Category Kids Queries

That old saying is a sham. Bolts strike skyscrapers and other tall buildings twice, thrice, or more. New York City’s Empire State Building gets hit about 100 times each year.

When we see a lightning strike, we’re witnessing the discharge of electricity that has built up in a cloud, which is so strong that it breaks through the ionized air. This creates a stepped leader, or the lightning bolt, that travels downward until it reaches the ground. It is an incredibly quick process that takes only about 30 milliseconds. And right after lightning strikes, it reverberates in quick succession. So, essentially, multiple strikes can happen at the same place in this short period of time. Technically, the lightning is already striking more than once. Even during the same thunderstorm, there is nothing stopping a lightning bolt from striking the same place it had struck previously, even if it was as little as a few seconds earlier or as much as centuries later.

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The odds of the average American getting struck are 1 in 5,000. Lightning strikes about 2,000 people world-wide each year, and 9 out of every 10 victims survive with symptoms ranging from memory loss to dizziness to bizarre scars.

Lightning can kill people (3,696 deaths were recorded in the U.S. between 1959 and 2003) or cause cardiac arrest. Injuries range from severe burns and permanent brain damage to memory loss and personality change. About 10 percent of lightning-stroke victims are killed, and 70 percent suffer serious long-term effects. About 400 people survive lightning strokes in the U.S. each year.

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Ever notice how most batteries have little plus symbols (+) on their tops and minus symbols (-) on their bottoms? A storm cloud is like a big fluffy battery – the most powerful battery on Earth. Drops of rain and bits of ice blow and fall within the cloud, bumping against one another to create static electricity. Positively charged particles rise to the cloud’s top, while negatively charged particles sink to the lower levels. The difference between the positive and negative particles builds up a current, which arcs through the air as intra-cloud lightning, the most common type of lightning.

The much more dangerous cloud-to-ground lightning works its way downward from the negatively charged lower levels of a cloud (or, in some cases, from the positively charged tippy-top) through a stepped leader, a series of negative charges. The trip down the steps happens faster than the blink of an eye: around 200,000 mph (322,000 kph). Once the stepped leader gets within 150 feet (46 m) or so of the surface, it connects with a positive jolt of electricity that rises through an object on the ground, such as a tree, tower, building, or even you (if you’re silly enough to stand outside during a storm). This upward surge is called a steamer, and it’s the flash of lightning you see with your eyes. When it connects with the leader, it creates a channel to conduct electricity from the earth to the cloud. Zzzzzt! Krakow! Lightning can carry up to a billion volts of electricity – about 50,000 times the current of a typical industrial electrical accident.

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From frigid ice ages to globe-spanning heat waves, Earth’s climate has been subject to natural changes throughout its long history. But in the last century or so, temperatures have risen so quickly and consistently that scientists are now certain the causes aren’t natural. Why is it happening? Humans burn fossil fuels (coal, oil, and natural gas) to power their homes, cars, planes, and factories. This creates carbon dioxide, which occurs naturally in the atmosphere (animals exhale carbon dioxide, and plants need it for photosynthesis). A so-called greenhouse gas, carbon dioxide traps heat in the atmosphere. Human activity is adding so much extra carbon dioxide to the atmosphere that it’s causing an artificial climate change – a rapid rise in temperatures across the globe. The decade of 2001-2010 was the warmest ever recorded worldwide.

The rise in global temperatures will cause more than some hot summers. Effects of climate change include:

1. The melting of glaciers and ice caps, resulting in catastrophic sea-level rises. Low-lying cities and coastal areas will flood.

2. An increase in the instances and unpredictability of ‘’extreme weather,’’ such as hurricanes and tornadoes.

3. Longer dry seasons and droughts that will wipe out crops, leading to starvation.

The side effects of climate change will only lessen if humans switch to alternate energy sources (such as solar power), reducing their carbon footprint.

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Two reasons: strong winds and storm surge (the crashing of waves inland). So to understand the answer to this question, you first need to know what causes wind and waves. Temperature differences in the atmosphere create changes in air pressure. Wind is the movement of air from areas of high to low atmospheric pressure. Waves, meanwhile, are created by wind blowing over a body of water. Those tube-shaped ‘’barrels’’ that surfers ride off the north shore of Hawaii? They were created by wind blowing on the ocean’s surface thousands of miles away.

Now, hurricanes typically take shape over tropical oceans and coasts, where the warm ocean waters create an area of low pressure in the moist air. Bundles of thunderstorms form, fueled by the warm ocean temps and whipped into a swirling shape by the Earth’s rotation and growing wind. What starts as a ‘’tropical depression’’ becomes a ‘’tropical storm’’ when the winds reach 39 mph (63 kph). When the winds top 74 mph (119 kph), the storm is officially declared a hurricane.

Hurricane winds can reach 150 mph (241 kph), tearing apart houses and tossing cars. When these massive storms hit land, they bring flooding rain and sometimes spawn tornadoes. Even if a hurricane never makes landfall, its wind can create massive waves three stories high that crash ashore as deadly storm surge.

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Earth’s crust rides on a sea of molten rock called magma, which bubbles to the surface wherever two plates meet. Earthquakes work like pressure valves for this magma (known as lava when it reaches the surface). In ‘’effusive’’ volcanoes (such as the famous volcanoes of Hawaii, U.S.A.), the lava flows at a steady rate, often forming new mountains and islands. Volcanoes with a lot of gases dissolved in their magma and a high content of a chemical known as silica have ‘’explosive’’ eruptions in which they literally blow their tops. Potentially much deadlier than effusive eruptions, explosive volcanoes vaporize the landscape in every direction with hot gas and carpet the terrain with choking ash. The explosive eruption of Mount Vesuvius in A.D.79 destroyed the ancient Roman town of Pompeii, burying it under 13 to 20 feet (4 to 6 m) of hot ash. The geyser-riddled Yellowstone National Park in Wyoming, U.S.A., sits above a ‘’supervolcano’’ that last blew its top 640,000 years ago.

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