(a) Sugar concentration. 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 = 0.6x -1) - so an EEI could investigate that.
This process is called photosynthesis. Temperature, carbon dioxide concentration and light intensity are factors that can limit the rate of photosynthesis.
The toxicity of copper to algae has been the subject of a number of studies over the past 40 years because of its widespread use for the control of algae in natural waters. This suggests a good EEI. You could try growing algae in solutions with different copper ion concentrations from say 0 to 1 ppm. One problem you will have to sort out is how to measure the amount of algae in the samples. Perhaps it can be done using a spectrometer, or by measuring the depth at which you can just see a black cross appear/disappear (like in a simple tube they use in Biology, or like the Secchi Disk method for turbidity in natural waters). Safety note: copper is a heavy metal ion and is considered hazardous. It is important that you become aware of the risks. Care should be used when handling this product.
The last thing you want in your swimming pool is algae - the green plant that grows on the walls and bottom of the pool. There are several ways to control it: keeping the sanitizer (chlorine) levels correct helps but often a copper-based algicide (algae killer) is used. The copper ion (Cu2+) is a very effective algicide to both kill and prevent algae formation. Swimming pool companies say that about 0.03 to 1.0 mg/L (0.03 to 1.0ppm) of free copper ion must be present to be effective and safe. The word "free" is used because "bound" copper (copper is tied up in an insoluble form) is not available to work as an as algicide. For non-biological systems (where no living plant or animal is present) a continuous level of 1.0 ppm is enough to assure effective algae control; more is superfluous and may damage surfaces and equipment.
An interesting study by Drs Jenny Stauber and Mark Florence from CSIRO's, Division of Energy Chemistry, Lucas Heights Research Laboratories, Sydney, Australia found that copper ions depressed both cell division and photosynthesis in many species of algae notably the common freshwater green alga, "Chlorella" (). Reference: J. Stauber and T. Florence, 'Mechanism of toxicity of ionic copper and copper complexes to algae', 94, 511-519 (1987).
In their experiment they maintained in MBL medium on a 12 hour light: 12 hour dark cycle (Philips 40 W fluorescent tube, white, 6500 K - see photo below) at 21°C. They found that a Cu2+ concentration of 7.9 x 10-7M (5 x 10-5 g/L, equal to 0.05 mg/L or 0.05 ppm) gave a 50% reduction in growth. to see what the MBL medium consists of (this may be too complicated for high school EEI). One question you need to sort out is how to measure algae growth (perhaps measure the absorbance in a spectrometer).
To kill algae in a swimming pool either ionic copper (in the form of copper sulfate) or chelated copper can be used (see above). Pool manuals and pool chemical suppliers say that the problem with using the ionic form - copper sulfate pentahydrate, CuSO4•5H2O - as the algicide is that it doesn't last long in pool water. Pool water has carbonate ions (CO32-) present from the addition of sodium carbonate or sodium bicarbonate as a buffer against pH changes. The carbonate ions react with the added copper sulfate to form a precipitate of copper carbonate: Cu2+(aq) + CO32-(aq) → CuCO3(s). So it would appear that any copper ions added to pool water would immediately be precipitated as the carbonate and thus not available to kill algae.
Paper chromatography is an analytical chemistry technique for separating and identifying mixtures that are or can be coloured, especially pigments. This can also be used in secondary or primary colours in ink experiments. Most leaves are green due to chlorophyll. This substance is important in photosynthesis (the process by which plants make their food). You have probably done experiments where the different pigments present in a leaf are separated using paper chromatography. However, to make this a good EEI you need to take it further. Which is the optimum solvent (propanone, ethanol, hexane etc) and why (polar, non-polar, low viscosity, high BPt and so on)?