Why do different color of the same materal differ temperature in the same sunlight?

Question

I have a blue, red, and green cup and put a thermometer in each. Of the 3 the blue cup had the coldest temperature inside, then green, then red. I understand there may be differences in the composition of the cups but does color reflect the sun differently? I thought blue being closer to black would be hotter, but it is not?

Answer 1

The blue photon is not being absorbed from the white sun. Compared to red and green photon the blue photon has more energy. That is why most tarps are colored blue to reflect that spectrum and reduce heat. Also there are more blue photons emitted by the sun than the other colors.