Solid Waste and Recycling
by Jean M. Becker
Unit Overview
The focus of this unit is on the process of decomposition. It is designedfor a third/fourth grade class but can be adapted for use at higher or lowergrade levels. It is an integrated science unit designed to use and developskills and abilities in observation, recording, writing, reading, listening,speaking and thinking.
Prior knowledge includes a basic understanding of environmental issues suchas conservation and the concepts behind recycling, reducing and reusing.Students should also be familiar with life cycles of living things as wellas food chains and food webs. They should also have some knowledge of matterand how the different forms of matter change solids, liquids and gases.
Lesson One : video introduction
Objectives:
Students will identify, through discussion, the main ideas presented inthe video.
Time/Grouping:
40 Minutes, whole class.
Materials:
-Video, The Rotten Truth. Children's Television Network. Length: 30 minutes.
-Chart paper/markers
Procedure:
-View video.
-After viewing, ask students to identify the main ideas presented in thevideo and record it on a chart to use as a starting point for this unit.
-Encourage students to make connections with other related knowledge theyhave regarding the issues and information presented in the video. For example,the garbage problem, where it goes, how a landfill is constructed and maintained.
-For homework, students are to interview their grandparents or an olderneighbor or relative about what happened to garbage when they were children.
Lesson Two: K-W-L
Objectives:
-Students will identify information they already know about landfills orthe process of decomposition.
-Students will discuss landfills, the decomposing process (if they alreadyknow of it), life cycles/food chains/food webs.
-Students will identify questions or areas that they want to learn moreabout.
Time/Grouping:
10-15 minutes, whole class.
Materials:
-Chart for front of room with three columns: K (what you know); W (whatyou want to know); and L (what you learned - to be filled in as the unitprogresses or at the end).
-Markers for charts.
-Individual charts for students to keep track of the class list to put intheir science folders and to fill in as they learn or have more questions.
Procedure:
-Put chart up in the front of the classroom or in the discussion area.
-Identify main topic of decomposition refer to video and try to elicit keyconcepts from students to list a definition. Ask students to brainstormany/all ideas, experiences with the concept. Any response is acceptable.If response is way off base, discuss further to try to identify reasons.
Lesson Three: Decomposition Demonstration
Objectives:
-Students will observe the process of decomposition
-Students will set up a science experiment with a control and variables.
-Students will predict what will happen.
-Students will observe and record data.
-Students will formulate a conclusion based on their observations.
Time/Grouping:
40 minutes for introduction and set-up; approximately 5-10 minutes dailyfor observations of results; 30 minutes for whole group discussion of resultsand formulation of conclusions.
Materials:
-5 equal pieces of banana peel (per group)
-5 interlocking sandwich bags (per group)
-water
-yard or garden soil from outdoors
-labels and/or marking pen
-observation recording sheets
Procedure:
-Divide the students into small groups, 4-5 students per group.
-Go over the following procedure with the whole class first.
-Put an equal piece of banana peel in each sandwich bag. A discussion ofwhat equal means and how students could determine equal pieces is good here,brings in math, if time. Measuring, weighing or estimation is acceptable.
-Use all but one of the sandwich bags to test your variables (change thatmight or might not make the banana peel rot or disintegrate). Listed arefour possible variables, you could have more.
-Label each bag with variables selected:
-Water: Add enough water to one sandwich bag to cover the piece of sectionof the banana peel. Squeeze out most of the air. Seal the bag.
-Soil: Cover the piece of peel in another bag with yard or garden soil.Do not use potting soil from a bag. You need dirt with microbes in it. Sealit.
-Light: Squeeze the air out and seal the section of peel in another bag.Tape this bag (only this bag) to a sunny window.
-Air: Lots of air. Poke holes in the next bag. Leave it open to let aircontinually enter the bag.
-Control: Squeeze the air out and zip it shut.
Put all bags except the light one in a dark place. I usually place eachgroup's bags in a brown paper bag and label each group's bags.
-Observe and record data daily or every other day. This can be done in ascience journal or on sheets made up into charts for each variable to compare.Observations should be in written form with diagrams. Examples of areasto focus on are color, texture, shape, size, weight (if students weighedthe pieces at the beginning).
-Students should also compare changes in the banana peels. Which changedthe most? Did the change the same way? Did any stay the same?
-After a few weeks, students should formulate conclusions and write thelab up.
-Direct students to throw away all the bags. Do not open them, there isbacteria.
Results:
The peel in the soil should disintegrate/decompose in a few days or fairlyrapidly. Room temperature affects this process. The peel in the air onlyshould shrivel up, become smaller and get hard and dark in color, but willnot decompose very soon. The one in the water should break up into manypieces and become soft and dark brown. The one in the light should becomedark brown and will respond to temperature fluctuations.
Lesson Four: Worm Farm
Objectives:
-Students will observe the process of decomposition in another situation.
-Students will observe what kinds of materials are decomposable (biodegradable).
Time/Grouping:
15-20 minutes, whole class to small group
Materials:
-A small glass or plastic container (at least 32 oz.), a 5 gal. Aquariumworks
-12 oz. of organic peat soil (basic garden soil)
-1 full page of shredded newspaper
-1 spray bottle with water
-5-10 red earthworms (available at bait shop)
-vegetable scraps
-small piece of foil, tissue
Procedure:
-Fill the container at the bottom with the soil.
-Shred the newspaper into thin strips.
-Add worms.
-Spray the newspaper until damp, not soaked.
-Place the shredded, damp newspaper in the container.
-Add vegetable scraps (small amount), foil and tissue.
-Assign students to take care of the farm: Spray to maintain dampness asneeded. Maintain food scraps.
-Have students observe at least once a week and record these in a sciencejournal or on charts. They should be looking for changes or if some thingsdo not change.
-Keep the farm long enough to observe the recycling of materials into soil.After the project is over, return worms to the soil.
Lesson Five: Observations and Recommendations
Objectives:
-Students will revisit the KWL and discuss and list what they learned fromvarious activities.
-Students will write for a variety of purposes, choosing from a list oftopics.
Time/Grouping
-45 minutes, whole class to individual
Materials:
-original KWL chart
-writing materials
Procedure:
-Initiate and facilitate discussion of observations and information learnedfrom various experiments, the video, or resource materials (books, magazines,newspapers) regarding the topic of what decomposition is and how it helpsus with our waste situation, how it works in a landfill. If students areaware of composting, discuss it.
-Direct students to write a paper on one of the following topics, or a topicof their choice, related to unit, per teacher approval: (must be specific)
-comparison of Banana experiment to the Worm Farm demonstration - couldbe a chart, narrative or a Venn diagram.
-compare active versus inactive decomposition - worms vs. air, water.
-recommend a plan for our school to dispose of our solid waste.
-recommend a plan for your family to dispose of solid waste.