| Lab Name |
Using sensors to determine which wavelengths of light are used for photosynthesis.
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| Subject Area |
Biology, Math
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| Grade |
9
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| Topic |
Scientific inquiry - photosynthesis experiment
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| Experiment Title |
Using sensors to determine which wavelengths of light are used for photosynthesis.
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| Hardware |
COSMOS Toolkit, IoT Nodes with sensors (i.e., temperature, humidity, polluting dust, luminocity, CO2)
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| Software |
COSMOS Toolkit Framework, Chronograf.
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| Number of Sessions to teach the topic |
1-3 sessions (2-3 weeks project)
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| Educational standards to be addressed |
NYS Core Curriculum
- Key Idea 2
Beyond the use of reasoning and consensus, scientific inquiry involves the testing of proposed explanations involving the use of conventional techniques and procedures and usually requiring considerable ingenuity.
- Key Idea 3
The observations made while testing proposed explanations, when analyzed using conventional and invented methods, provide new insights into natural phenomena.
- Key Idea 5
Organisms maintain a dynamic equilibrium that sustains life.
NGSS
- HS-LS1-2
Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.
- HS-LS1-5
Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy.
- HS-LS2-3
Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in ecosystems.
- HS-LS2-5
Develop a model to illustrate the role of various processes in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.
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| COSMOS concepts to be used for the lab |
Real-time data, Chronograph formatting of results allow students to quantify relationships between correlate light, leaf size and photosynthetic activity.
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| K12 Educational Goals (How the educational goals are achieved through teaching using the experiment, how the topic is connected to the COSMOS concepts used) |
It develops a number of research-related skills (i.e. assess data and problem solve experiments), as well as understand how organisms are capable of adapting to their environment.
They will develop a number of research-related skills (i.e., assessing Chronograf results and problem-solving experiments).
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| Short Description and Walk-through of the experiment |
- Days 1-4 Student teams grow Brassica rapa plants in a potting container under optimal conditions (http://www.fastplants.org/pdf/growing_instructions.pdf; https://fastplants.org/2017/09/19/physical-environment-blog/)
- Day 5 Student teams spend 10 minutes, using sensors to measure carbon dioxide (CO2) levels just outside of the classroom in the hallway, no plants should be present. They can measure and record this value using several locations in the hallway and calculate the overall average (CO2 levels are approximately 405 parts per million or 0.1% of the atmosphere).
- Set-ups: Two student teams are assigned the same colored wavelength of light. For instance, one team will be given red-colored cellulose sheet to place over the fluorescent light bulb; which will be close (5 cm) or far away from the plant (100cm); different distances of the light source should result in different influence on a plant’s photosynthetic capability (CO2 absorption). Other teams will test blue light, white light and green light (negative control).
- Measurements: Confirm intended wavelength with the sensor, in the case of red cellulose paper filtering the fluorescent light, the sensor should indicate absorption at 630-750 nm.
Measure intensity of red light (or blue, white, green wavelengths) absorbed by the sensor should vary significantly at 5 or 100 cm distance from the plant.
*Don’t forget to keep watering plants over the next 5 days; these young plants want to grow.
- Day 10 Student teams measure whether the plant is performing photosynthesis (measured by CO2 absorption).
Student teams repeat the background CO2 level measurements in the hallway (outside of the classroom) that they performed on day 4.
Students return to the classroom and place the sensor near their light-exposed plant. A large, transparent beaker or bag should be placed over the potted plants and sensor. Students record an average CO2 value for 5 minutes.
Next students measure CO2 absorption per cm2 of plant leaves. (Trace outline of all leaves and calculate area within each (graph grid area = 1 cm2); subtract average CO2 in hallway from CO2 near plant to get CO2 absorption; divide CO2 absorption by total plant leaf surface area).
Students should be able to measure overall size of the plant, noticing a significant difference between plants exposed to different wavelengths, at varying distances (white light at 5 cm from plant should have the greatest positive effect whereas green light should have the least impact).
Student teams upload their data onto a designated Google drive spreadsheet “1st Experiment.”
Students generate a line graph demonstrating the relationship between light’s wavelengths, distance to the plants leaves and the plant’s photosynthetic capability and size.
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| Testbed mapping of the experiment |
Testbed nodes-sensors can provide real-time data on temperature, humidity, and CO2 and help manage certain fragile or threatened ecosystems.
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