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WATER QUALITY

UNDERSTANDING EARTH SYSTEMS WATER SYSTEMS

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PREDICT

OBSERVE

EXPLAIN

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POWERFUL pH

PREDICT

OBSERVE

EXPLAIN

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FRESH WATER

VINEGAR �+ WATER

BAKING SODA

+ WATER

PREDICT

P

PREDICT

OBSERVE

EXPLAIN

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acidity of a solution is measured using pH

measured the concentration of hydrogen ions in a solution

PREDICT

OBSERVE

EXPLAIN

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PREDICT

P

IF/THEN STATEMENT

IF…

If we use a pH test strip to test each of the 3 solutions,

THEN…

then the �pH of each will be ????.

PREDICT

OBSERVE

EXPLAIN

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FRESH WATER

VINEGAR �+ WATER

BAKING SODA

+ WATER

OBSERVE

O

PREDICT

OBSERVE

EXPLAIN

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FRESH WATER

VINEGAR �+ WATER

BAKING SODA

+ WATER

BASIC

#11

NEUTRAL

#6

ACIDIC

#1

PREDICT

OBSERVE

EXPLAIN

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EXPLAIN

E

  1. Which solution had the highest (most basic) pH? Which had the lowest (most acidic) pH?
  2. How did the pH of the plain water compare? What does this tell you about the tap water in your area?
  3. Why is measuring pH important?

PREDICT

OBSERVE

EXPLAIN

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WATER QUALITY

  • we test the water quality using a variety of measures
    • understanding the quality of the water around us is important for maintaining health

MRSTAV

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METHODS OF TESTING

  1. Turbidity
  2. Temperature
  3. Acidity
  4. Salinity
  5. Dissolved Substances

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TURBIDITY

    • the less turbid a water sample is, the cleaner it is

is a measure of the clarity of a water sample

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TURBIDITY

    • turbidity is measured by lowering a two-coloured disc into the water column and recording the depth at which the colours can’t be made out anymore
      • the deeper the disc can be lowered, the less turbid the water

is a measure of the clarity of a water sample

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TEMPERATURE

    • thermal pollution occurs when human activities artificially increase the temperature of a water body
      • e.g. thermal pollution occurs around nuclear power plants, which return warm water to water bodies and raise their temperature

the warmer the water, �the less dissolved oxygen it can hold

  • dissolved oxygen is essential to �aquatic life

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ACIDITY

    • acidity is determined by measuring the pH of a sample
      • pH values range from 14 (very basic) to 1 (very acidic)
        • distilled water (containing no other substances) has a neutral pH
      • the higher the dissolved hydrogen, the lower the pH

measures the concentration of dissolved hydrogen �atoms in a water sample

dissolved hydrogen can come �from chemicals such as sulfuric �acid and nitric acid

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SALINITY

    • salt water is a good conductor of electricity, so we check for the presence of salt by checking if the sample will conduct electricity

the salinity of a substance tells us how much dissolved salt is present

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DISSOLVED SUBSTANCES

examples:

      • chlorine – added to kill unwanted organisms in treated water
      • nitrates – found in fertilizers
      • iron and copper – dissolved from rocks or older piping
      • calcium and magnesium – dissolved from rocks (makes water hard)

other substances can be present in water samples because of contamination or because they are added as part of the water treatment process

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  • Turbidity
  • Acidity
  • pH
  • Contamination

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