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Project title or topic of activity

Pond Science


Author(s): Jennifer Lamkin, Pricilla Ornelas, Muy Taing

Date: Spring 2000

 

Summary of Activity
50-100 words

Pond Science teaches students about freshwater ecology through visiting a pond and then creating ponds in the classroom. The activities include visiting a pond, collecting organisms, viewing them under a microscope, performing simple chemical tests, and finally creating ponds in the classroom. Each activity will allow the students to become familiar with ponds and water as a habitat and as a working ecosystem. The students will learn to utilize the scientific method during the activities. Throughout the activities, the students will keep a journal, including in it observations of the pond environment, physical characteristics of the water, and drawings of plants and animals in the pond. After examining the water and organisms under the microscopes, students will compare what they saw, and use it in a creative writing activity. Finally, by looking at the water quality data and variety of organisms collected, the health of the pond will be discussed and connected to the overall theme of water pollution and conservation. The samples collected will be used to reconstruct aquarium ponds in the classroom, and the class will be able join the adopt-a-pond online project.

 

Grade levels

This activity is appropriate for 6th through 8th grade levels. The optimal class size for the activity is 25 students, but it could be done with 20 to 30 students.

General description or introduction
The scientific principles that the activity is founded on.

Pond Science allows students to develop their knowledge of the scientific method as well as freshwater ecology. The activities presented will allow students to become scientists and use observation skills, questioning, and data collection to come to a conclusion about the ecology of a local pond. The creative writing microscope activity allows students to connect science to other subjects in a unique manner. Creating aquariums in the classrooms as small groups allows them to use what they have learned throughout the project to create a mini-ecosystem. The students must decide what organisms will go into the pond, and how many of each organism should be added. These ponds can then be monitored to "ecosystem design" is most successful. The most successful pond is the pond that is self-sustaining for the longest amount of time. However, success could also be measured by the number of organisms in the pond after a certain number of days. Pond Science is a fun, hands on learning experience that brings nature into the classroom.



Background information

Earth is the only planet known to have running water. In fact, over 70% of Earth is covered by water. All of this water is filled with life. Water is the habitat for a diverse range of flora and fauna, as well as many complex ecosystems. These ecosystems can be found in all types of water including lakes, rivers, streams, ponds, oceans and seas.

Ponds: Ponds are great for studying fresh water ecology since they are located everywhere and are usually small enough to be able to monitor easily. Ponds, like other isolated fresh water communities are composed of stagnant water. Though the water is considered fresh, it has a low ion content, the majority of which is salt. The water also tends to have suspended particles, which can give the water a murky appearance. Ponds tend to be small, shallow bodies of water with sunlight penetrating all parts. The pond environment is suitable to many different organisms. Pond life includes unicellular organisms, developing insects, plants and algae, fish (eggs and larval stages), snails, amphibians ( larval and development stages), worms, and many other organisms.

Each pond creates its own ecosystem, and in interesting to study due to the diversity of the organisms inhabiting the water. Creating ponds in the classrooms allows students to use what they learn during the field trip and subsequent activities to solve the problem of creating their own ecosystem. This activity makes the students into scientists. To create a successful mini-pond, there must be the correct combination of organisms, amount of food, chemical balance, sunlight, and temperature.A pond creating activity is outlined below, and there are also many books available providing useful information on maintaining an aquarium.

Pollution: By studying ecological relationships, scientists have been able to show exactly how pollution affects wildlife. For instance, high levels of mercury and other poisons in bodies of water are harmful to inhabitants. Ecologists have discovered that warm-blooded animals use up to 90% of their food for staying alive and moving about. Only about 10% is used for fueling the animal’s growth. For example, if an animal containing a milligram of mercury is consumed by a larger animal, it retains most of the mercury itself because it cannot easily get rid of it. However, the amount of weight the larger animal gains is only one-tenth of the smaller animal’s weight. So the mercury becomes much more concentrated as you move up the food chain. This process is called bioaccumulation or biological magnification.

A pH reading is a simple test that can indicate the quality of the pond water. Typically, ponds have a pH of 6.5 to 9.0. pH levels can change due to the acidity of rain and run off entering the pond. Acid rain is typically considered to be rain with a pH of 5.0 or less. The effect of acid rain can range from unnoticeable to almost total destruction. Some acidity of rain water is caused naturally by volcanic eruptions and lightning strikes. Dissolved CO2 in rainwater can cause a pH of 5.6. However, the type of acid rain that makes news is caused by humans.

A lake or pond affected by acid rain may have a pH of 4.5 to 6.0. A pond can usually maintain a pH flux between 6.5 and 7.5 with little stress to plants and animals. If the pH falls to 6.0 or below, a noticeable reduction in abundance of snails, amphibians, crustaceans, zooplankton, and fish occurs. Many insects and rotifers will be unaffected, while some amphibians, especially eggs, will be severely affected by even a small pH change. A pH of 5.0 will kill most organisms. Furthermore, when the pH of a pond becomes low, the effects of metals, storms, and toxins, may become more pronounced, making their devastating effects even more so.

