Absorption of Radiant Energy by Different Colors

[deleted-504420]

For science class we have to make a project as if we were going to enter it into a science fair, and I have some questions on your project for 9th graders of "Absorption of Radiant Energy by Different Colors"(I attached the link I'm using for my experiment at the bottom of this message.) In the procedure section of this project, it says to let the paper sit for "several minutes" and I'm wondering, specifically how long is “several minutes”? Also, is there a control group? If so how would you test it? Or is it just the piece of white paper? Thirdly, do you ever use equation 1, or is it there as a reference? And finally, please explain equation 2. I am confused on what all of the variables stand for. I would greatly appreciate it if you could get back to me as soon as possible, thanks!

https://www.sciencebuddies.org/science- ... ion-colors

[norman40]

Hi jaciehayes,

Your colored paper samples should be in sunlight long enough for the temperature to stabilize. You might want to check the temperature every two minutes. When the temperature stops changing, you can start your experimental measurements.

There is no control group in this experiment. But the white paper square is a kind of reference point. It's temperature is assumed to be the same as that of the surroundings for the power calculations.

Equations 1 and 2 are the same except that the temperature term (T) is expanded to show a change in equation 2. All of the terms in equation 2 are defined just below the equation in the procedure section. “P” is the power radiating from your paper squares in units of watts. “A” is the area of your paper square in meters squared. “T” is the kelvin temperature of your paper square. And “Ts” is the kelvin temperature of your white paper square. The last term “sigma” is a constant as shown in the procedure.

I hope this helps. Please post again if you have more questions.

A. Norman