Reprinted from Connect
Vol.22 No.4, March/April , 2009
Focus on: Science: More than a Method
Grade Level: 6-8
Grade Level: K-2
Grade Level: K-8
Grade Level: 3-5

Ecosystems

A Hands-On Science Unit

by Sylvia Dixon

Because of the increase in high stakes testing and accountability as a result of No Child Left Behind, instructional focus in many cases is directed toward math, reading, and language arts. As a result, science and social studies are often viewed as unimportant at the elementary level, more like enrichment subjects rather than opportunities to foster higher-level thinking. Despite the lack of emphasis and limited resources available in low socioeconomic areas, it is crucial that teachers provide in-depth and hands-on science instruction.

Starting with a great kit

Ecosystems (NSRC Science & Technology for Children, 2002) is a unit that provides a variety of teaching and assessment methods, cooperative, hands-on learning, that enables our students to make their own discoveries—all of which meet the individual learning styles of our students. The Ecosystems unit is designed to provide all students with stimulating experiences in the physical, earth, and life sciences and technology, while simultaneously developing their critical thinking and problem solving skills. I incorporate this unit into my fourth-grade curriculum every year with great success.

My self-contained classroom includes emotionally and mentally disabled students, special education students, gifted students, and regular education students. I have taught this unit when my students' abilities ranged from second grade to sixth grade. Our district is located in a low socio-economic area where 83% of the students in our school qualify for a free or reduced-cost meal program.

Aquariums and terrariums

We begin by collecting 2-liter plastic soda bottles to serve as our aquariums and terrariums. The kit guide instructs students to create a terrarium, then an aquarium, and to connect them after the separate environments have stabilized. One connected set is used for observing creatures; the other for observing the effects of pollutants. The aquarium consists of gravel, water, elodea, duckweed, and algae. Into one aquarium, students add pond snails and mosquito fish (many local aquatic merchants will donate the mosquito fish).

The terrarium consists of soil, alfalfa seed, mustard seed, grass seed, and leaf litter. After a week to ten days, the seeds will sprout. When the seeds in the terrariums begin to grow, the students add crickets and isopods to one of the terrariums.

Introducing a pollutant

Next the students are directed to insert pollutants that represent acid rain (vinegar), agricultural runoff (plant fertilizer), and road salt (kosher salt) into the experimental ecosystem (the one that contains no animals). They observe and record how the pollutants affect the ecosystem.

Oil spill!

As an extension of the pollutant experiment, I challenge my students to invent the most effective method for cleaning up an oil spill. Each student participates in a designated role within a cooperative group. The four roles are worker, timer, recorder, and scientist. After the worker collects the group's materials, they test and record the effectiveness of each material. Based on the observations during the experiment, each group modifies one material or combines materials to see if the oil can be removed more efficiently.

Each group will present their question, hypothesis, procedure, and the materials they utilized, including the results of their experiment. Some examples of the materials they use are: cotton balls, straws, sand, sponge, feathers, and detergent. Students also decide the best method to use to dispose of the materials they used to clean up their oil spill. There are many ways of cleaning the shore and organisms. Of the various methods used during the experiment, the students must conclude which material conserves the most water.

The Science Hour

The enthusiasm of my students inspired me to organize a Science Hour at our school. In the Science Hour, each cooperative group visited different classrooms in the school to share what they had learned. They demonstrated their experiments and discussed their findings with other students.

The Science Hour pushed my class beyond their own learning by demanding that they become demonstrative teachers. This project not only helped the students in my classroom, but it exposed all the students in our school as a community to our stimulating and innovative learning experience.

By constructing and carefully observing a model ecosystem, students were able to explore interrelated organisms that link to their natural environment. This project gave students the opportunity to build a deeper understanding of important scientific concepts. As they made their own discoveries, students developed positive attitudes toward science through hands-on investigations of their ecosystems. My students furthered their science investigation skills while also honing their skills in mathematics, language arts, and social studies. Using the kit as a starting point, we conducted the study in a way in which each learner could actively construct knowledge.

©2009 Synergy Learning Inc. All rights reserved.

Jennet, P. Ecology. Creative Teaching Press, Inc.: Cypress, CA, 1995.

National Science Resources Center. Science and Technology for Children: Ecosystems. Smithsonian Institution: Washington, DC, 2002. Explicit details of this unit (with exclusion of the oil spill experiment) and purchasing information can be found at Carolina Biological Supply Company, http://www.carolina.com.

NOTE TO TEACHERS:
Many states require permits to import live materials and have strict guidelines for disposing of organisms at the conclusion of a unit. Check with your state Fish and Wildlife Department. Never release non-native organisms into the wild.

Sylvia Dixon - Sylvia has taught fourth and fifth grade and is currently teaching Gifted Education for grades two through eight. She is a graduate student at the University of Southern Mississippi working toward a Specialist Degree in Education Administration. (2009)
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