and which, according to written sources, was the only type of ship that sailed to Greenland. This small 'knarr' is hardly likely to have made such a voyage even though the 'Saga Siglar', a Norwegian reconstruction, visited Greenland on a round- the- world voyage in 1. The original ship was most probably an 'austfarerknarr. The manufacture of the 9. Ottar was a project in itself during which assistance was received from textile researchers in Denmark, Norway, Sweden, England and Scotland. A great deal of the practical work in recreating the sail was carried out at the special exhibition organised by the Viking Ship Museum, 'Sails', in 1. The wool came from as many as 2. Spelsauer' sheep - descendants of Norwegian wild sheep. Each one of these rather small sheep yielded about 5. This had to be spun very tautly and woven incredibly densely to achieve a woollen material which was suitably windproof and durable. To make sure the sail repelled water and that it was even more wind- proof, the finished- woven sail was treated with raw ochre and a mixture of horse mane fat and water in the ratio of 1: 1. The mixture was boiled, cooled down and then rubbed into the sail using glass stones. It is interesting to note that it was the ochre that made the sail tight - and yellow - not the fat. After the sail had been in use for a certain time beef suet was kneaded into the front side to make the surface smooth. The rigging rope work is also made of authentic materials. The standing rigging that braces the mast is of hemp while the running rigging for the sail is made from horse hair. As an experiment, a little linden bast rope has been used for the centre sheets ('prierne') and for the ribands that fasten the sail to the yard using reef knots ('r. The cargo- carrying capacity is 3. It is a longship, possibly of the skeid type. It is approximately 3. Photo: Don Hitchcock 2. Source: Roskilde Viking Museum, Denmark. Text: Wikipedia. Skuldelev 2. Dendrochronology showed that the ship was built in the Dublin area around 1. The shape of the ship would have allowed for great speed, up to 1. It is one of the longest Viking- ships ever found. Photo: Don Hitchcock 2. Source: Roskilde Viking Museum, Denmark. Text: Wikipedia. Skuldelev 2 A ship was deemed seaworthy if it only needed bailing three times in two days. Sheep wool and tar was used for caulking between the planks. The original ship was built around 1. Dublin with oak from Glendalough, Wicklow, Ireland, hence the ship's name. The reconstruction was built at the shipyard of the Viking Ship Museum in Roskilde from 2. Havhingsten fra Glendalough is a reconstruction of the second longest Viking longship that has been found so far, the longest being Roskilde 6, found during the excavations for the extension of the Roskilde Museum. To this can be added (for the original) the 1. The original ship had impressive rigging. The 1. 3 m long keelson and the many keelson knees illustrate the ship’s advanced technical level and daring construction. Everything is minimised in dimension and weight without weakening the strength of the construction. Calculations of the ship's hull- rigging- rudder balance formed the basis for the construction of the 1. Photo: Don Hitchcock 2. Text and source: Roskilde Viking Museum, Denmark. Additional text: Wikipedia and http: //thevikingships. This is Skuldelev 3, a 1. Byrding type. It is made from oak, and was constructed somewhere in Denmark. It would have been well- suited to shorter journeys in Danish waters and the Baltic Sea. Photo: Don Hitchcock 2. Text and source: Roskilde Viking Museum, Denmark. Additional text: Wikipedia and http: //thevikingships. A good shot from a high angle of the interior of Skuldelev 3. Photo: Don Hitchcock 2. Descriptions of manufacturing processes. Introduction. 1. 2 Sawmilling. Plywood production. Particleboard production. Due to the adoption of energy conservation measures it was necessary to make a- detailed analysis of the process involved and equipment used in such a process. This analysis had to identify the amount, type and quality of energy required so as to identify possible energy savings compatible to the respective cost- benefit analysis. It implies a certain number of operations from handling and transportation of logs to timber drying, sorting and classification which require different types of energy. Whereas in developing countries most of the processes are highly mechanized and the energy requirements are met basically with the generation of a few k. W to drive the main saws. The rest of the processes are carried out using animal power and low- cost manpower. Sufficient quantities are stockpiled to ensure the sawmill's continuous operation, particularly during adverse weather conditions when log extraction and supply from the forests may be adversely affected. Manual and animal power, as may be used in small portable sawmill units, through to log- carrying front- end loaders and overhead cranes indicate the wide variety of handling equipment currently in use. Sawmilling - A simplied process flow. Debarking of logs, whether it be undertaken manually or by mechanical debarkers, in the forests or at the mill site, is now becoming a generally adopted practice. Debarking is to safeguard saws and other equipment from undue wear and damage that would otherwise result from stones, metal and other such contraries embedded in the bark; debarking also facilitates the head sawyer to evaluate the timber. Log washers may also be used to remove any remaining sand or dirt that may adher to the logs' surface. Before the log is presented to the headrig for breakdown, it is cut to the longest permissible straight length with a cut- off saw, whereupon it is loaded onto the headsaw carriage and positioned in such a manner as to allow the operator to achieve a sawing pattern, which will result in the optimum production of sawntimber with the minimum of waste. The pattern of cut is largely determined by the dimension and condition of the log, as well as the market requirements for the widths and thicknesses of the lumber. A log carriage conveys the log through the headsaw on which the log may be clamped and turned, so as to enable it to be presented to the headsaw in order to achieve the best sawing pattern. The rough round edges of the pieces coming from the headrig and resaws are removed by either a circular saw or chipper edger so as to produce standardized widths as required. Grading is a means to segregate the lumber according to the overall quality, direction of grain, presence of knots and defects, as well as general appearance, etc. Wax or paint is applied to the end- grain of lumber to be air- dried, either by brush or spraying, so as to act as a sealant in order to bring about a slower