The Scientific Method: The scientific method is used by scientists conducting research and experiments. Part of the pond science lesson is to allow the students to familiarize themselves with the scientific method. For the purpose of this lesson, the scientific method has been broken down into five simple parts. The parts are observation, question, experiment, data/results, and conclusion. Students make observations of whatever is being researched, in this case the pond. They use these observations to formulate questions. What each student thinks the answer to the question is becomes his or her hypothesis. An experiment is then set up to test the hypothesis and determine if it was correct or incorrect. The data and results collected are the evidence that answer the question being researched. Finally, a conclusion is made about the questions being asked. The conclusion usually includes whether or not the hypothesis was correct, and what the outcome of the experiment actually was.

Keeping a journal is important to this process, since the student will be able to refer back to what he or she has done and try and determine what was right, what was wrong, and exactly where any error in the results came from.



Credit for the activity
.

This lesson plan was originally done by Betty Moore, Fall Semester 1999. Information for the lesson plan was taken from http://www.yale.edu/ynhti/curriculum/units/1992/5/92.05.07.x.html. Additional ideas were taken from http://www.csis.pace.edu/schools/mv/bjackson/ourclasspond.htm, which contains information about pond science and allows classrooms to adopt a neighborhood pond and put it on-line, so that it can be compared to other ponds around the country and the world. This site also contains a simulated pond, which could be useful to test pond ideas before setting up the ponds in the classroom. Dr Mangin provided the information for collecting pond species around Tucson, and also suggested the earth ball activity. References used in creating this project include: Horne A. and Goldman C. Limnology 2nd Edition. McGraw-Hill Inc. 1994. Taylor C. and Pople S. The Oxford ChildrenÕs Book of Science. Oxford U.P. New York, 1995.


Estimated time to do the activity

Field Trip: 3 hours plus transportation
Microscope Activity: 60-90 minutes pH tests 30 minutes
Set up of ponds: 60-90 minutes Discussion: 60 minutes On-line pond (optional): 30 minutes



Goals of Activity:

Goal A
Utilize the scientific method through activities.



Goal B
Improve use of both dissecting and compound microscopes.



Goal C
Set up aquariums in classroom in small groups.



Goal D
Discover what types of life are found in ponds and discuss the pond ecosystem.



 

National Science Education Standards. (NSES)

Two content standards that this lesson plan covers:

Standard 1
Diversity and Adaptations of Organisms Pond Science meets this standard with the collection of organisms at the pond site and the microscope activity. While at the pond site, students are asked to collect ten different organisms. Collecting these organisms will give them an idea of the diversity of the pond. Using the microscopes will allow the students to view organisms that they cannot see with their eyes. The microscope activity will help the students see just how far diversity extends within pond life. The microscope activity will also allow the students to see adaptations of organisms. The students are asked to draw the organisms they see, and not special adaptations. The students are also asked to predict how the organism functions as an individual and also in the ecosystem based on these adaptations.



Standard 2
Develop descriptions, explanations, predictions, and models using evidence In Pond Science, the students keep journals to write down descriptions of organisms and the environment. They gather evidence to predict whether or not the pond is healthy. The students also use their findings in a discussion after the experiment to explain what was found. All of this information is then used by the students to create a in classroom mini-pond. In creating the pond, students use the information collected to predict what makes a pond successful, and then they built a model to test their hypotheses.



 

Materials Needed

Aquariums or large bowls gravel large rocks and screen (for covers if desired) Various habitat material of your choice (live plants, wood, etc.) Collected samples from local pond (or store) Microscopes (slides) Magnifying glasses (hand lenses) small vials for collection containers for water containers for larger animals and plants litmus paper lemon juice distilled water ammonia thermometer journals pencils blow up earth ball, or the earth part of a globe



Preparation

Engage: Initiate discussion about fresh water ecology by completing this pollution activity as a class. This activity is to show the effects of pollution in a body of water and wildlife. The materials required are one gallon glass jar, a measuring cup (250ml), and red food coloring. The first step is to pour a half cup of water in the gallon jar. The second step is to add two drops of red food coloring. The third step is to add one cup of water at a time to the jar until the red color disappears. It should take seven cups total to make the water clear. The red color is visible at the start of the experiment because the molecules of red food coloring are close enough together to be seen. As more water is added to the jar, the molecules of the red food coloring become further apart and invisible. Materials that are visible initially at one spot in a pond or a steam will eventually become invisible as it mixes with more water. This doesnÕt mean that the material is gone from the water. Animals can drink the water and they can be affected. This activity will allow students to start thinking about the overall theme of conservation and other ecological issues.

