coachriley3
Forum Newbie
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One morning you are lying in a meadow under the blue summer sky of Connecticut. You notice a small bird (likely a song sparrow but unfortunately you have forgotten your binoculars so you just assume) perched on a branch in the shade of an old oak tree. You also notice another small bird (again likely a song sparrow) standing on top of a rock under the beautiful June sun. You wonder, why they are not both in the same type of environment. One of them must be expending more energy to keep themselves in heat balance.
You know from your research on song sparrows that the body temperature of a song sparrow is usually 39ºC, their total body surface area is about 0.0036m2, the surface area of their feet is about 0.0008m2, and their emissivity is 1. Their feathers are about 0.04m thick with a thermal conductivity coefficient of 0.033 W/m ºC. Their evaporative water loss averages 0.0023g/m2sec. Average metabolic rate is 10W/m2. So you decide to measure some temperatures. The temperature of the branch the bird is sitting on is 28 ºC, the temperature of the rock the bird is standing on is 35 ºC. You figure out that the radiant energy absorbed from the tree to the bird is 0.0003W and the radiant energy absorbed from the rock to the bird is 0.0010W. Since there is no wind present, you assume there is no convection happening. In addition, the birds are in the midst of the breeding season and are not storing any extra nutrients.
Figure out which bird is expending more energy to keep themselves in heat balance.
I think I figured it out, but I am not sure if Im correct. Does anybody want to take a shot and help me out here because Im curious if I approached this question correctly.
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| new_n_lost
Politically InCorrect
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FORUM RULES-- Those who believe in telekinesis, raise my hand. I get enough exercise just by pushing my luck --P4U World.." The pure and simple truth is rarely pure and never simple."
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| unique1
InGodITrust
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Probably the bird sitting on the branch .
Are you preparing for USMLE ?
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I can't change the direction of the wind, but I can adjust my sails to always reach my destination.
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| coachriley3
Forum Newbie
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yes. I just wanted to know if i set up the numbers up correcrly because i got the rock..i want to compare mine to somebody elses
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| unique1
InGodITrust
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I can't change the direction of the wind, but I can adjust my sails to always reach my destination.
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