Sudarshan's+Labs

//**Note: The lab is posted in PDF format, and thus, the embedded animations and demonstrations do not function.**//
 * __Chapter 2 Lab____: Black Body Radiation__ - Posted on September 14, 2010**

__Daisy World Lab - Response Questions__ - October 12, 2010
1. The death rate seems to control the total number of daisies (represented by the living area) as per the following relationship: 1 – death rate = living area/# of daisies. When the living area is increased, the number of daisies on the planet is increased. We can also see from the second graph that the number of daisies and temperature of the planet are inversely related. Thus, we can conclude that as the death rate decreases, the daises have an increased ability to control (reduce) the temperature of the planet.

2. As the insulation increases, the daisies have a greater ability to control the temperature of the planet. A large part of vegetation’s ability to cool an environment is related to the plants’ release of water vapor through the transpiration process. Only if there is an atmosphere present (higher insulation) will this method work. In a spatial structure of the planet, the daisies may be able to control the temperatures at lower insulations, thereby increasing their resiliency and ability to survive in harsh conditions.

3. The initial switch from 1000 to 5 in the “max per” parameter affected the % area of the white daisies and the daisies’ ability to control the temperature over the solar luminosity interval from approximately .8 to .85. When we increase the max per parameter by increments as instructed (shown above), we can see that as the maximum value increases, the number of daisies present is equal at all habitable luminosity values. In addition, the range of solar luminosity values at which the daisies can survive also seems to increase slightly.

6. When the number of black daisies is larger than the number of white daisies, the temperature of the planet is above the barren rock temperature. When the opposite is true, the temperatures fall below the barren rock temperature. The temperature equals that of the barren rock temperature when the number of black daisies equals the number of white daises, or when there are no daisies on the planet. The above inference only has predictive power in daisy worlds with three colors. When more colors are introduced, it seems that these additional colors also influence the temperature.

7. As solar luminosity increases, it seems that a desert environment fosters a higher increase in the temperature than a barren rock environment. When the desert albedo parameter was inserted, the temperature soared to 80 degrees Celsius at a solar luminosity of 1.5, whereas the temperature in the barren rock environment only reached this high at a luminosity of 1.9. Moreover, when inserting the given short vegetation albedo values for daisies, one can see that plants on earth are not nearly as resilient as the daises in the model, as the range of survival decreased by six units of solar luminosity.

9. When looking at the 12-color scenario, one can clearly see an evolutionary pathway. As solar luminosity increases over time, a higher albedo is needed for the daisies to survive. Thus, at lower luminosities, we see daises with low albedos (around .5). As time progresses, the luminosity increases, leaving natural selection to favor species that have evolved to have higher albedos than their ancestors. This explains the active progression of colors and increasing vales of albedo over time (max at .75), until the luminosity becomes too much for the daisy species to tolerate.

10. Obviously, objects with higher albedo values tend to be lighter and more reflective. But the color progression of the daisies over time does not follow this trend, as we see dark colors in between lighter ones, etc. Thus, the appearance of the different daisies is purely random, and not based on evolutionary succession. In order to select a correct explanation from the ones given above, we have to analyze the evidence supporting each one. Whichever theory has more support for its cause and fewer arguments against it will be the winner.

11. The answer once again has to do with adaptation to the environment and evolution. Initially, many different types, or species, of daisies grow in the environment. Overtime, some of these species are more successful than others, and the process of natural selection eventually weeds out the less successful species.

12. Even those who write “just so” stories can come up with elaborate and convincing arguments towards their cause. However, I believe that we as researchers must look to see whether the source provides physical evidence in the form of data. In other words, has the source physically performed an experiment or research and analysis regarding the topic that supports their claim? Alternatively, are they simply piling together arguments based on existing information and their imagination? By reading and researching proactively, researchers can effectively discern fluff from real information.