Tuesday, May 31, 2016

Guest Post: Heat absorption by colors (4th Grade Science Fair)

My name is London Gopalakrishnan. I’m a 4th grader at Montclair Elementary in Oakland and I’m 9 years old. This is my first ever blog post. Hope you like it.

For this year’s science fair project, I decided to do an experiment that tested which colors absorb the most heat. I thought it would be interesting because solar energy is the future of helping our planet use smarter natural resources. I didn’t have access to silicon, which solar panels are made of, so I used other materials: glass, paper and water.

I collected my data by getting the materials and putting it under sunlight. Every 10 minutes, I noted the temperatures for an hour. And then, I used software that my dad works on to make sense of it.

My Hypothesis: If the darker colors have hotter temperatures when put into the sunlight, then that means the darker colors absorb more heat.


Conclusion: In conclusion, dark colors absorb more radiated heat from the sunlight while lighter colors reflect it. Black paper, black water and black glass all heated up the most after one hour in the sun (and had the highest temperatures for all materials tested).

For paper, overall black had the highest average temperature of 95 degrees, followed by green at 92, red at 91, blue at 88 and white at 85 degrees. All colors absorbed the most amount of heat within the first 10 minutes. The clouds blew in after 30 minutes and blocked the sun’s rays, and that may be the reason why the temperature dropped. There was a 10 degrees difference between black paper (hottest) and white paper (coolest).
For water, overall black turned out to be the warmest at 77.5 degrees on average, followed by blue at 76, green at 75.5, red at 74.5, and clear at 72.5 degrees. The temperatures of the water samples were not affected by the cold wind and clouds. (Sunrays still shine through clouds!) There was a five degrees difference between black water (hottest) and clear water (coolest).
For glass, overall black absorbed the most heat at 81.5 degrees on average, followed by blue at 81, clear at 77.5 and purple at 76.5 degrees. There was a five degrees difference between black glass (hottest) and purple glass (coolest). The purple glass we tested was the smallest and shallowest with a wide opening, which may have let heat out more than the other glass bottles that were deeper.
This shows that different colors reflect and absorb the sun’s energy differently. And, different colored materials also absorb the sun’s heat differently. Overall, the darker colors absorb more heat.