Preparation: Obtain materials needed for collection of organisms and water at the pond site. Obtain materials needed to create the classroom ponds. Though some will be collected at the pond, it may be necessary to purchase gravel, small fish, etc. from a local pet store. Make copies of the treasure hunt worksheet. Collecting animals and algae for the aquaria from local sources: Schedule a field trip to a local pond, stream, small pool, swamp, or lake. For the Tucson area, You can collect in streams in any number of canyons in the Catalina mountains. For example, Sabino and Bear Canyons, Pima Canyon, and Fingerrock are all good sites. Go in the spring after it has warmed up and insects are flying so that you can find aquatic insects and other insect larvae in the streams and stagnant pools associated with the streams. For example, very fun insects for tank are the yellow spotted predaceous diving beetles and whirligig beetles. Both of these eat fish food. In the canyon streams, near Tubac, or at Empire Ranch Cienega, you can find giant water scorpions - these are very active and interesting in aquaria, however, you must provide them with fish or live insects (e.g., flies) for them to eat. Another good source of aquatic insects is cattle tanks. If you are very lucky, you might find a giant water scavenger beetle; cattle tanks or other stagnant, algae-filled ponds are a good spot to find these. They are the size of very large cockroaches, but with better personalities. They eat algae (or lettuce) and will actively graze while you watch them in your aquaria. Sewage ponds do not tend to have many insects or larvae; neither does aqua caliente spring in NE Tucson. Anywhere there are lots of fish, there will not be many insects - the fish eat them!



Step-by-Step Procedure for the Activity

I. Earth ball Activity
1. As a fun starting activity, have the students sand in a circle and throw a inflated earth ball to each other. As each student catches the ball, have them look where their right index finger is pointing on the earth. Is it on land or on water? Use the numbers to calculate the percentage of water on the each. Divide the number of students that are pointing to water by the total number of catches. This will be the percentage of water. The percentage should be around 75%. This activity will help students realize how much of the earth is water. This activity could also be extended, by having the students that are pointing to water decide whether it is fresh or slat water, and then calculating the percentages of each.

II. Start a scientific journal
1. Each student should have his or her own journal to write down all observations, hypotheses, and data collected.

III. Collection of organisms and pond water
A. Field trip to pond
1. Divide students into small groups to collect plants and animals. Make sure each group goes to a different location around the pond, i.e. sunny, shady, etc. Each group should record in their journals, the appearance of the site, a description of the environment around the site (including trees, grass, shrubs, etc. and their distance from the water), any pollution nearby or sources of pollution, the clarity, the turgidity, the temperature, as well as the presence of algae on the surface and at the bottom of the pond. 2. Each group should find plants and/or animals to fill out their pond Treasure Hunt sheet. A sample sheet is provided below. Animal or Plant (common name) Location Observations 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Possible species for collection include insects and larvae, tadpoles, algae, plants, small fish, worms, leeches, etc. Collected specimens will be put into vials (with water) for later observation and identification in the classroom. 3. Between five and ten students will be given gallon jugs to collect pond water for testing and to be used in classroom aquariums.

IV. Observe water samples under dissecting and compound microscopes
1. Look at organisms under the dissecting microscope. Students should from small groups (two to three) Students should draw what they can see. Students should attempt to identify the organism generally as eggs, plants, worms, other animals, etc. While looking at the organism, they should answer questions in their journals. What role does the organism play in the ecosystem? How does it function individually? What adaptations does it have? How many are there? 2. Look at organisms under the compound microscopes. The students should remain in small groups. The students should draw a variety of unicellular organisms. The students should attempt to identify the organisms using the same general guidelines. The students should also try to answer the questions above, as well as comment about the variety and abundance of the organisms. Was it more or less than expected? 3. Have each group show some of their drawings to the class. Students should say what they found, their observations, and also what area of the pond the organism was found in. 4. The teacher can describe what was found and add more information while the students are presenting their findings to the class. 5. Creative activity. Students can do this activity individually. Each student should pick an organism that he or she saw under the microscope that hasnÕt been observed previously. First allow students time to list adjectives, verbs, and adverbs that come to mind. In a poem or short paragraph, the students should compare their organism to something. It should be something that they know, so that a new object can be related to an old one. This activity will encourage creativity and writing skills.

