DCPIP can be used to measure the rate of photosynthesis
DCPIP can be used to measure the rate of photosynthesis .
not measure the rate of photosynthesis as DCPIP blocked the ..
An interesting investigation that could make a good EEI is finding the relationship between density and weight%. This has been done for sucrose and the relationship is a cubic polynomial (see my graph below). The question is: does glucose have the same relationship? The method seems quite straight-forward: weigh out accurately 50 g glucose and add 50.0g water. Mix. This is a 50%w/w solution. Tare a 10 mL measuring cylinder and add the syrup up to the 10 mL mark. Note the mass and calculate the density. I'm sure you could work out a more accurate method. Try other mixtures: eg 20% up to 70%w/w. Plot (make sure you also measure the mass of 10 mL of water (ie 0% glucose) so you can plot that point too. For extra information see the article by Karen Peterson, Department of Chemistry, San Diego State University, California "Measuring the Density of a Sugar Solution" in Journal of Chemical Education, Vol. 85 No. 8 August 2008, pp1089-1090.
Pottery is one of the oldest human technologies and art-forms, and remains a major industry today. It is made by forming a clay body into objects of a required shape and heating them to high temperatures in a kiln to induce reactions that lead to permanent changes, including increasing their strength and hardening and setting their shape. Firing produces irreversible chemical changes in the body. As a rough guide, firing temperatures are in the range of about 1000 to 1400°C. However, the way that ceramics mature in the kiln is influenced not only by the peak temperature achieved, but also by the duration of the period of firing.
A good EEI (especially if you do Senior Art) might be to examine the hardness of the fired clay as a function of temperature; or as a function of time. If you were more adventurous you could look at different atmospheres within the kiln. One word of caution. This is a chemistry EEI and chemistry must be at its heart to distinguish it from applied technology or art. A pyrometric cone (see photo below) is a spike-shaped piece of clay used to measure temperature in a kiln when firing pottery. Cones have carefully calibrated melting points, indicated by their cone number. They are used to visually determine when a kiln has reached a desired temperature, by observing when a given cone in an observation port starts to droop. They are very attractive too.
Oxygen production is used to measure the rate of photosynthesis
But how to get samples of these gases? You may have cylinders but you could produce H2 and CO2 by reaction (or let some dry ice sublimate); let some liquid nitrogen evaporate (or remove oxygen from air). And why not propane (BBQ gas) or butane (cigarette lighter fluid)? Remember that balloon gas is not just helium - it has 3% air mixed in with it. The main point is that the law holds for ideal gases but at atmospheric pressure and room temperature they won't be that ideal. And is the deviation from ideality dependent on the molar mass of the gas, or whether it is polar or non-polar, and where on earth do you get a polar gas from (HCl is too dangerous)? What range of temperatures will you use (consider liquid nitrogen, dry ice). What value will they give you for absolute zero when the V/T graph is extrapolated? How do you draw the line of best fit (is least-squares the best, does it give you the most accurate value for absolute zero?). And what is the volume of the gas in the apparatus? And what is the best way to measure temperature (of the gas as in the diagram, or of the water surrounding it)?
Oxygen is evolved during photosynthesis but the conditions for maximum reaction rate are intriguing. It can be affected by many things, including: sunlight - its intensity and wavelength, temperature, CO2 and O2 availability, water (which closes stomata and restricts CO2), and any factor that influences the production of chlorophyll, enzymes, or the energy carriers ATP and NADPH, such as pH and Mg2+ availability. You could test the effect of pH and temperature. It sure won't be linear but how well your prediction (hypothesis) and results agree will be interesting. You could also try light intensity. If you don't have a "luxmeter" to measure intensity you could take advantage of the fact that as you double the distance of the light source to the plant, the intensity is quartered (but you'd have to cut out daylight). There are a lot of variables to control and complex biochemical reactions to examine.
Investigating the light dependent reaction in photosynthesis
As a trial, I took a 1 cm3 cube of marble and placed it in 200 mL of 7.5%w/v citric acid solution (pH 1.8) at 50°C (with stirring) and after 60 minutes it had lost 0.30 g. Why not make up a synthetic soft drink from phosphoric or citric acid. What concentration will you choose? How does the reaction rate or the extent of the reaction vary with concentration? Does temperature have much effect on the rate? Does the product - calcium citrate or calcium phosphate - impede the progress of the reaction; that is, how soluble are the products (one is 4 times as soluble as the other). How do you measure the progress of the reaction (amount of carbonate consumed or change in titratable acidity of the solution)? Oh, the possibilities are endless. And you can drink the left-over Coke and rot your teeth a bit more at the same time. A perfect EEI.
Anthocyanin pigments are responsible for the attractive red to purple to blue colors of many fruits and vegetables including dark wine grapes. Interest in the anthocyanin content of foods has also intensified because of their possible health benefits. They may play a role in reduction of coronary heart disease, increased visual acuity, as well as antioxidant and anticancer properties. Anthocyanins are relatively unstable and often undergo degradative reactions during processing and storage. Measurement of total anthocyanin pigment content along with indices for the degradation of these pigments are very useful in assessing the color quality of these foods. There is a method used for determining anthocyanins in wine. It was developed by Fuleki and Francis and you'll find it on the web. You'll also need a visible spectrophotometer (520 nm).
17/01/2018 · Measuring the rate of photosynthesis ..
Dichlorophenolindophenol - Wikipedia
DCPIP (2,6-dichlorophenol ..
that is normally the final electron carrier in photosynthesis
and thus is a good measure of photosynthesis
23/06/2009 · Can I use DCPIP to test for the rate of photosynthesis
Rate of decolourisation of DCPIP measures ..
Vitamin C is sensitive to heat and oxygen and the degree of sensitivity depends on the pH of the solution. In food it can be partly or completely destroyed by long storage or overcooking. By refrigeration the loss of Vitamin C in food can be substantially diminished. An interesting EEI would be to see how some of these factors really affect a Vitamin C solution. You could start with some fresh fruit juice (eg apple, orange) or you could simulate fruit juice by making up an appropriate solution with added citric acid, some citrates, glucose/fructose and so on. Should you measure the concentration of the ascorbic acid with time (eg daily) or just measure after a week or two weeks? What will you control? What will your independent variable be: sugar concentration, [H+], light, oxygen, temperature? If you intend to measure the concentration as a function of time elapsed you .
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