Science Illustrated

When you step into an air-conditioned room on a hot summer day, the difference is striking. But how is the air cooled? An air-conditioning system functions in the same way as a refrigerator. But where the refrigerator cools only a small, limited space, air conditioning can cool an entire house, shop or office. This is due to the physical principle of evaporation: When a liquid evaporates, it will absorb some of the heat from its surroundings. A liquid refrigerant is directed into an evaporation system in which the pressure is low. This causes the refrigerant to evaporate into a gas, cooling the large surface area of the coils of the system. The cooler air that is created is sent into the room via a blower. The process will generate heat,…

Two basic factors ensure that rain falls in drops rather than in jets. First, rain is generated within droplets in clouds, and second, air resistance rips large amounts of water apart as it falls toward the ground. When warm, moist air moves upward, it gets cooled by the lower temperature of the atmosphere; the resulting vapor condenses into droplets, generating clouds. The droplets are extremely tiny and are so light that they float. In order for the water to collect into a raindrop, a microscopic speck of dust or pollen must also be present in the cloud. Then, the many tiny droplets will settle on the speck and fall to the ground in the shape of a raindrop with a diameter of at least two-hundredths of an inch. The size…

It does not immediately seem as if the other planets of the solar system play any meaningful role in Earth's existence. It's the sun that we orbit that supplies the energy required for life to survive on our planet. But the composition of the solar system and the location of the other planets were vital for life developing on Earth. Specifically, Jupiter's distance from the sun is a critical factor. In many other solar systems, giant Jupiter-like planets have ended up in orbits very close to their star by wandering across their solar systems. Had Jupiter done the same thing, Earth would either have been swallowed by the gas giant or hurled away from the habitable zone. Computer simulations of the development of the solar system also have shown that…

Scientists are reconsidering the conventional wisdom on one of evolution's most important events: when life first came ashore, some 400 million years ago in the Devonian period. The Ichthyostega tetrapod has long been thought a likely candidate for the first vertebrate to trade the sea for land. But examining the animal in a new way yielded a surprising result. A team of scientists led by Dr. Stephanie Pierce of the Royal Veterinary College in Hatfield, England, scanned several Ichthyostega fossils in 3-D and used the data to create an accurate digital copy of the tetrapod. Using animation software, they were able to replicate the way the animal's limbs would likely have moved, as well as measure how far its individual joints could be stretched. By comparing the data with the…

German pharmaceutical giant Bayer and scientists from the Karlsruhe Institute of Technology have developed an “earthquake wallpaper” called EQ-Top. Reinforced with fiberglass, the wallpaper is so strong and flexible that it can prevent brick buildings from collapsing during an earthquake. The wallpaper's strength is due to the paste that was developed to mount the wallpaper. The water-based adhesive contains tiny ball-shaped molecules that can penetrate even the smallest cracks in a surface, where they generate flexible hydrogen bonds that are strong enough to almost glue the wallpaper permanently. When an earthquake strikes, the wallpaper's structural properties allow the energy of the shock to be dispersed across the wall's surface, protecting the weak points around doors and windows. Richter scale: Indicates seismograph displacement at a point 62 miles from the epicenter.…

The first humans to arrive in North America lived rather hardscrabble — and unhygienic — lives. Archaeologist Dennis Jenkins from the University of Oregon discovered this firsthand while exploring eight small rock caves near the city of Paisley, Oregon. There he found copious amounts of fossilized feces, called coprolites, that had been left behind by the caves' inhabitants. They were scattered all over the place, where children and babies would have played on the ground, and even by the fire, where food was cooked. “You can imagine what it smelled like … with … smoldering smoke, urine and feces … blood and bits of meat,” Jenkins says. The poor standards of hygiene are hardly surprising to modern-day scientists, but the people who lived in the caves could never have imagined…