How does he do it?
Answer: I was thinking there are several ways to do it, the red pills would indeed become more heated in the sun because they are at the beginning of the spectrum while blue pills are at the other end.
I did not think of cutting them in half, my solution was to dump all the pills in a single jug of water until they dissolve, stir it, and pour half the water out, then drink the rest.
Then there is the buoyancy method, depending on the type of pills one kind may sink slower than another. Cutting them did not even cross my mind and I feel dumb.