In a flame test for calcium, the flame appears brick-red when viewed through a blue-glass. When an element is heated, it absorbs energy and its electrons become excited and jump to higher energy levels. When these electrons come back to their original energy level, they emit the absorbed energy in the form of light. This emitted light produces a characteristic flame color for each element. In the case of calcium, when it is heated, it emits a brick-red color flame, which can be viewed through a blue-glass to reduce the interference of other colors in the flame.