Our Window on Nature

When the weather turns so frightfully cold that we don parkas and boots before venturing outside, how do plants and animals survive? They can’t add layers of clothing. They can’t toast their tootsies before a fire. They’ve never even heard of hot chocolate.

Scientists focus on two coldweather survival strategies that are used by living organisms, including man: avoid the cold if you can, and if you can’t, hunker down and endure it. Each plant and each animal devises its own variation on those themes. (Read the rest …)

Love it or hate it, when snow season appears much of the country is covered with a blanket of white. In the northern hemisphere about half of the land area sees some snowfall each year, and every state has experienced at least an occasional dusting of the white powder.

It may be hard to appreciate, looking from the operational end of a snow shovel, but ice crystals and the snowflakes they form are things of beauty, often perfectly symmetrical, sometimes simple, and sometimes wonderfully complex. An ice crystal, as you might expect, is a single crystal made of ice. When two or more ice crystals stick together you have a snowflake. (Some definitions consider a single large crystal a snowflake.)

Ice crystals develop around tiny dust particles in clouds, but unlike raindrops, they bypass the liquid stage. Water vapor, by a process called sublimation, passes directly from the vapor state to a crystal form, taking on the hexagonal (six-sided) shape determined by its atomic structure. As the ice crystal grows, this original shape partially controls the final result. The original crystal becomes larger as nearby water vapor condenses and freezes on its surface. The six pointed ends of the hexagon grow faster than the flat surfaces, often creating a star-shaped object with six almost identical projections or arms. (Read the rest …)

Several times a year we rearrange our sleeping schedules to watch one of nature’s annual fireworks displays. Just like clockwork, during the second week of August, the early morning sky lights up with the castoff particles left by the passage of a comet.

Comets are the vagabonds of the solar system. Many of them travel in an ellipse, coming close to the sun at one end of their orbit, and moving towards the outer solar system at the other end. Although hundreds of comets pass through the inner solar system each year, most are so small that they go unnoticed. But occasionally a big comet travels by. (Read the rest …)

Hot biscuits wouldn’t be nearly as tasty without a liberal layer of honey, and this is the time of year when the local bees get back to work creating more of that magical syrup. After breakfast this morning we did a quick calculation. We just ate the equivalent of the lifetime production of several dozen worker bees.

Honey production is a very bee-intensive process. In order to produce the pound of honey eaten by the typical American each year, it takes bees about 55,000 miles of flight with visits to as many as 2 million flowers. Little by little, blossom by blossom, each worker bee produces only one-twelfth of a teaspoonful of honey. (Read the rest …)

Jules Verne, among others, wrote about the “green flash,” but the first time we read about it, we concluded that it seemed about as likely as traveling 20,000 leagues under the sea. It was called “an intense spark of colored light visible at sunrise or sunset” – sure, with Nessie rising to greet it, no doubt. However, after considerable research we decided that if the green flash does not exist, it is a hoax that has survived for a couple thousand years.

Assuming that the right atmospheric conditions are present, along with a view of a distant horizon, and the sun sinking toward its nighttime rest, scientists explain the phenomenon as follows. Consider a prism and the way it splits light into its component colors. The green color comes from a leftover ray of sunlight still hanging in the sky after the red, orange, and yellow have dropped below the horizon. The blue and violet rays are scattered invisibly in the atmosphere, leaving a clear emerald green just at the edge of the sun – the same green rim we’ve seen many times when ignoring parental admonitions to “Stop looking at the sun. It will ruin your eyes! ”

(Read the rest …)