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Total Dissolved Solids

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Total Dissolved Solids

    Test

     1 Temperature

    INTRODUCTION

    The temperature of a body of water influences its

    overall quality. Water temperatures outside the

    “normal” range for a stream or river can cause harm

    ? Air temperature to the aquatic organisms that live there. It is for this

    reason that the change in the temperature of the water ? Amount of shade over a section of a stream is measured, not just the

    temperature at one location. If the water temperature ? Soil erosion increasing turbidity changes by even a few degrees over a one-mile stretch

    of the stream, it could indicate a source of thermal ? Thermal pollution from human activities pollution. ? Confluence of streams Thermal pollution caused by human activities is one factor that can affect water temperature. Many

    industries use river water in their processes. The water is treated before it is returned to the river, but

    is warmer than it was before. Runoff entering a stream from parking lots and rooftops is often

    warmer than the stream and will increase its overall temperature.

    Shade is very important to the health of a stream because of the warming influences of direct

    sunlight. Some human activities may remove shade trees from the area which will allow more

    exposure toexposure tosunlightsunlightMediumLowLowHighsunlight to reach the water, causing the water temperature to rise.

Another factor that may affect water temperature is

    the temperature of the air above the water. The extent

    of its influence has a great deal to do with the depth of

    the water. A shallow stream is more susceptible to

    changes in temperature than a deep river would be.

    ? Solubility of dissolved oxygen While many factors can contribute to the warming of

    ? Rate of plant growth surface water, few cause it to be cooled. One way

    water can be cooled is by cold air temperatures. A ? Metabolic rate of organisms

    ? Resistance in organisms Water Quality with Computers 1 - 1

     Test 1

     Organism Temperature Range

    (?C) second, natural method of cooling a river or lake

    comes from the introduction of colder water from a Test 1 Trout 5 20 tributary or a spring.

    Smallmouth bass 5 28 One important aspect of water temperature is its effect

    on the solubility of gases, such as oxygen. More gas Test 1 Caddisfly larvae 10 25 can be dissolved in cold water than in warm water.

    Animals, such as salmon, that require a high level of Mayfly larvae 10 25

    dissolved oxygen will only thrive in cold water. Stonefly larvae 10 25 Test 1

    Increased water temperature can also cause an increase Water boatmen 10 25 in the photosynthetic rate of aquatic plants and algae.

    This can lead to increased plant growth and algal Carp 10 25 blooms, which can be harmful to the local ecosystem.

    Mosquito 10 25

    A change in water temperature can affect the general Catfish 20 25 health of the aquatic organisms, thus changing the

    quality of the stream. Table 1 lists the optimal

    temperature ranges of some selected aquatic

    organisms. When the water temperature becomes too

    hot or too cold, organisms become stressed, lowering their resistance to pollutants, diseases, and

    parasites. Expected Levels

    Water temperatures can range from 0?C in the winter to above 30?C in the summer. Cooler water in

    a stream is generally considered healthier than warmer water, but there are no definitive standards.

    Problems generally occur when changes in water temperature are noted along one stream on the

    same day. Some sample data are listed in Table 2.

    Temperature Temperature Site Season Season

    (?C) (?C)

    Hudson River, Poughkeepsie, Winter 5 Summer 25

    NY Missouri River, Garrison Dam, Winter 3 Summer 14

    ND Rio Grande, El Paso, TX Winter 16 Summer 21

    Mississippi River, Memphis, TN Winter 7 Summer 29

    Willamette River, Portland, OR Winter 9 Summer 22 Summary of Method

    You will use a Vernier Temperature Probe to measure the temperature of water at one site each

    week.

    1 - 2

    Water Quality with Computers

Temperature

    TEMPERATURE

     Collection and Storage of Samples

    1. Water temperature must be measured on site by either placing the probe directly in the stream or

    by collecting a sample and immediately measuring its temperature.

    2. If you need to collect a sample to measure on site, it is important to obtain the water sample from

    below the surface of the water and as far away from the shore as is safe. If suitable areas of the

    stream appear to be unreachable, samplers consisting of a rod and container can be constructed

    for collection.

    Pre-Testing Procedure

    1. Position the computer safely away from the water model. Keep water away from the computer at

    all times.

    2. Prepare the computer for data collection.

    3. Plug the Temperature Probe into Channel 1 of the Vernier interface.

    4. You are now ready to collect temperature data.

    a. Select a position on the model and place the tip of the probe into the water.

    b. Monitor the temperature in the Meter window for 30 seconds.

    c. If the temperature appears stable, simply record it on the Data & Calculations sheet and

    proceed.

    d. Select another position on the model and repeat a to c.

    Position Temperature 1 Temperature 2 Average

    (?C) (?C) temperature

    (?C)

    1

    2

Water Quality with Computers 1 - 3

Testing Procedure

     Test 1 1. Position the computer safely away from the water. Keep water away from the computer at all times.

    2. Prepare the computer for data collection.

    3. Plug the Temperature Probe into Channel 1 of the Vernier Test 1

    interface.

    4. You are now ready to collect temperature data.

     Test 1 a. Place the tip of the probe into the sample of Site 1.

    b. Monitor the temperature in the Meter window for

     30 seconds. Test 1 c. If the temperature appears stable, simply record it on

     the Data & Calculations sheet and proceed.

