Color & Light

Most recent answer: 10/22/2007

Q:
I used food coloring in ice to test what color would melt the fastest. My findings were 2 of the 3 times Yellow melted faster than the other 3 primary colors. Do you have some kind of facts to support why the lightest color woudl melt fastest instead of the darker color?
- Liah
Florida
A:
The lighter the color the more light reflected and hence the darker the color the more light absorbed. Therefore if melting different colors of ice theoretically the darker colors should melt faster as they are absorbing more light. This is also why we wear lighter colors in the summer to stay cool. The light is reflected off of our clothing.

It is possible that the color you see as light may actually be absorbing more of the light than the one you see as dark, since there’s some subjective estimation involved. However, it’s hard to do experiments like this in a carefully controlled way, to make sure the differences aren’t just form accidental differences in the size of the ice cubes or the patterns of warm airflow, etc. Just to see if there’s any effect at all, you might want to compare ice with no dye to ice with a mixture of all three primary pigments. If the absorbed light is important, the dark cubes should melt sooner than the clear ones.

(published on 10/22/2007)