ScienceIQ.com

How Sublime

Show of hands. How many of you can't resist playing with dry ice? Dry ice is carbon dioxide frozen to -109.3 degrees F (-78.5 C). Throw a piece in water and it bubbles and boils. Expose a piece to air and it turns into white fog. The thing that makes dry ice do these tricks is a process called sublimation. ...

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DryIce
Biology

The Self-less Gene?

The dictionary defines altruism as 'an unselfish concern for the welfare of others.' That's the kind of behavior that rescue workers showed in the 9-11 attack on the World Trade Center, and many of ... Continue reading

SelflessGene
Astronomy

Crab Nebula

For millions of years a star shone in the far off constellation of Taurus. So far away, and so faint that even if our eyes were ten thousand times more sensitive, the star would still not be visible ... Continue reading

CrabNebula
Engineering

Airbags

An automobile airbag is a safety device: its sole purpose is to prevent an occupant of the vehicle from impacting with the surrounding structure. Typically, in a collision, Newton's laws of motion ... Continue reading

Airbags
Biology

Batesian Mimicry

If you ever got stung by a wasp you would probably avoid all flying insects which resemble the brightly-colored yellow and black wasp. If you were a bird and certain types of butterflies gave you a ... Continue reading

BatesianMimicry

What Causes Wrinkles?

WhatCausesWrinklesElastin and collagen are proteins in the skin's underlying layers that give it firmness and elasticity. As we age, skin begins to lose its elastin fibers. The fibers start to tangle in disorganized masses as blood vessels shrivel, robbing skin of oxygen and nutrients. Thinning and degeneration of elastin over time cause wrinkles, 'worry' and 'laugh' lines, sagging, and crepey rippled skin. Aging skin also loses collagen at the rate of about one percent each year--and even faster if exposed to sunlight. The loss of collagen causes skin to sag and droop. Gravity, the slackening of muscles, and the loss of collagen all contribute to the sagging, wrinkling skin of advancing age.

After age fifty, the loss of both bone and fat beneath the skin lets the skin sag in the loose folds and wrinkles of old age. As we grow older, a drop in hormone levels causes the skin's outer layer to grow thin, giving that shiny parchment appearance of old age. The amount of moisture in the skin declines, so skin cracks and loses suppleness. The outer skin layer thickens--especially if exposed to the sun--becoming rough and scaly. The rates of making and shedding skin cells slow, and the repair of damaged cells becomes less efficient. Sebaceous glands produce less oil, leaving skin rough and dry. The number of pigment-producing cells declines, causing skin to tan poorly and freckle easily. Patches of brown, called 'liver spots' or 'age spots,' appear often on face, neck, or hands. Cancers of the skin become more likely.

Visible changes at the surface are accompanied by changes in the skin's deeper layers. There, blood vessels decline in number, slowing circulation and increasing sensitivity to heat and cold. The amount of collagen decreases and its structure changes, so the skin tears easily. Loss of collagen support for blood vessels means skin bruises more easily and wounds heal more slowly. As great as these changes are, many experts think they are not so much a result of aging as they are consequences of exposure to the sun. They say the best way to maintain youthful skin is to stay out of the sun.