This exercise would work well in a lesson as an introduction to the subject of prejudice or simply the concept of similarities and differences. First give one lemon to each child. Then ask the children to "get to know your lemon." Children will examine their lemons: smell them, touch them, throw them in the air, and roll them around. After a few minutes, collect the lemons in a big basket, and ask the children to find their lemons in the pile. Remarkably, most children will recognize their lemons at once. Some will even get protective of them.
Next, ask the children to describe how they recognized their lemons. "My lemon was big," one might say. "My lemon had a mark on one side." And another, "My lemon had dents and bruises." Then talk about how people, too, come in different sizes, different shapes, different shades of color, different "dents and bruises."