1 - 4

    Water Quality with Computers

Temperature

     Temperature- Create a classroom chart

    DATA & CALCULATIONS Stream or lake: ____________________________ Date: ________________________________

    Site 1 name: _____________________________ Time of day (Site 1): _____________________

    Week Temperature 1 Temperature 2 Average (?C) (?C) temperature (?C)

     1

     2

Column Procedure:

    A. Record first water temperature reading at site.

    B. Record second water temperature reading at site.

    C. Average the water temperature at each site = (A + B) / 2

Field Observations (e.g., weather, geography, vegetation along stream) __________________________

     _________________________________________________________________________________

     _________________________________________________________________________________

     _________________________________________________________________________________

    Water Quality with Computers 1 - 5

     Test 1

    ADDITIONAL INFORMATION

    Tips for Instructors

    1. Make sure your students are using the correct experiment file. Each type of Temperature Probe

    (see Table 3) has its own experiment file. For example, if you are using the Stainless Steel

    Temperature Probe, use the file named “Test 01 Temp-Stainless Steel”. Test 1

    2. Which Temperature Probe should I use? All of the Temperature Probes in Table 3 will work

    well for water quality studies. Additional information is listed to help you decide.

     Test 1

     Test 1 Stainless Steel Temperature Probe

    ? no calibration required

    ? auto-ID with LabPro ? excellent chemical tolerance

    ? Range: 25?C to 125?C

    Vernier Direct-Connect Temperature Probe

    ? excellent chemical tolerance

    ? 5-foot cable

     ? Range: 15?C to 110?C

    Vernier Extra-Long Temperature Probe

    ? 100-foot cable for doing depth studies

    ? good accuracy with calibration

    ? excellent chemical tolerance ? Range: 50?C to 150?C 3. In some studies, water temperature as a function of depth is useful information to collect. There

    are two ways to accomplish this. The best method is to use the Vernier Extra-Long Temperature

    Probe. It has a 30-meter cable that can lower the probe directly into the water and works very

    well for this purpose. If you do not have one of these probes, but do have a Water Depth

    Sampler, you can “grab” a water sample and

    measure it at the surface.

    4. The graph at the right shows the monthly

    water temperatures of the Cowlitz River in

    Kelso, Washington over a one-year period of

    time. This illustrates the magnitude of

    temperature change that can occur in the

    course of a year. A stream with less water

    flow than this river would be even more

    dramatically affected by changes in the

    weather, melting snow, or periods of high or

    low water flow.

5. The effect of water temperature on aquatic Monthly Temperatures, 1 - 6 Cowlitz River, Kelso, WA

    Water Quality with Computers

    Temperature

    organisms is actually very complicated. Not only does water temperature affect the metabolic

    rate of aquatic organisms as mentioned earlier, but it affects their feeding habits and

    reproductive cycles as well. Many animals also have different temperature requirements for

    different stages of their life cycles. Aquatic animals can usually tolerate slow, gradual changes

    far better than sudden temperature changes.

    6. If taking a reading one mile upstream is not practical, take the data from a second site as far

    upstream as possible. Note the approximate distance between Site 1 and Site 2 on the Data & How the Temperature Probes Work Calculations Sheet.

    Stainless Steel Temperature Probe

    This probe uses a thermistor to measure temperature. The thermistor is a variable resistor whose

    resistance decreases nonlinearly with increasing temperature. The probe is stainless steel making it

    very chemical resistant.

    Vernier Direct-Connect Temperature Probe

    This probe uses a temperature transducer to measure temperature. It produces a voltage output that ?varies in a linear way with temperature. The probe is covered with Teflon FEP heat-shrink tubing.

    This coating protects the probe from damage in most environments.

    Vernier Extra-Long Temperature Probe

    This probe uses a temperature transducer and an amplifier box to measure temperature. The

    transducer produces a voltage output that varies in a linear way with temperature. The probe is

    ?covered with Teflon FEP heat-shrink tubing. This coating protects the probe from damage in most

    environments.

    Do I Need to Calibrate My Temperature Probe?

    Stainless Steel Temperature Probe

    No. Calibration is not required with the Stainless Steel Temperature Probe.

    Vernier Direct-Connect Temperature Probe

    There is usually no need to calibrate the Direct-Connect Temperature Probe yourself. Using the

    temperature calibration stored in the experiment file will give excellent results. For greatest

    accuracy, however, you could follow the two-point calibration procedures described for the Extra-

    Long Temperature Probe.

    Vernier Extra-Long Temperature Probe

    Using the temperature calibration stored in the Logger Pro program will give satisfactory results

    with this probe. For greater accuracy, however, you could calibrate the probe yourself. To do a two-

    point calibration for a Temperature Probe, follow these procedures:

    1. Prepare an ice-water bath and a room-temperature bath:

    ? When preparing the ice-water bath, stir vigorously with a magnetic stirrer and use plenty of ice

    (crushed ice works better than ice cubes).

    Water Quality with Computers 1 - 7

    ? When preparing the room-temperature bath, make sure the water temperature has stabilized

    and use a high-quality thermometer.

     Test 1 ? Suspend the Temperature Probe with its tip in the ice region of the ice-water bath.

    2. In Logger Pro, choose Calibrate from the Experiment menu. Click .

     Test 1 3. Type “0” in the edit box. This represents the temperature value 0?C. When the displayed voltage

    reading for Input 1 stabilizes, click Keep.

    4. Move the Temperature Probe to the room-temperature water bath. Allow time for the Test 1 temperature to stabilize.

    5. Type the actual temperature, as read by the thermometer, in the edit box. When the displayed

    voltage reading for Input 1 stabilizes, click Test 1 KeepOK, then click .

1 - 8 Water Quality with Computers

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