* You and your friend can do it * Beach * Backyard of your house * Sunny day
Let any one of you try to get a tan by sunbathing in the backyard and the other spend time at the beach for the same purpose. Observe what you see in both of you skin and compare who got more sun tan.
The person in the beach had more sun tan because the ultraviolet rays reflect more on the sand than ordinary mud leading to increased exposure and tan at the beach.
The person in the beach had more sun tan than the person in the backyard of the house.