Aquatic Ecosystem for Middle School

Transcription

1 Aquatic Ecosystem for Middle School Teacher Edition By: Melissa Wirth and Susan Cline *This lesson assumes that students understand dissolved oxygen is a requirement of aquatic life. NGSS Alignment: MS-LS2-4 Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations. DCI- LS2.C Ecosystem dynamics functioning and resilience Ecosystems are dynamic in nature; the characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all of its populations. Crosscutting Concepts Stability and Change Small changes in one part of a system might cause large changes in another part. Science and Engineering Practices Develop and Using Models Develop a model to describe phenomena. Analyzing and Interpreting Data Analyze and Interpret data to provide evidence for phenomena. Common Core State Standard: RST Cite specific textual evidence to support analysis of science and technical texts. 1

2 WHST Write informative and explanatory to examine a topic and convey ideas. Objectives: Upon completion of this lesson students will be able to: 1. Construct an argument based on evidence about the physical and biological components that affect an aquatic ecosystem. Materials: Explore I Lemon juice Milk Vinegar Distilled water Milk of magnesia Baking soda Antacid tablets Tomato juice Dark soda Aged pennies Rusted bolts Pieces of concrete Painted surfaces Pieces of wood Cotton material Science journal Connecting I Science journal Explore II Materials from Explore I Liquid drain cleaner Litmus paper Chart paper Science journals ph scale Connecting II Science journals 2

3 Explore III Petri dish Agar Moldy bread Filter paper discs Alkaline solution Acidic solution Connecting III Science journals Explore I How do these substances affect these particular materials? 1. Provide students with various substances that represent levels along the ph scale with which to observe acidic and basic effects against certain materials. Examples of these substances could be lemon juice, milk, vinegar, distilled water, milk of magnesia, baking soda, antacid tablets, tomato juice, dark soda. 2. Materials that are to be subjected to the substances could include aged pennies, rusted bolts, pieces of concrete, painted surface, pieces of wood, cotton material, etc. 3. Students will work with partners to observe the effects that the substances have on each of the materials. They should create a table in their science journal and log the observations as they occur. Connecting I 1. Groups share their findings with another group using science journals for comparisons. 2. What were your observations? 3. Was there a substance that reacted similarly to another substance? 4. Were there any substances that reacted totally opposite of these substances? 5. What reaction did you observe with the water? 3

4 6. Try to arrange these substances in order from most erosive to least erosive? What is ph and how do you measure it? Explore II Teacher Demonstration: Use a substance such as a common household drain cleaner on same materials students used in Explore I activity to demonstrate how extreme bases react similarly as extreme acids on substances. Teacher will introduce the term and scale called ph using litmus paper and the drain cleaner in the demonstration using caution to avoid contact with students. 1. Using the same substances in Explore I activity, instruct students to measure the ph for each substance and log the data table they create in their science journal. 2. Using the data from the table, organize the ph information from smallest to largest numbers (left to right) on chart paper and draw a picture of the substance above the ph number creating a ph scale. Connecting II 1. Have two groups share data table and ph scale drawing and discuss similarities and differences. 1. How are your charts the same? 2. How are your charts different? 3. What substance did you find in the middle of the chart most often? Why do you think that is? 4. Teacher displays a ph chart and instructs students to work with partner to identify similarities and differences between their chart and the teacher s ph scale. Circle any differences on your chart. 4

5 5. Discuss with students any differences they found between their chart and the ph scale. How do ph levels affect living things? Explore III Students will work in small groups. Each group will receive a petri dish coated with agar and a piece of moldy bread (fungus) in the petri dish. Groups will also receive a filter paper disc soaked in either an alkaline solution or acidic solution at the discretion of the teacher, which will be placed upon the mold. Students will observe the effects of their solution on the moldy bread and record results in their science journals. Connecting III 1. Students will partner up with another group to discuss and diagram results/observations. 2. Were there any similarities between groups? Create list of similarities. 3. Were there any differences between groups? Create list of differences. 4. What conclusions do you have about the relationship between your solution and the moldy bread? 5. What conclusions do you have about the relationship between ph levels and living things? 5

6 How does water quality affect living organisms? Apply Students will work in small groups to perform water analysis. Your family decided to construct a garden pond in the backyard for their newly purchased fish collection. Unfortunately, after several months, your family began to notice the fish were dying. Design an investigation using the scientific method to explain why all the fish died in the garden pond. Create a terrarium using instructions from any source you find applicable. 1. Create two identical terrariums and place soil at an angle so that when water is misted into terrarium the water will flow downhill into a pond at the bottom. 2. Place rocks under soil, and a variety of plants, and a container that will replicate a pond in each terrarium. 3. Measure ph levels at the beginning of the creation and enter on log sheet. 4. When misting, use chemicals in only one terrarium (variable) as one terrarium will be the control. 5. Use chemicals that would have been used at your home near the pond only dilute the chemicals because this will be a smaller scale example. The teacher will be responsible for mixing the chemicals. Log the names of chemicals and proportions used. Log the amounts misted, ph levels measured, and the schedule of the mistings; as well as the 6

7 observations of both terrariums. 6. Have students write up the scientific method form before they begin their experiment. Make sure they start with the hypothesis, and writing out the procedures for the lab BEFORE they begin creating the terrariums. 7. Students will work in groups and can volunteer to bring in some or all of the materials for their lab; however, the teacher will be responsible for the chemicals for the lab and will do all the mixing. Make sure students wear goggles and gloves when misting the chemicals for the variable terrarium. Expand 1. If the ph was not responsible for killing the fish, what are some other possible factors that may have contributed to the death of the fish? 2. What are some ways to correct ph? 3. How does temperature affect living organisms? 4. How do phosphates affect living organisms? 7