What is the relationship between skin reflectance and latitude?
Among males, skin reflectance increases roughly 8.2% for every 10 degrees of latitude in the Northern Hemisphere but only 3.3% for every 10 degrees of latitude in the Southern Hemisphere. Among females, the corresponding numbers are 8.1% in the Northern Hemisphere and 4.7% in the Southern Hemisphere.
Why is human skin reflective?
It has been estimated that 4% to 7% of visible light is reflected from the surface of the skin, independent of wavelength and skin color. The remaining light is refracted as it passes from air into the skin. The primary sources of particulate scatter within the skin are filamentous proteins.
Can skin be reflective?
The ability of skin to reflect UVR decreases rapidly with decreasing wavelength. Reflection is as high as 20% for 400 nm and falls below 1% at 280 nm. Average UVA (315 to 400 nm) reflectance can reach 12%, but is only about 2.5% in the UVB (280 to 315 nm) spectral range.
Why is skin reflectance measured on the inner arm?
7. Why do you think that reflectance data are collected from a subject’s inner arm? The inner arm is not usually affected by environmental factors (e.g., it doesn’t tan). 8.
Does higher skin reflectance mean darker skin?
Lower frequencies represent lower skin reflectance and thus darker pigmentation, whereas higher frequencies represent greater skin reflectance and therefore lighter pigmentation.
Is skin reflectance randomly distributed throughout the globe?
Answer and Explanation: Skin reflectance is not randomly distributed throughout the globe.
How does skin absorb light?
Visible light and skin. Melanin is responsible for skin color and can be found in the epidermis. Melanin partially absorbs visible light, which can cause hyperpigmentation and uneven skin tone. The dermis contains blood vessels that are capable of absorbing blue and green light.
What are the properties of human skin?
The skin consists of three layers of tissue: the epidermis, an outermost layer that contains the primary protective structure, the stratum corneum; the dermis, a fibrous layer that supports and strengthens the epidermis; and the subcutis, a subcutaneous layer of fat beneath the dermis that supplies nutrients to the …
Why is shiny skin attractive?
It is believed that living things find gloss attractive because it can represent water needed for survival and determine the juiciness in fruits. Skin gloss also reflects health conditions. However, it had been unknown which part of the brain finds the gloss texture attractive.
What is radiant skin?
For the purposes of this article, we’ll define radiant skin as smooth, elastic skin with a relatively even tone and texture. Naturally radiant skin also tends to have a subtle, healthy-looking glow (the kind that can’t be faked with a healthy dusting of highlighter).
How does folate affect skin color?
The vitamin D–folate paradigm proposes that skin pigmentation evolved as a balancing mechanism to maintain levels of two key vitamins in human health: vitamin D and folate. In maintaining levels of these vitamins, the roles of these nutrients during reproduction would be preserved.
What is the relationship between the UV index and latitude?
LATITUDE affects UV radiation, which is strongest at the equator and declines toward the poles. ALTITUDE affects UV radiation; UV increases about 2% for every 1,000-foot increase in elevation due to thinner mountain air. CLOUD COVER, if heavy, can block most UV radiation.