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Making Towers Bird-Friendly

The lights on tall communication towers warn pilots to avoid the towers when flying at night. Unfortunately, the steady red lights often used on towers have the opposite effect on birds: the bright beams attract and confuse them. Instead of avoiding the lights, the birds fly directly toward them, crashing into the towers or becoming entangled in power lines. Millions of birds have died this way. However, there is a solution. Unlike steady lights, flashing or blinking lights don't attract birds. In response to demands from conservation groups, the Federal Aviation Administration in 2016 began requiring communication towers in the U.S. to use blinking lights instead of steady ones.

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AC vs. DC

In the 1880s, the War of the Currents began. Thomas Edison developed direct current, or DC, a type of electricity that flows in one direction. By 1887, DC was in use around the United States. It had some drawbacks, though. Converting it to lower or higher voltages was difficult; that is, the current's force couldn't be changed easily. Transmitted at the low voltage needed for use in homes and businesses, it lost power after traveling only a mile. Meanwhile, Nikola Tesla was working with alternating current, or AC. AC reverses direction many times per second and can be changed to different voltages. At high voltage, it can be transmitted efficiently, traveling hundreds of miles with little energy loss. Because of its advantages, AC triumphed by the end of the nineteenth century.

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The Importance of Japan's Cherry Blossoms

In the northeastern United States, autumn is particularly colorful. Leaves change from green to red and orange, and many Americans take scenic fall foliage trips. In Japan, a similar phenomenon takes place in the spring. Cherry trees erupt in a shower of pink, and the entire country celebrates the arrival of sakura, or cherry blossoms. Though autumn leaves are admired in the United States, they are seen as just a pretty seasonal display. In Japan, on the other hand, cherry blossoms have much greater significance; the flowers are deeply rooted in Japan's culture and philosophy. Since as far back as the eighth century, sakura have symbolized change and beauty, new beginnings, and the circle of life. The blossoms have been celebrated in Japanese paintings, poems, and tea ceremonies for centuries.

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