Barium Sulphate Ph Testing 4j3g18

Soil PRACTICAL - Measuring pH using barium sulphate Soil may be acidic, neutral or alkaline and this practical allows us to find out which. Soil pH is very important because certain plants will only grow successfully in soils of a certain pH. For example heathers will grow successfully in acidic soils whilst carnations will grow well in alkaline soils. Most plants will grow well in neutral soils. APPARATUS Soil sample Universal indicator Test tubes pH scale

Barium sulphate Distilled water Test tube rack

METHOD 1) Use a spatula to put a small amount of barium sulphate into a dry test tube. It should be dry to stop the powder from sticking to the side of the tube. 2) Add a small amount of the soil to be tested (again using a spatula). 3) Use distilled water to fill the test tube to around ¾ full. 4) Add 5-6 drops of Universal indicator. 5) Put a bung in the tube, shake it well and allow to stand for short time. 6) A clear coloured liquid will be left in the top of the tube. This can then be compared with the pH chart to find the pH of the soil being tested. RESULTS TABLE Sample

Colour

pH