Question

You have a 20 gram piece of aluminum and a 40 gram piece of aluminum sitting in the sun. Which piece of aluminum will increase by ten degrees first? What is your evidence and reasoning?

Answer 1

Since the 2 pieces are made of the same material (aluminum), they have the same specific heat.  Then the piece of lower mass will warm up faster.

ΔT = Q/(mc)

They both receive the same heat transfer Q from the sun,  they both have the same specific heat c, so the one of lower mass m attains the higher temperature rise ΔT over the same time interval.