Question : To check the pH of tap water and compare it with pH of the water in the local water body. Apparatus : Test tubes or beaker Materials : Universal pH indicator / litmus paper Procedure : impliesTake water sample from tap of your home in a test tube. impliesAdd few drops of the universal indicator into the test tube containing tap water. implies Observe the water sample in the test tube for colour change. impliesTest pH using a litmus paper, in the water sample placed in a beaker. impliesDip the litmus paper into the water in the local water body. impliesObserve colour changes of the litmus paper. Observation : implies Test tube containing tap water, turns yellow colour with addition of pH indicator. implies Litmus paper does not show colour change with tap water. impliesWater sample collected from pond shows red colour with pH indicator. Litmus paper turns red as it is dipped in water of local water body. Conclusion : The uncontaminated tap water is neutral while water of local water body is acidic. What is the cause for acidic water in water body?