My Science School

Haloclasty is a type of physical weathering caused by the growth of salt crystals. The process is first started when saline water seeps into cracks and evaporates depositing salt crystals. When the rocks are then heated, the crystals will expand putting pressure on the surrounding rock which will over time splinter the stone into fragments.

Salt crystallization may also take place when solutions decompose rocks (for example, limestone and chalk) to form salt solutions of sodium sulfate or sodium carbonate, from which water evaporates to form their respective salt crystals.

The salts which have proved most effective in disintegrating rocks are sodium sulfate, magnesium sulfate, and calcium chloride. Some of these salts can expand up to three times or more in volume.

It is normally associated with arid climates where strong heating causes strong evaporation and therefore salt crystallization. It is also common along coasts. An example of salt weathering can be seen in the honeycombed stones in sea walls.

Credit: Wikipedia

Picture Credit : Google 

The presence of water and changing temperature. Weathering happens less in very hot and dry areas, as well as places that are extremely cold and dry, where the temperature does not change much.

Weathering is a natural process, but human activities can speed it up.

 For example, certain kinds of air pollution increase the rate of weathering. Burning coal, natural gas, and petroleum releases chemicals such as nitrogen oxide and sulfur dioxide into the atmosphere. When these chemicals combine with sunlight and moisture, they change into acids. They then fall back to Earth as acid rain.

 Acid rain rapidly weathers limestone, marble, and other kinds of stone. The effects of acid rain can often be seen on gravestones, making names and other inscriptions impossible to read.

Credit: National Geographic Society

Picture Credit : Google 

It is a process in which hard rock and minerals on the surface of Earth gradually break down and change form because they are exposed to wind, water, salt and varying temperatures. Weathering is the first step in the formation of soil. There are two types of weathering: mechanical and chemical. In the first type, rocks break up into smaller fragments, whereas in the second, the original material transforms into another substance.

Weathering, disintegration or alteration of rock in its natural or original position at or near the Earth’s surface through physical, chemical, and biological processes induced or modified by wind, water, and climate.

During the weathering process the translocation of disintegrated or altered material occurs within the immediate vicinity of the rock exposure, but the rock mass remains in situ. Weathering is distinguished from erosion by the fact that the latter usually includes the transportation of the disintegrated rock and soil away from the site of the degradation. A broader application of erosion, however, includes weathering as a component of the general denudation of all landforms along with wind action and fluvial, marine and glacial processes. The occurrence of weathering at or near the Earth’s surface also distinguishes it from the physical and chemical alteration of rock through metamorphism, which usually takes place deep in the crust at much higher temperatures.

Credit: Britannica

Picture Credit : Google 

A tornado, also called a twister, is a violently rotating funnel of air, set off by giant thunderclouds called supercells. The vortex, known as a land spout, is a whirling mass of air hanging from the base of the cloud down to the ground, like the hose of a vacuum cleaner. Over water, a tornado forms a water spout. Tornadoes can also occur as two or more spinning vortexes spinning around each other.

Tornadoes are violently rotating columns of air, extending from a thunderstorm, which are in contact with the ground. Tornadoes develop when wind variations with height support rotation in the updraft. Tornadoes come in different sizes, many as narrow rope-like swirls, others as wide funnels.

Across the Plains, tornadoes can be seen from miles away. However, in the southeast, and especially Georgia, tornadoes are often hidden in large swaths of rain and hail, making them very difficult to see and even more dangerous. Visibility is often affected by terrain constraints in Georgia as well.

As stated before, tornadoes come in different shapes and sizes. They are ranked using the Enhanced Fujita scale. The majority of tornadoes which occur are classified as a weak tornado. Usually weak tornados will last for just a few minutes and have wind speeds of 100 mph or less. Some tornadoes intensify further and become strong or violent. Strong tornadoes last for twenty minutes or more and may have winds of up to 200 mph, while violent tornadoes can last for more than an hour with winds between 200 and 300 mph! These violent tornadoes are rare in occurrence.

Credit: NOAA

Picture Credit : Google 

A prolonged winter storm that combines heavy snowfall, strong winds of more than 56 km per hour, and very low temperature, all resulting in very low visibility.

The United States National Weather Service’s winter weather advisory, watch, or warning system helps meteorologists determine whether atmospheric conditions should be classified as typical winter weather, a snowstorm, or a severe blizzard.

In order for meteorologists to classify a winter storm as a snowstorm, the air temperature high in the atmosphere and near the ground must be below 0°C (32°F). There also needs to be enough water vapor in the air to form snowflake crystals. While snowstorms do not typically last very long (less than a few hours), they can bring high snow accumulations, which can be hazardous.