drying of the extremities and hence, give rise to a more uniform drying of the lumber. Sawntimber that is not sold green is either air- or kiln- dried, thus improving its marketability. By drying and lowering the moisture content to an acceptable level its value is enhanced by virtue of the fact that the timber is dimensionally stabilized and its strength and colour improved; also a reduction in weight lowers transport costs. The two most common kilns are the batch and progressive type. The former dries the timber in chambers as a batch charge, whereas the latter dries the timber whilst it progresses through the length of the kiln on trucks. Handling may be by heavy lift trucks, derricks or cranes, all of which are sized to cater for the logs' dimensions and weight. Plywood production - A simplified process flow. Before peeling, the majority of timbers need to be conditioned so as to soften the wood in order to facilitate peeling and to produce an acceptable quality of veneer. Conditioning involves the exposure of the peeler blocks to both heat and moisture by way of soaking in hot water vats or exposed to live steam or hot water sprays. Any defects, such as knots and splits, are then cut out of the sheet. The drying of veneer, to between two and ten percent moisture content, is to aid the gluing process during the manufacture of the plywood. Depending on the location and sophistication of the plywood mill, the veneer sheets may either be left outside to dry in the air or kiln- dried. Kiln- drying involves the drying of stacked veneer in batches or the continuous drying of sheets which are mechanically conveyed either on a continous belt or roller system through the length of the dryer. Obviously a controlled drying environment, with minimal handling, will result in a more uniformly dried veneer, with the least amount of damage. For this reason new and improved drying systems are being constantly developed, as well as the manner in which they are heated. Although drying temperatures of between 9. Glue is then applied to the inner plies or core, which in turn, are laid between the outer veneers ready for bonding. This operation accounts for a large share of the manual labour employed in the production process. Heating of the platens is generally by hot water or steam, although thermic oil is used when pressing at higher temperatures. This is largely due to the fact that veneer stuck together is easier to handle and load into the hot- press, added to which the ply's reduced thickness allows for smaller daylight openings in the hot press resulting in an overall reduction in loading and hot pressing time. Primary finishing, which entails the trimming, sanding and upgrading of the plywood after pressing, is undertaken so as to enhance the marketability of the product. It is carried out at either separate work stations, or, in the case of modern mills, as a combined operation in a continuous semi- automatic line. Damage or imperfections to the face veneers are then manually repaired by plugging and the application of patches. Thicknesses may range from 3- 2. Particleboard production - A simplified process flow. Particleboard furnish is derived from a multiple of sources and as the competition for solid wood and solid wood residues increases, manufacturers are having to resort to the use of low grade residues, such as hogged mill waste, sawdust, planer shavings, etc., as well as wood species not previously considered. Bark is removed from logs, if not already done in the forests, so as to avoid blunting chipper knives, and the provision of stone- traps and magnetic separators safeguard other reduction equipment from damage which would otherwise be caused if contraries were introduced with the fibre furnish. Chippers, knife- ring- flakers, hammer mills, disc refiners, etc., each operating on a different principle, using either knives, hammer bars, grooved disc plates, etc., are but some in common use in the industry. The greater part of the furnish delivered to the mill needs to be dried so that the overall moisture level of the particles is in the order of three to eight percent for the purpose of bonding with liquid resins. Heat is produced by the combustion of oil, gas or process residues. Flash drying is now being considered an acceptable alternative to rotary dryers and requires somewhat lower drying temperatures. Screening normally takes place after the dryers as moist particles tend to stick together, plugging screen plates and lowering the overall efficiency of the screening process. It is essential that the oversized particles be recycled for further reduction and that the fines are screened out, so as to avoid consuming a disproportionate amount of resin binder, and to provide a valued source of fuel. Adhesives in the form of urea, phenol and melamine formaldehyde are generally used to bind together the particle mix, with the former being the most favoured resin in use. Between three and ten percent by weight of resin, together with other additives used to impart such properties as fire resistance, etc., are blended under controlled conditions in batches or as a continous operation. Blending may either take place in large vats at slow speed, or in small blenders with rapid mixing and shorter blending times. In spite of the wide variety of formers currently available, the underlying principles of mat formation are generally similar, in that a uniform flow of particles are fed to the former from a surge bin, which in turn meters an evenly distributed layer of particles into a frame on a moving belt or caul. In all cases it is paramount that an evenly distributed mat of the desired weight be formed. Mats that do not conform to standard are rejected and recycled. This allows for ease of handling and the use of narrower openings in the hot- press, thereby considerably reducing pressing time. Although in the larger modern installations both pressing time and pressures are automatically regulated, hand control is still preferred in many plants as it permits adjustments to be made for the different mat qualities. On leaving the hot press the boards are either separated from the cauls by hand, or mechanically by means of chains or turning devices. The cauls are stacked, allowed to cool and then returned to the forming station on push carts or mechanically transported on a fixed return line. The boards in turn, are cooled and conditioned so as to avoid degradation of the urea resins. In order to meet set standards as to thickness and surface quality, a combination of knife planers and belt or drum sanders may be used. Particleboard is normally produced as 1. Generally boards are manufactured in the medium- density range of 4.
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