Description:

Students examine the ecosystem of Lake Wilmar through three coordinated performance tasks. In the first task, Decline in Freshwater Animal Populations, students use pH paper and water samples to investigate the effects of pH on freshwater animals. For the second task, Hot Rocks and Water, students use limestone samples and hot water baths to investigate the concepts of heat and temperature. In the last task, Rock Erosion, students investigate the effects of polluted vs. non-polluted water on rocks.

The task assesses students' abilities to make simple observations, interpret and produce graphical data, use simple tools, determine and design additional experiments, apply their understanding and observations to form explanations and predictions.

This tasks together are designed to take students approximately 90 minutes to complete.

Overall Task Content Area:

Physical, Life, and Earth Sciences

Specific Knowledge Areas:

Ecosystems, Heat and Temperature, Erosive Processes

Performance Expectations:

• conducting investigations
• using equipment
• gathering, organizing, and representing data
• formulating conclusions from investigational data
• applying scientific principles to develop explanations and solve new problems

12 A SI 1: Abilities necessary to do scientific inquiry: Grades 9-12
1.4 Formulate and revise scientific explanations and models using logic and evidence. Student inquiries should culminate in formulating an explanation or model. Models should be physical, conceptual, and mathematical. In the process of answering the questions, the students should engage in discussions and arguments that result in the revision of their explanations. These discussions should be based on scientific knowledge, the use of logic, and evidence from their investigation.

8 C LS 4: Populations and ecosystems: Grades 5-8
4.4 The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition. Given adequate biotic and abiotic resources and no disease or predators, populations (including humans) increase at rapid rates. Lack of resources and other factors, such as predation and climate, limit the growth of populations in specific niches in the ecosystem.

8 D ESS 1: Structure of the earth system
1.10 Global patterns of atmospheric movement influence local weather. Oceans have a major effect on climate, because water in the oceans holds a large amount of heat.

8 B PS 3: Transfer of energy: Grades 5-8
3.2 Heat moves in predictable ways, flowing from warmer objects to cooler ones, until both reach the same temperature.

(Use the "hot" link on the PALS home page to check the full text of related National Science Education Standards, if desired.)

National Council of Teachers of Mathematics:

PS2: Solve problems that arise in mathematics and other contexts:
Grades 9-12

General Instructions to the Teacher:

This task is designed to take students approximately 90 minutes to complete.

Students will be working individually during this exercise.

Students should be ready to work as soon as the period begins. The materials should be set out at each lab station, if possible. A central supply area, if needed, should be easily accessible. All supplies should be clearly labeled.

Materials for Classification:

The teacher will need:

• dilute acid
• plastic cups
• Styrofoam cups
• labels
• water
• hot plate
• thermometers
• balance
• Large container for water bath
• graduated cylinders
• small pieces of limestone
• string
• pH paper
• pH value strips

General area:
• rock samples
• balance
• hot plate
• container with water for hot water bath
• string

Decline in Freshwater Animal Populations:
• labeled water samples for Taylor Creek, Lake Wilmar, and Spillway Wastewater
• three strips of pH paper
• pH value strip

Hot Rocks:
• limestone sample
• string
• 50 ml graduated cylinder
• two Styrofoam cups
• thermometer

Rock Erosion:
• two labeled plastic cups for wastewater and fresh water
• two labeled plastic cups containing wastewater and fresh water
• limestone sample

Preparation for one station of "Decline in Freshwater Animal Populations":
• Using a dilute acid, prepare three water samples which will demonstrate varying acidity when tested with pH paper
• Label the most acidic solution "Spillway Wastewater"
• Label the slightly acidic solution "Lake Wilmar Water"
• Label the neutral solution "Taylor Creek Water"
• Prepare a placemat titled: "Decline in Freshwater Animal Populations"
• Label areas for each of the water samples with a circle in which to place the cup with the sample name in the circle.
• Label an area for pH paper and value strip, and place three pieces of pH paper and the value strip there.

Preparation for one station of "Hot Rocks":
• Prepare a placemat titled: "Hot Rocks."
• Label an area for string and cut a 6-8 inch piece of string to place there.
• Label an area for the thermometer.
• Label an area for the graduated cylinder.
• Label Styrofoam cups "Part A - (water/rock)" and "Part B - (water/water)".
• Place the cups in labeled areas.
• Prepare hot water bath for student use.

Preparation for one station of "Rock Erosion":
• Prepare a placemat titled: "Rock Erosion."
• Label an area for cups containing water samples.
• Label an area for the cups for experiment.
• Label these cups "Cup for Freshwater" and "Cup for Wastewater."
• Label an area for the limestone.
• Prepare an acidic solution for the wastewater sample and label the cup with the sample "Spillway Wastewater."
• Prepare a neutral solution for the fresh water sample and label the cup with the sample "Fresh Water."
  

Safety:

• Caution students that the hot plate and water bath are hot!
• Instruct students not to taste or drink water samples.
• Be careful.
• Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks.

Extensions/modifications:

• This is an extended, coordinated three part performance task which must be taken in order.

Set up for Decline in Freshwater Animal Populations

Set up for Hot Rocks

Set up for Rock Erosion