Lesson Plans
My students are second graders and just beginning to learn about the wonders of the world. I want them to be positive about their surroundings and to develop a harmonious integrative attitude toward nature. But, at the same time there is an urgent need to make them aware of the very real threats to the lives of the earth's fauna, and by association humanity.
One objective included into the second grade science curriculum is to become familiar with the concept of food chains and webs. The idea is to make the students aware of the interconnections that sustain and maintain balance in the natural world and to recognize how the sun's energy flows from plants through the animals that consume them on to the first and second level carnivores. When we present these lessons we often ask student to consider what would happen if a given animal or plant was removed from the chart. All too often the children chime out "they would die". Now, I realize that some people feel that death is the ultimate threat.
But, starvation, malformation and other impediments can make life pretty grim. I want my students to consider some of the difficulties that some creatures have during their lives. Therefore, I intend to introduce them into the realization of how many of our animals are facing the threat of extinction. Among them I want to discuss: otters, sea gulls, polar bears, blue herons, and alligators.
Just a couple of weeks ago one of my little students was looking at the pictures in a National Geographic Magazine. I saw the look of distressed fascination on her face and walked over to see what she was looking at. It was the picture of a young child whose eyes were fused together. My student wanted to know why that was. I read the caption out loud to her and then had to explain that the birth defect this child had was probably due to some form of poisoning that her mother had undergone while she was being formed. Our discussion attracted the rest of the classmates who wanted to see for themselves what we were talking about.
The discussion gave me the opportunity to point out that some plastics leach their chemicals into the liquids or foods within them. Puritanically I pointed to my glass beaker that I keep with my drinking water and told them that I was wary of the chemicals within, so preferred to use glass. Next morning many brought their drinking water in glass bottles. Will there be accidents? I daresay yes. But they will also learn to be careful.
Lesson I
Such an introduction to plastics was unintentional. However, it is useful and I might replicate the episode for future use. We will discuss the usefulness of plastics, the benefits of having them as well as their chemical compositions and lack of biodegradability. This week long lesson will probably be taught in the spring semester as it is then when the curriculum includes biology (life science).
As the children become aware of the permanence of these synthetic chemicals we will try to follow a molecule through a food web (much as the one that Colborn et al described) and discuss how it is affecting the host biota's ability to reproduce. I believe that making a felt chart simulating a pond or lagoon wild life scene with felt mollusks, crustaceans, small fry, fish, herons, ducks, and perhaps raccoons will help bring the concept to bear.
Because my ultimate goal is for the students to grasp the idea of the dangers posed to the fauna, especially the top predators, I intend to expand the lesson to include a fairly complex mathematical concept: logarithmic increase. My plans for this lesson are to break my students into the pond fauna. The phytoplankton in the pond will bear the number 25. Fauna at the bottom of the pond will be marked with 50X. Those fish that prey upon the bottom feeders will be marked with 800X, the fish that eat those will be marked 2,800X and the top feeders: herons, or raccoons will be marked 25,000X. As predator consumes prey he or she will take on their numbers. The next predator will consume its prey acquiring all the numbers. The top predator will, of course, acquire the greatest number.
Once the top predators have eaten the second level consumers we will take up the numbers and add them up. Then I will begin a discussion about what the numbers represent (concentrations of PCBs) and how it is that the most endangered of the animals are the most affected by the chemicals from plastics. We will look at the polar bear, the dolphin, sea gulls, blue herons, and alligators again and discuss their respective niches.
At this point I would have the students choose one of these top predators and ask them to read some books (previously collected in the classroom for the purpose) about them. When they have read enough I will have the students draw the ecosystem in which their animal is top predator. As they finish their drawings we will repeat the question above "What will happen to the ecosystem if your animal is gone?"
After a brief discussion I would form groups of three or four students and encourage them to discuss the possible effects of losing top predators. As usual, when they have finished their discussions I will invite the groups to the front of the classroom and have them present their conclusions to the class in general.
To end the sessions on the threat to the balance of ecosystems it follows that we will discuss steps to take in order to reduce the possibility of falling victim of the threat. Among the suggestions will be to use ceramic, glass or steel utensils instead of plastic ones. Another will be to stop buying prepared food products and encouraging their parents to buy and prepare fresh fruit and vegetables for their meals and drinks. Because my students are very young many are becoming siblings to even more vulnerable and defenseless creatures than themselves. It will be very important for them to suggest to their parents to reduce the amount of plastics to which their new babies can be exposed.
Lesson II
Another aspect of the plastics' saga that I intend to cover is the unfortunate Eastern Garbage Patch that collects in the North Pacific gyre. My purpose in introducing this subject is to develop consciousness about the natural world and our obligation to keep it clean and habitable for all the creatures on earth.
In preparation for units such as these the students will have previously learned much about maps: of the world, of the United States, an of course, Texas since that is where we live. Part of that learning includes water features such as rivers, lakes, seas, and oceans. The students have activities that show how rivers empty their water into the oceans along with sediments which will fall into the bottom, forming deltas. As a continuation of these lessons and as a way to introduce the Garbage Patches in the Pacific Ocean we will need to discuss trash and debris as part of the pollutants that are carried to sea.