For a snowstorm to be considered a blizzard, it must also meet specific, though more severe, conditions. To be categorized as a blizzard, the storm must last for at least three hours and produce a large amount of falling snow. Blizzards also have winds measuring over 56 kilometers (35 miles) per hour. These winds cause a large volume of snow to blow around in the air and near the ground, decreasing visibility. Meteorologists will declare blizzard conditions if the snow limits visibility to the point where it is difficult to see an object more than 0.4 kilometers (0.25 miles) away.

Credit: National Geographic Society

Picture Credit : Google 

More than 20,000 people died in the Caribbean during the Great Hurricane of 1780, when winds may have reached a phenomenal 320 km per hour.

Great hurricane of 1780, hurricane (tropical cyclone) of October 1780, one of the deadliest on record in the Atlantic Ocean. More than 20,000 people were killed as the storm swept through the eastern Caribbean Sea, with the greatest loss of life centred on the Antilles islands of Barbados, Martinique, and Sint Eustatius.

The hurricane took place before modern tracking of tropical storms began, but historical accounts indicate that the storm started in the Atlantic and on October 10 reached Barbados, where it destroyed nearly all the homes on the island and left few trees standing. Witness reports in Barbados and Saint Lucia claimed that even sturdy stone buildings and forts were completely lost to the wind, with heavy cannons being carried hundreds of feet. The storm traveled northwest across the Antilles, causing destruction throughout the region; on some islands entire towns disappeared. The storm ravaged Martinique, taking an estimated 9,000 lives. On the island of Sint Eustatius an estimated 4,000 to 5,000 people were killed. During this time, European naval forces were concentrated in the Caribbean because of the American Revolution, and both British and French forces sustained particularly large losses, with more than 40 French vessels sunk near Martinique and roughly 4,000 soldiers dead. As the storm continued north, it damaged or sank many other ships that were returning to Europe.

Credit: Britannica

Picture Credit : Google 

A hurricane is a giant, spiralling tropical storm in the Atlantic Ocean that can reach wind speeds of over 257 km per hour and unleash more than nine trillion litres of rain! It begins as thunderstorms that are set off by moist air rising over the warm ocean. If the water is warm enough, the thunderstorms join together, growing bigger as they begin to spiral across the ocean. As the hurricane grows, it spins faster and tighter around its centre, or 'eye', which remains a very calm area of low pressure. A hurricane can be as much as 800 km across and can take l8 hours to pass over. In the northern Indian Ocean hurricanes are known as cyclones and in the western Pacific Ocean, as typhoons.

Hurricanes are large, swirling storms. They produce winds of 119 kilometers per hour (74 mph) or higher. That's faster than a cheetah, the fastest animal on land. Winds from a hurricane can damage buildings and trees.

Hurricanes form over warm ocean waters. Sometimes they strike land. When a hurricane reaches land, it pushes a wall of ocean water ashore. This wall of water is called a storm surge. Heavy rain and storm surge from a hurricane can cause flooding.

Once a hurricane forms, weather forecasters predict its path. They also predict how strong it will get. This information helps people get ready for the storm.

There are five types, or categories, of hurricanes. The scale of categories is called the Saffir-Simpson Hurricane Scale. The categories are based on wind speed.

• Category 1: Winds 119-153 km/hr (74-95 mph) - faster than a cheetah
• Category 2: Winds 154-177 km/hr (96-110 mph) - as fast or faster than a baseball pitcher's fastball
• Category 3: Winds 178-208 km/hr (111-129 mph) - similar, or close, to the serving speed of many professional tennis players
• Category 4: Winds 209-251 km/hr (130-156 mph) - faster than the world's fastest rollercoaster
• Category 5: Winds more than 252 km/hr (157 mph) - similar, or close, to the speed of some high-speed trains

Credit: NASA

Picture credit: NASA

No, it isn't the study of meteors, although it does involve the study of other sorts of objects that fall from the sky. Meteorology is, by definition, the study of Earth's atmosphere. The root of meteor is a variation on the Greek meteoron, which is a term dealing with any objects that originate in the sky.

Meteorology is an extremely interdisciplinary science, drawing on the laws of physics and chemistry (among others) to aid in our understanding of Earth's atmosphere, its processes, and its structure. It is a study that dates to ancient times, when ancient civilizations made observations and kept records of weather conditions, both for agricultural purposes and out of a general curiosity about the world around them.

Over the centuries, the atmosphere has been studied for a variety of reasons, including agricultural knowledge, military defense and planning, and developing better warnings for severe weather systems like tornadoes and hurricanes. Technological advances, such as the development of scientific computing and an increase in the total number of meteorological observations being taken daily across the globe, have allowed for better forecasts (or at least the meteorological community likes to think they are better forecasts) and a much better overall understanding of our atmosphere.

