Testing the water


1. Blue & red litmus paper (Can be obtained from any science supply store)
2. An eyedropper or just a dropper (Can be obtained from any pharmaceutical)
3. A cookie sheet
4. Some rain water (Place a cup on the rooftop during the rain to collect rain water)
5. Some tap water
6. Some pound water
7. Some distilled water (Can be obtained from any science supply store)


1. At first lay out the blue and red litmus paper on the cookie sheet.
2. Now use an eyedropper to place a drop of rainwater on each piece of litmus paper.
3. Write down any kind of color change you see. Wash and then dry your eyedropper after that.
4. Repeat the same process shown in instruction 2 for tap water, pound water and distilled water. Remember to wash and dry the eyedropper after every use.
5. Write down any kind of color change you can see.


Different water sample will change the color of the litmus paper differently.


Normally people assume that water has a neutral pH. But water can contain all sorts of different kinds of dissolved impurities that can change the pH of the water. For example, fresh water from the tap is often slightly basic. That means it can turn the red litmus paper into blue litmus paper. That’s because it can have a lot of dissolved carbon dioxide in it. If the sample from the tap wasn’t fresh, you might not have seen this effect. This is because as tap water sits it becomes more and more flat as the carbon dioxide leaves. The same effect occurs when carbonated soda is left out. Distilled water means water which was turned vapor at first through heat and then turned into liquid water again by cooling the vapor down. Through this process we can have close to pure water. That’s why distilled water has neutral pH and it doesn’t change the color of neither blue nor red litmus paper. Water from the pound can greatly vary its pH because of the impurities produced by nature and/or human. Rainwater normally turns the blue litmus paper into red litmus paper. So the rain water is on the acidic side. There are many pollutants and oxides in the air such as carbon dioxide. These pollutants and oxides get caught in the rainwater as it falls from the sky. Unpolluted rainwater has a pH of approximately 5.6 values. But pH values bellow 5 can be really very harmful for plants and wildlife.


1. Use the water from a swimming pool to see what happens.
2. Use the water from a public fountain in this experiment.
3. Use parking lot puddles water and observe.


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