Surely, you have noticed the tall poles along the roadside. Do you know what is on top of those poles? Thats right, wires that carry electric current. These wires carry electric current to your home. But what is electric current? Electric current is actually the flow of electrons. You may recall, an electron is the outer-most particle in an atom. They have a negative charge. Electricity is the continuous flow of these particles. Electrons are able to move through wires. Their speed can even be measured. The SI unit for electric current (or speed) is the ampere (A). Ampere is often shortened to amp. Electric current may flow in just one direction, or it may keep reversing direction. Direct current (DC) flows in only one direction. Direct current is what is used in devices like flashlights. Alternating current (AC) flows in two directions. This is the type of current that flows into your home through wires.

Electric current is a flow of electrons. Do electrons have a negative or positive charge?

You might want to know how cold it is. You may need to know how fast the wind is blowing. Maybe it rained last night? Do you know how much? Does it feel humid to you? You have heard all these questions before. To answer these questions, we need data. That data comes from special tools. These tools collect data about the weather. You can see some of the common tools listed below: A thermometer measures temperature. An anemometer measures wind speed. A rain gauge measures the amount of rain. A hygrometer measures humidity. A wind vane shows wind direction. A snow gauge measures the amount of snow.

How is weather measured?

Before the mysterious disappearance of one of its passenger jets this month, Malaysia wasn't a country used to finding itself dominating headlines around the world. Some of its Southeast Asian neighbors, including Indonesia and the Philippines, have suffered devastating natural disasters in recent years and are all too familiar with the media frenzy that accompanies a major crisis. But Malaysia has largely managed to stay out of the international spotlight since its independence from British colonial rule more than half a century ago. "It is one of these countries, because of its geography, that doesn't have earthquakes," said Ernest Bower, senior adviser for Southeast Asia studies at the Center for Strategic and International Studies. "It doesn't have tsunamis. It hasn't been tested with a disaster like this." The disappearance of Malaysia Airlines Flight 370 has thrust the government into the dazzling glare of worldwide attention. And it hasn't emerged with very good grades. "I think on a stress test, they're failing," Bower told CNN's Jake Tapper, pointing to the government's coordination of different agencies and communication with other countries. China among critics Criticism and complaints have come from other countries involved in the search for the missing plane, including China and Vietnam, and from the relatives of passengers. Malaysian officials have created confusion by issuing contradictory statements on key aspects of the investigation. The majority of the people on board the plane were Chinese, and Beijing has increasingly voiced its displeasure with the search, especially after Malaysia announced over the weekend that evidence suggested the plane had been deliberately flown west into the Indian Ocean, away from its last confirmed location over the South China Sea. "The new information means the intensive search in the South China Sea for the whole past week was worthless and would never bear fruit," said a commentary published by China's state-run news agency Xinhua. "Even worse, the golden time for saving possible survivors, if any, was generously wasted."
Of what nationality were the majority of people aboard Malaysia Airlines Flight 370?