V. Learn about pH and test the pH of the water collected.
1. Students will form small groups to learn about pH if they have not already. Students will use litmus paper to test the pH of an acid (i.e., lemon juice) as well as a base (i.e., ammonia). Each group will then make a hypothesis about the pH of the pond water. The pH of the pond water will be tested, along with the pH of distilled water, so that the two samples can be compared. The hypothesis and results will be recorded in the journal and will be used as a basis for the discussion of the health of the pond, and how the pH affects the living organisms. 2. Each group can be given a pH chart, to compare the pH of the pond water to the pH of other liquids to give them a better perception of pH. A pH chart is provided below. Strong Acid 0 Stomach 1.0-3.0 Soft Drinks 2.0-4.0 Lemon Juice 2.2-2.4 Vinegar 2.4-3.4 Cider 2.9-3.3 CowÕs Milk 6.3-6.6 Drinking Water 6.5-8.0 Eggs 7.0-8.0 Washing Soda 11.0-12.0 Quick Lime 12.4 Strong Base 14

VI. Discussion of the health of the pond ecosystem
1. Observations on the amount of pollution seen at the site, the clarity, and the pH information will be important in the discussion. Pollution indicators may include: trash at the site, trash in the water, pH below 6.5, location of the pond; is it near a factory, in a city?. Also, if organisms collected have been identified, the presence or absence of some organisms will also be an indicator of the health of the ecosystem. For example an abundance of algae nay indicate high levels of nitrogen, small or undersized organisms may mean water is not healthy, some insect larvae typically develop in more polluted water: if they are present, what conclusions can be made?.

VII. Creation of the classroom ponds.
1. Students form small groups, size depending on the number of aquariums or large bowls. 2. Each group will search for organisms and water samples at different designated areas of the pond. The type and quantity of organism added should be recorded in the journals. 3. Fill the base of the tank with aquarium gravel that has been rinsed well to discourage algae growth (mud samples can also be added to the bottom of the aquarium.) 4. Use rocks, pieces of dead wood, to create an underwater landscape and surfaces for snails to feed on, for example. 5. Add enough water to fill the tank to about half its depth. Overfilling the tank may reduce the amount of oxygen that is dissolved in the water. Water collected from the pond can then be added to the tank (this will allow the introduction of tiny animals such as daphnia. Add rooted plants in pots. The plants should be covered, but the water does not need to be too deep (1/2 to 3/4 full). Essential oxygenating plants, such as floating pond weed, can be left to float freely 6. Finally, insects, fish, bugs, and whatever other organisms have been chosen can be added. If the ponds need to be covered, a screen can be placed on as a lid, and secured with rocks. 7. Place the tanks in bright light, but not direct sunlight. The plants in the tank will grow and provide the food needed by the organisms. 8. Students should continue to observe the ponds, and record observations in their journals. During their observations they should look for changes occurring. Have any organisms disappeared? Have any new organisms appeared.? Has the abundance of specific organisms changed? The groups can compare their ponds to see the success of different models.

VIII. Join On-line pond project
1. Visit the internet site www.csis.pace.edu/schools/mv/bjackson/ourclasspond.htm. Follow the directions provided to enter information about the pond studied. There is also information about other ponds that have been adopted by classes around the world.



Images, work sheets, additional web pages

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Items for discussion or conclusion

1st question

How does the pond ecosystem function and how does it compare to other ecosystems?


2nd question
Was the diversity of the pond greater then expected?



3rd question
Why is important to monitor pollution in ponds and other bodies of water?



4th question
What is the purpose of keeping a journal, and what did you learn from it?



 

Conclusion
The best concluding activity for Pond Science is the set-up of the classroom ponds. In setting the ponds up, the students must use the knowledge they have gained throughout the procedures. Setting up the ponds in small groups is a great way for the students to compare what they think will be successful. Thus, they can learn from each other. The ponds will be able to be monitored over time, so the students will be able to see the results of their predictions. By reviewing and perhaps grading their scientific journals, you can see if the students have utilized all the parts of the scientific method throughout the procedure. Also, the drawings in the journal will help to show whether the students have been successful with the microscopes. Is the drawing an actual organism or is it a blob on the lens? Another concluding activity is simply the discussion of what the students found. Students should be able to discuss what types of organisms were present and how they function in the ecosystem. This discussion can be extended to many other ecosystems. Students could hypothesize about the components that make other ecosystems function. A great starting place would be to discuss the environment in which the students live.



Beyond the Activity
Further activities which relate to and extend the complexity of the experiment.

Have students present the outcome of their group ponds to the rest of the class. Have them identify what was right and what was wrong and suggest possible solutions to the problems. Have students design other experiments or research projects that could be done in small groups and presented to the class. Possibilities include: What does pond water look like under a microscope? How does temperature, light, food, oxygen, and/or pollution effect a pond? How to insects develop from eggs to adults? How do amphibians develop from eggs to adult?



Web Resources
A web address with information on the topic of the activity.

Web Address
www.yale.edu/ynhti/curriculum/units/1992/5/92.05.07.x.html



 
Additional References

Reference
Taylor C. and Pople S. The Oxford ChildrenÕs Book of Science. Oxford U.P. New York, 1995.