E-learning: Determination of substrates pH // Subtratų pH nustatymas Dubravos apyrubėje

E-learning: Determination of substrates pH // Subtratų pH nustatymas Dubravos apyrubėje


Determination of substrates pH in Dubrava Minor Rerserve. Teacher Ingrida Raguckienė. Kaunas Juozas Grušas Art Gymnasium Hello, I am Ingrida Raguckienė – Chemistry and Technologies teacher in Kaunas Juozas Grušas Art Gymnasium. Participating in the project – learning in the nature and learning from the nature. With first Gymnasium class students we will have lesson in the nature – determination of substrates pH. The lesson will be taken in Regional Park of Kaunas Lagoon, Dubrava Minor Reserve. For the lesson we will need such tools and materials: test-tubes with stand, glass stick, flask, funnels, test-tubes with cork (best with scale on it), pipette with scale, universal indicators and device for measuring of substrates pH. We will need: distilled water and 1 normality sodium chloride soak made in laboratory. In first case we will use distilled water and filtrate of soil. In second case we will make reaction of soaps with soil substrate soak and 1 normality sodium chloride soak. And in third case we will measure with pH device. Students will bring together in the tables and will compare those. One more way of pH determination is phytoindication. There are plants that are growing in acidic environment and precisely in bogs. Made 1 normality sodium chloride soak. Pour tomato juice in test-tube. And we calibrate our pH measurement device for 4 pH that it could recognize acidic soaks. We will dip pH measurement device in the acidic soak. Congratulations coming to Dubrava Minor Reserve. To what geographical type it could be assigned for? Bogs, you are saying right. And today we will have to make chemical tasks. The thyme of our lesson is determination of soil pH. Now I ask you all to remember what is pH? The scale which shows acidity of soaks. The soaks can be acidic, neutral and base. What environment is considered as neutral? 7 pH. Yes, 7 pH. And the scale is from 0 to 14. Acidic environment is from 0 to 7. And base? From 7 to 14. So today our aim and task is related to measuring of pH. And we will get such tasks. Using really simple chemical materials, indicators (some of the we made before by ourselves and others we got ready to use). We will have to make a research of soil pH in different places. How to make that we already discussed, we have plan and scheme of tasks. And now divide in 3 groups. We will use universal indicator, made from paper. And also pHmeter which we also dip as paper indicator in soak. And it will show the pH in the screen. And we will compare what shows the paper indicator and pHmeter. Everybody mark the result in your table. Today you mark those with pencil in your tables that we prepared. Taking the samples of soil. Sieving through 1 mm diameter sieve. Mix substrate with: A. distilled water. B. 1 N NaCl soak. Filtrate mixtures that was made. Determine pH of soaks with universal indicator. Write results in the table. Determine pH with the divice. Between 5 and 6 pH. Comparing the results. Between 5 and 6. That shows our indicator, the same shows the device. So we checked, environment is acidic. Plants og bogs: acidic environment phytoindicators. Operator, montage and participants

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