Before the class I will fill a large transparent container with water (a twenty gallon aquarium will do). When the students are ready for their class I will take them out to pick up as much trash as they can from the school premises. After we have our materials on hand we will begin a discussion about how the rubbish got to the place where they picked it up.
When they have provided enough insight into the ways that garbage gets deposited I will ask them to pretend to be on a picnic near a river when a gust of wind picks up a paper plate and drops it in the water and is carried away by the stream. Some student will drop a paper plate into the water tank and the rest will observe what happens to the paper plate. They will record their findings in their science journals and provide explanations.
Then I will offer another student a plastic plate of the same size and ask the group what they think will happen to the plastic plate. After the students drops the plate into the water we will observe it. After a reasonable amount of time of observation the students will again record their findings along with their explanations. I am certain that there will be a few students who will want to disprove the findings, so I am prepared to allow them to investigate.
The following day we will begin the lesson with a conversation about which items in their garbage bags will float and which ones will sink to the bottom. We will write the opinions on the board and then dump the collections into the water watch. If everything goes according to plan the plastics will remain afloat while the other debris will eventually sink. After recording their findings and thinking about explanations we will see if their ideas were right.
The third day two students armed with hair dryers will stand on opposite sides of the water tank and, pointing toward the debris still floating will begin to blow air creating a gyre. As the students watch the rubbish float to the center they will be asked to think about the amount of sunlight that would be reaching the fish underneath the accumulated rubbish on the surface. Discuss what the marine fauna might think these floating bits of plastic might be. I will then encourage the students to consider what sea birds flying over head might think some of the floating bits of plastic can be.
I will them show the students pictures of the Pacific Ocean, the Pacific Garbage Patch and a map showing its size relative to the North American continent. These pictures will be followed by a short video from the following website: http//www.youtube.com. From it the students will learn what the effects of the plastic debris have on the fauna. The video includes information about bacteria and poisons collecting around the nurdles making them a greater source of poison for the creatures eating them.
After viewing the movie I will have the students collect the floating plastics in the tank and put them out to dry. The next day I will have the students form groups to discuss and plan effective posters to display throughout the school building. The thrust will be to discourage their peers from disposing of their rubbish in careless ways and suggesting effective recycling habits. The students will then begin to make their posters using the collected trash to drive their points across.
Lesson III
By the nature of the Pacific Garbage Patch the unit lessons above will be integrating Social Studies concepts as well as some in Science. The students will have learned about the threat to the health and future of different animals resulting from chemicals migrating out of plastics. They will have learned about air and water currents and their role in the collection of discarded plastics in the Pacific gyre and the threat that it poses to the environment at large.
It will be fitting then, when learning about the three bodies of government, to extend the portion about the legislature to include laws and regulations for the welfare of the people. We will discuss some regulations designed to ensure the health of the general population and the entities assigned to that duty: FDA and EPA. The students will then draw pictures that indicate their understanding of protective agencies. While the students draw I will begin a chart of the three systems which I will mount on the wall. Then I will place the words "Legislative Body" to the left of the large triangle.
The next day the students and I will discuss and review the legislative role in passing laws and regulations. I will then ask them who will validate these laws. I am certain that they will mention the police. Undoubtedly they will have many anecdotes to strengthen their opinions. But, I will ask them if they know what happens after the police "get you". Eventually we will be discussing the judges and their role in the judicial system - or body - of government. The words "Judicial Body" will be placed on another side of the triangle.
Since the purpose of this lesson is to make the students aware of discrepancies between intent and actual procedures I will direct their attention to the FDA' and EPA's roles and ask them into which body they might belong. Then I will place the drawings that the students made on the side of the triangle that they think those entities belong: the Judicial.
After placing the FDA and EPA on the chart the students and I will discuss the benefits that a plastics factory provides for the population: work for people, available money to spend for needs and wants; inexpensive products for the home; etc. The list could go on depending on the students' ideas: ideas that we will incorporate into a brain storming chart.
Then we will revisit the negative effects that those plastics have had on the ecosystem and the health of the wild animals, the laboratory animals and humans. Having added the negative consequences of the chemicals within those plastics on the brain storming chart the students will be asked to evaluate the benefits and the results. This will best be achieved by having them break into discussion groups.
When they have finished discussing their thoughts they will present their conclusions to the rest of the class. Hopefully there will be some question about the efficacy of the FDA and the EPA in preventing, or at least, stopping the promulgation of the noxious chemicals.
Should they not do so I will have to mention it asking them how it came to be that the two groups that were assigned the welfare of the population could have failed so ignominiously. Second graders are very much aware that standards of behavior established by grownups can be systematically broken; especially when the grownups made the rules without really thinking them out or without the desire to enforce them. They will understand how those entities neither implemented nor enforce the regulations and laws.
The following day the students will be asked to offer explanations about what caused the break down in justice. Should I go on to chart the third part of the triangle and speak of the Executive Branch and its influence over the other two? Perhaps I will let it rest until the students are older….. or maybe I will equate government with big business and let the young ones begin to question our entire moral and ethical structure.
While I decide upon this thorny theme I will ask the students to write letters to the members of the Executive branch manifesting their feelings on the subject. When I have collected them and put them into corresponding envelopes the students will put down their pencils and closed their notebooks. Then they will begin to dance around the room chanting the following ditty:
"Children of the Sun
The time has come
To get together
To make the world better"
(Ram Bhagat)
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