Science Junction

 

Water What-ifs

Teacher Notes,
Lesson Extensions and
Alternative Assessment Ideas

Teacher Notes, Lesson Extensions and Alternative Assessment Ideas

Lesson 1-Introductory Lesson-Determination of Overall Water Quality Using a Macroinvertebrate Survey

1. This lesson may be done in the field or the lab, but the preference is as a field study because of the susceptibility of some of the aquatic organisms to environmental changes.

2. If samples are collected and brought back to the lab for the determination, they should be collected as close to time of use as possible. If they are going to be kept for a few hours before use, they should be aerated as some species of macroinvertebrates are extremely sensitive to changes in the dissolved oxygen levels.

3. The line drawings and diagrams which are found at the Macroinvertebrate Identification Chart link, may be printed out and laminated for use in the field or laboratory.

    Lesson 2-pH and Macroinvertebrate Populations-Do Changes in the pH Level Effect an Aquatic Ecosystem?

1. Aeration of the samples is preferable during the 24 hour period, because of the susceptibility of some of the aquatic organisms to environmental changes. The organisms which are the most susceptible are the ones which are intolerant to pollution. As the dissolved oxygen levels decrease, the organisms will rapidly die off. The dissolved oxygen levels begin to decrease almost immediately after the sample is taken from the water.

2. Reagents

1% NaOH

Weigh out 1 gram of NaOH. Add the NaOH to 99 milliliters of distilled water. Store in a capped bottle. Invert and mix before use. Put in labeled dropper bottles for use in this lesson.

1% HCl

Add 1 milliliter of 1M HCl to 99 milliliters of distilled water. Store in a capped bottle in an acid cabinet. Put in labeled dropper bottles for use in this lesson.

Note: Safety goggles and aprons should be worn at all times when mixing reagents. When working with acids, reagents should be made in a exhaust hood.

Lesson 3-Pesticides, Fertilizers and Macroinvertebrates-Does the Introduction of Pesticides and Fertilizers Alter an Aquatic Ecosystem?

1. Aeration of the samples is preferable during the 24 hour period, because of the susceptibility of some of the aquatic organisms to environmental changes. The organisms which are the most susceptible are the ones which are intolerant to pollution. As the dissolved oxygen levels decrease, the organisms will rapidly die off. The dissolved oxygen levels begin to decrease almost immediately after the sample is taken from the water.

2. Reagents

5% pesticide solution

Add 5 milliliters of a liquid pesticide to 95 milliliters of distilled water. Store in a capped bottle. Invert and mix before use. Put in labeled dropper bottles for use in this lesson.

Note:If using a granular type of pesticide, weigh out 5 grams and dissolve in 95 milliliters of distilled water.

5% fertilizer solution

Add 5 milliliters of a liquid fertilizer to 95 milliliters of distilled water. Store in a capped bottle. Invert and mix before use. Put in labeled dropper bottles for use in this lesson.

Note: If using a granular type of fertilizer, weigh out 5 grams and dissolve in 95 milliliters of distilled water.

Note:Safety goggles and aprons should be worn at all times when mixing reagents.


Lesson Extensions

1. Have students evaluate two different collection sites with different surrounding land uses. For example, compare an area which is surrounded by farmland and an area that is surrounded by a wooded tract. Have the students compare the results of their macroinvertebrate surveys. Do the surveys vary based on the surrounding land use? If so, why?

2. Storm drain stenciling to alert the public where the storm drains on their streets lead. Have the students conduct research to determine where the storm drains surrounding the school lead. Have them conduct a walking survey to determine what types of things may end up in the storm drain and eventually the waterways and what effect each item may have on aquatic organisms.

3. Have students who are interested in photography create a photo journal of water quality testing or a manual on how to do water quality testing using photos to explain the process.

4. Have students create a aquatic insect collection.


Alternative Assessment Ideas

1. Set up several different aquatic ecosystems. Have the students keep a daily journal of the changes which take place over a period of time.

2. Have student assess the quality of several different water samples and determine the types of macroinvertebrates which may be found in each sample.

3. Teach students to perform chemical tests such as dissolved oxygen and pH. Assess their ability to conduct these tests accurately by providing known samples for them to analyze.

4. Set up stations with different species of macroinvertebrates. As a timed activity, allow the students to work in pairs to identify the macroinvertebrates and describe their distinguishing characteristics.



Water What-ifs Home | Macroinvertebrate Lessons



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©1998 April J. Cleveland for Science Junction, NC State University.
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lessons/macro/macroteachernotes.htm
Last Modified: 7/27/00

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