Jennifer Deits, age 10, of San Diego, Calif., for her question:
How do we get sun tan?
All of us have a dark pigment called melanin in the skin, though dark people have more of it than fair people. This dye is made in the lower layer of the skin, where it usually remains. But brilliant sunshine and dancing sunbeams can coax the melanin up from the lower layer to the surface layer of the skin. This is. what gives us a sun tan.
The thin upper layer of the skin is called the epidermis. It is the dry layer which peels off when we try to tan too fast. As it goes, it takes our sun tan with it. The epidermis is really a papery shield over the true skin, which is called the dermas. It is always peeling and flaking off though usually we do not notice it. This is why we lose our sun tan when we stay indoors for a few days.
The true skin is much. thicker and much more alive than the epidermis. It teems with nerves, blood vessels and various glands. The surface of the dermas is a mass of tiny grooves and ridges, pits and bumps, The epidermis has grooves where the dermas has ridges and pits where the dermas has bumps. The two fit together perfectly, which prevents the epidermis from falling off before a new outer skin is ready underneath to take its place.
Sun bathing is goad for the whole body. Vitamin D and other valuable substances can be absorbed by the skin directly from sunbeams. But Mother Nature is always teaching us to be gentle and never to take too much of anything, hoe all know what happens when we gabble up too much sunshine on the first hot day of the year. We get a painful sun burn. The poor epidermis gets a tan all right, for the energetic sunbeams coax the melanin up from the epidermis below. But it also gets fried to a crisp. It dries up tight and has to peel off before it is ready ‑ taking our lovely tan with it. it pulls and hurts the dermas below and we have a very care skin.
The trick is to get n regular dose of sunshine on the skin every day, weather permitting. The sunshine of a snowy winter's day can give a tan like the summer sunshine. Each day, a little of the brown melanin dye is coaxed up into the epidermis whore it shows and each day a little of the epidermis scuffs off, taking a little of the tan with it. So, if you get some sunshine every day of the year you can keep your lovely sun tan summer and winter.