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Daisyworld - This World is Black and White
http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10898

NASA, Sphere feature LOOP

This short, engaging video created by NASA presents a complex topic via a simple analogy. The idea of positive and negative feedback is demonstrated by Daisyworld - a world with black and white flowers growing on it.




Learn more about Teaching Climate Literacy and Energy Awareness»

ngssSee how this Video supports the Next Generation Science Standards»
Middle School: 2 Disciplinary Core Ideas
High School: 5 Disciplinary Core Ideas

Notes From Our Reviewers The CLEAN collection is hand-picked and rigorously reviewed for scientific accuracy and classroom effectiveness. Read what our review team had to say about this resource below or learn more about how CLEAN reviews teaching materials
Teaching Tips | Science | Pedagogy | Technical Details

Teaching Tips

  • Consider using the terms self-reinforcing cycle instead of positive feedback, and self-muting feedback instead of negative feedback. Emphasize to students that these terms are related to mathematical processes, not emotional ones.
  • A lot of information is presented quickly. Educators may want to play it once all the way through, then again to stop/start and explain things.
  • This resource will enhance any lesson that is about the relationship between changes in biotic and abiotic variables.
  • Consider asking students to draw a causal loop diagram for each of the loops and see how they join together.

About the Science

  • The video illustrates the concept of albedo. Black daisies absorb solar radiation while white daisies reflect it. A change in atmospheric temperature drives a change in daisy population, which then drives a change in atmospheric temperature, and so on.
  • The concept of albedo is accurately described as the percentage of solar radiation that bounces off the surface (mirror = 100% reflected energy).
  • Comments from expert scientist: This is a very nice, short video explaining the concepts of albedo and feedbacks using Daisy World as an example. The video is accurate, easy to understand and well produced. It does a nice job of explaining how the Daisy World model relates to the real world.

About the Pedagogy

  • This video is a good adjunct to use in a lesson on feedbacks loops in environmental and climate systems. As this is a complex topic, it will need additional explanation by the teacher.
  • A potentially confusing element is the counter-intuitive nomenclature of positive vs negative feedbacks. Educators will need to review these concepts with students.

Technical Details/Ease of Use

  • Good quality and easy to use. Transcript available.

Next Generation Science Standards See how this Video supports:

Middle School

Disciplinary Core Ideas: 2

MS-ESS2.D1:Weather and climate are influenced by interactions involving sunlight, the ocean, the atmosphere, ice, landforms, and living things. These interactions vary with latitude, altitude, and local and regional geography, all of which can affect oceanic and atmospheric flow patterns.

MS-PS4.B1:When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object’s material and the frequency (color) of the light.

High School

Disciplinary Core Ideas: 5

HS-ESS2.A1:Earth’s systems, being dynamic and interacting, cause feedback effects that can increase or decrease the original changes.

HS-ESS2.C1:The abundance of liquid water on Earth’s surface and its unique combination of physical and chemical properties are central to the planet’s dynamics. These properties include water’s exceptional capacity to absorb, store, and release large amounts of energy, transmit sunlight, expand upon freezing, dissolve and transport materials, and lower the viscosities and melting points of rocks.

HS-ESS2.D1:The foundation for Earth’s global climate systems is the electromagnetic radiation from the sun, as well as its reflection, absorption, storage, and redistribution among the atmosphere, ocean, and land systems, and this energy’s re-radiation into space.

HS-ESS2.E1:The many dynamic and delicate feedbacks between the biosphere and other Earth systems cause a continual co-evolution of Earth’s surface and the life that exists on it.

HS-PS4.B2:When light or longer wavelength electromagnetic radiation is absorbed in matter, it is generally converted into thermal energy (heat). Shorter wavelength electromagnetic radiation (ultraviolet, X-rays, gamma rays) can ionize atoms and cause damage to living cells


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