Probeware Lesson Plan
Heather Booher
Erin Campbell
Lisa Franks
EDCI 5724
Lesson Plan: Can a Goldfish Live in your Bathtub?
Purpose/rationale: The purpose of this lesson is for students to investigate water quality following the 5-E learning model. By measuring dissolved oxygen levels in various water samples, students will explore the relationship between water quality and factors necessary to support life in an ecosystem.
SOLs:
LS-1: The student will plan and conduct investigations in which
j) and understanding of the nature of science is developed and reinforced.
LS-4: The student will investigate and understand that the basic needs of organisms must be met in order to carry out life processes. Key concepts include:
b) animal needs (food, water, gases, shelter, space)
LS-10: The student will investigate and understand how organisms adapt to biotic and abiotic factors in an ecosystem. Key concepts include:
b) characteristics of land, marine and freshwater ecosystems
LS-12: The student will investigate and understand the relationships between ecosystem dynamics and human activity. Key concepts include:
e) environmental issues ( water supply, air quality, energy production, and waste management)
Materials and Resources
Activity sheet 2 Elodea plants
Laptop computer
Dissolved Oxygen Probe
2 Gold Fish
Four small bowls
Tap Water
Pond Water
Creek Water
Engage:
The teacher will engage the students in learning about water quality by demonstrating the difference in dissolved oxygen levels between water in a gold fish bowl and water alone. The teacher will prompt the students to think about what factors might influence dissolved oxygen in a sample of water. The teacher will invite the students to participate in making predictions and comparisons with the different water samples provided. These water samples include one bowl with distilled water only, one with a goldfish only, one with an Elodea plant only, and the final being one with a goldfish and an Elodea plant. (30 min.)
Explore:
Students will first practice using the dissolved oxygen probe by testing water samples from their home or a nearby pond. Students will explore the amount of dissolved oxygen in the four water samples provided using a dissolved oxygen probe connected to a laptop computer. (20 min.)
Explain:
Each group will interpret their data by comparing results with other students in the class. Students will use a variety of literary sources to supplement their ideas about the importance of dissolved oxygen as a measure of water quality and the types of life that are influenced by oxygen in water. (10 min)
Elaborate:
Students will extend their understanding of how dissolved oxygen varies in different water samples. They will be invited to think about what other factors influence the amount of oxygen in the water and how it might vary with different ecosystems. (10 min)
Evaluate:
Students will provide the following as evidence for understanding dissolved oxygen concentration.
Performance Criteria |
Evidence |
*Points Assigned |
Students come prepared to participate in lab |
Bring water sample from home or pond. |
|
Students explain and demonstrate the importance of a dissolved oxygen measurement in assessing water quality and the health of an ecosystem. |
Answers appropriately on activity sheet and their dissolved oxygen reading is included on the class scatter-plot graph. |
|
Students elaborate on dissolved oxygen lesson by identifying factors that might influence water quality in different ecosystems. Students elaborate on other measures of water quality. |
Researches question using resource books, and completes activity sheet. |
|
Students discuss the relationship between water quality and the health of an ecosystem. |
Students understand the effects of dissolved oxygen on freshwater ecosystems. |
|
*5= participates and completes activity sheet without errors
4= participates and completes activity with few errors
3= does not bring in water sample, completes activity sheet
2= very little participation, incomplete activity sheet
1= minimal participation, misses whole sections, such as elaboration
section, on activity sheet
0= no participation in lab at all
Heather Booher, Erin Campbell, Lisa Franks
Dissolved Oxygen Activity Sheet
Purpose: In this activity, you will investigate water quality by measuring dissolved oxygen levels in various samples of water.
Engage
Which fish bowl do you think will contain more dissolved oxygen, the empty bowl, or the one containing the goldfish? Or will there be no difference?
Was your prediction correct?
What role does dissolved oxygen play in an aquatic ecosystem? How does the oxygen get into the water?
What effects (positive or negative) would human interactions and pollution have on water quality and dissolved oxygen levels?
Explore
Which water sample 1) water alone, 2) goldfish, 3) Elodea, or 4) goldfish + Elodea do you think would have the most dissolved oxygen? The least dissolved oxygen? Why?
Using the dissolved oxygen probe attached to the computer, measure the DO level of the four water samples.
Was your prediction correct?
Explain
Why do you think dissolved oxygen is an important measure of water quality?
Can you think of a possible reason why there is a difference in the amount of dissolved oxygen in each water sample?
Elaborate
Using the different resource books, identify two ecosystems that would naturally differ in dissolved oxygen levels.
How could water quality affect these ecosystems?
What types of fish or organisms might survive in lower quality water?
Info for teachers:
When filling bottles/jars with water samples, it is important to not trap any air in the bottle and to avoid introducing any turbulence, since turbulence will mix air into the samples and increase the dissolved oxygen levels. There are several different ways to fill the bottles: 1) submerge the bottle in the sample, let it fill, then cap it while it is still submerged; 2) pour the sample very gently from a beaker, creating as little turbulence as possible;
A quick review of DO and water quality : Oxygen is critical for the life processes of nearly all organisms. In the aquatic environment, oxygen must be in solution in a free state before it is available for use by organisms. The dissolved oxygen (DO) concentration in a body of water is often used as a benchmark indicator of water quality. Desirable fish species such as trout and perch require a minimum of 8 ppm dissolved oxygen to survive. Less desirable fish such as carp and catfish can survive at dissolved oxygen levels as low as 2 ppm. Below 2 ppm only invertebrates such as sludge worms and mosquito larvae can survive.
Oxygen enters water via diffusion from the air and photosynthesis by aquatic plants. Physical factors such as the temperature and salinity of the water and the partial pressure of oxygen in the air influence the rate at which oxygen enters the water. In the absence of mixing by winds, currents, tides or other flows, the only way that oxygen is distributed through water is by diffusion.
Biological processes such as photosynthesis and respiration can also significantly affect dissolved oxygen concentrations. Photosynthesis usually increases the oxygen concentration in water. Respiration requires oxygen and will usually decrease dissolved oxygen concentration. Respiration by microorganisms can be particularly influential in bodies of water, because populations of microbes can increase quickly. Warm temperatures usually accelerate microbial growth, increasing the demand on dissolved oxygen.
Water Pollution and Dissolved Oxygen
Water pollution decreases dissolved oxygen concentration, usually by stimulating microbial growth and thereby increasing the demand for oxygen for microbial respiration. Decomposition of dead organisms is also carried out by microbes through oxygen-requiring processes. Any pollution event that kills large numbers of organisms (such as spills of herbicides or pesticides) results in an increase of decomposers and the use of oxygen for decomposition. Although the effect is not direct, fertilizer pollution can diminish dissolved oxygen in the same way. The pollution first stimulates over-proliferation of aquatic plants, which may first produce additional oxygen, but eventually the plants will die and decompose.
References: http://mindflight.plymouth.edu/icet/2003/profile/profileapbio/labs.html