Collect Water from Two Different Water Bodies Around You and Study Them for ph Clarity and Presence of any Living Organism

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How is pH Important to Living Organisms Answer Key

The physical qualities of water include temperature, colour, taste, odour, etc. these qualities are determined by touch, sight, smell, and taste. For example, we can check the temperature by touch, colour, floating particles, turbidity and suspended solids by sight, and taste and odour by smell. Our goal here is to study different water bodies for pH, clarity and the presence of any living organisms. Water forms about 75 % of the earth’s surface. It is vital for all forms of life. Water is the habitat for many aquatic organisms. Here, we will focus on the study of the pH of different samples of water

In water, you will find many kinds of living organisms; some are visible to the naked eye while some may be microscopic. Sometimes you will also find suspended particles, a variety of plants and algae which have unique qualities to survive in water. Some conditions that control the quality of water are different types of plants, animals and their population, the turbidity of the water, and the pH levels of the water. Let us study an experiment by exploring different types of water bodies for pH, clarity, and presence of any living organisms. 

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Aim: To Study pH, Clarity, and Presence of Living Organisms in Two Different Water Bodies

1 - Aim: To study pH in two different water bodies 

Apparatus: Secchi’s Disk, Tape, Pins, Universal Indicator solution, dropper, tile, pH, beaker, test tube, coverslips, filter paper, glass slides, needles, and compound microscope. 


1 – Collect water samples from two different sources of water. 

2 – Dip individual pH paper strips into the two water samples. 

3 – Keep the stripes on the tile and let them dry. 

4 – pH levels can also be found by using universal indicator (UI) solution. 

5 – Drop 5 drops of UI solution in a test tube containing water samples. 

6 – Note the change in colour and compare with the colour chart. 

2 – Aim: To study Clarity or Turbidity in two different water bodies 


1 – Reach the middle of a pond in a boat.  

2 – Immerse Secchi’s disk into the water, lowering it until the black and white segments are no longer visible. 

3 – Mark the length on the rope where the disk is not visible with a pin. Mark this position as A. 

4 – With care, bring the disc back up and mark the length of rope where the disc becomes visible again. Mark this position as B. 

5 – Use a meter tape to measure the length of the section from A to B. 

6 - Now, find the mean length of the rope by using X = (A+B)/2. Fig.1

3 – Aim: To study the presence of living organisms in two different water bodies 

1 – Collect water samples from a pond in the test tube. 

2 – Leave the water undisturbed, till sediments settle at the bottom. 

3 – Put a drop of water from the test-tube onto the glass slide. 

4 – Slowly, place a coverslip on the slide using a needle. 

 5 – Now, observe the slide under a compound microscope.  Fig1.a

What is Turbidity of Water? 

Turbidity is a measurement to indicate the presence of suspended particles: more the particles, higher the turbidity. Turbidity is a measure of how cloudy the water is- it is also known as the clarity of the water. The sediments or particles are usually clay, silt, fine organic, and inorganic matter, soluble coloured organic compounds, algae, and other microscopic organisms.

An electronic meter is in use to measure low turbidity level changes. Turbidity is measured in NTU (Nephelometric Turbidity Units.)   

Importance of pH for Living Organisms 

Water with pH that is too low or too high can be harmful to fish and other aquatic life. At low pH, toxic metals such as aluminium can enter the water in higher concentrations. Some nitrogen-carrying chemicals become more harmful, and the metabolic processes of fish can work at less efficiently. Water with pH below 5 can inhibit reproduction or lead to death, and young fish and other aquatic organisms are easy victims. Water with a pH below 6.5 can hinder growth.

At high pH values above 9, most ammonium ions are converted to ammonia, which is toxic to fish. This problem gets worse with higher temperatures. Water with a pH between 9 and 10 will tend to inhibit growth, and water with a pH of 11 or higher will kill fish.

FAQ (Frequently Asked Questions)

Q1.What are Normal pH Levels?

The pH is the count of free hydrogen and hydroxyl ions in an aqueous solution. Solutions with a pH less than 7 are taken as less acidic and with a pH level greater than 7 are basic or alkaline. The normal level of pH for pure water is 7 at 25°C. 

Plants do best in the pH range of approximately 6.0 to 7.0. But, some plants may prefer more acidic or alkaline conditions, such as blueberries (4.0 to 6.0) or hyacinth (6.5 to 7.5). 

The pH range of 6.5-9 is best for most of the fish. In aquariums, the water is supplied with bicarbonate and carbonate ions to prevent pH changes.

Q2.  What is the Importance of pH for Soil?

Under acidic conditions, many minerals in the soil become soluble such as toxic aluminium. Useful phosphorus and molybdenum are less available at lower pH values. In alkaline (basic) conditions, the land can become deficient in zinc, copper, iron, manganese, boron and phosphorus.

pH is a necessary quantity that reflects the chemical requirements of a solution. The pH factor can control the availability of nutrients, biological functions, and microbial activity, and the behaviour of chemicals or control the pH of the soil, water. In Agriculture and gardening, different factors are affected by soil pH, such as microbial activity, fungal growth, availability of nutrients, and root growth.