Credit: Study.com

Picture Credit : Google

Climatology is the study of the atmosphere and weather patterns over time. This field of science focuses on recording and analyzing weather patterns throughout the world and understanding the atmospheric conditions that cause them. It is sometimes confused with meteorology, which is the study of weather and weather forecasting. However, climatology is mainly focused on the natural and artificial forces that influence long-term weather patterns. Scientists who specialize in this field are called climatologists.

The first studies of climate can be traced back to ancient Greece, but climate science as it is now known did not emerge until the advent of the industrial age in the nineteenth century. The science of climatology grew as scientists became interested in understanding weather patterns. In recent times, climatologists have increasingly focused their research on the changes in Earth’s climate that have occurred since the industrial age. Earth has been growing warmer and warmer as human industry has expanded and released more carbon into the atmosphere. This effect, called global warming, is a particularly important object of study for climatologists. By studying global warming, climatologists can better understand and predict the long-term impact of human-caused climate change.

Credit: National Geographic Society

 

Picture Credit : Google

When water falls from clouds, whether it is in the form of rain, snow, sleet or hail, it is called precipitation. When the Sun heats up water on Earth's surface, the water evaporates and travels into the atmosphere as water vapour. As the air rises and cools, this vapour becomes tiny drops of water again and falls to the ground as rain. If the temperature is below freezing, the droplets form tiny ice crystals that stick together to fall as snowflakes.

Precipitation is any liquid or frozen water that forms in the atmosphere and falls back to the Earth. It comes in many forms, like rain, sleet, and snow. Along with evaporation and condensation, precipitation is one of the three major parts of the global water cycle.

Precipitation forms in the clouds when water vapor condenses into bigger and bigger droplets of water. When the drops are heavy enough, they fall to the Earth. If a cloud is colder, like it would be at higher altitudes, the water droplets may freeze to form ice. These ice crystals then fall to the Earth as snow, hail, or rain, depending on the temperature within the cloud and at the Earth’s surface. Most rain actually begins as snow high in the clouds. As the snowflakes fall through warmer air, they become raindrops.

Particles of dust or smoke in the atmosphere are essential for precipitation. These particles, called “condensation nuclei,” provide a surface for water vapor to condense upon. This helps water droplets gather together and become large enough to fall to the Earth.

Credit: National Geographic Society

Picture Credit : Google

 

The energy (heat) that the Earth receives from the Sun is a major cause of different weather Conditions. The Sun's energy in different parts of the Earth depends on where a place is in the world, the time of year and the time of day.

The energy that the Earth receives from the Sun is the basic cause of our changing weather. Solar heat warms the huge air masses that comprise large and small weather systems. The day-night and summer-winter cycles in the weather have obvious causes and effects.

The effects of currently observed changes in the Sun - small variations in light output, the occurrence of solar particle streams and magnetic fields are very small in the Earth's lower atmosphere or troposphere where our weather actually occurs. However, at higher altitudes, the atmosphere reacts strongly to changes in solar activity. The ozone layer, at an altitude of 25 kilometers (16 miles), and the ionosphere, which extends upwards in a series of layers above 60 kilometers (37 miles), are produced by solar ultraviolet light and X-rays which ionize the thin air at these altitudes. Although the visible light of the Sun is stable, large variations in X-ray and ultraviolet radiation accompany solar activity, and these variations on the Sun cause major changes in the ionosphere. Some meteorologists believe that the ionospheric changes in turn influence the weather in the lower atmosphere, but the physical mechanism by which this may occur has not been definitely identified. There is much research under way or possible relationships between solar activity and the weather.

Credit: A Meeting with Universe

Picture Credit : Google

It is the uniform pattern in which air moves around our planet's atmosphere. It happens because the Sun heats Earth more at the equator than at the poles, and it is also affected by the spinning of the Earth.

Solar radiation that reaches the Earth passes through the atmosphere and is either absorbed or reflected by the atmosphere and Earth’s surface. Most of this absorption happens on Earth’s surfaces, which increases the temperature of both land and water. A small amount of heat in the first few centimeters of the atmosphere is transferred from the surface by conduction, the process of molecules colliding and transferring energy. Because air molecules are farther apart than they are in liquids or solids, they do not collide as frequently as in liquids and solids, and air is a poor conductor of heat. Most heat is transferred in the atmosphere by radiation and convection.

Sunlight absorbed by Earth’s surfaces is re-radiated as heat, warming the atmosphere from the bottom up. This heat is absorbed and re-radiated by greenhouse gases in the atmosphere, resulting in the greenhouse effect. Warmed air expands and becomes less dense than cool air, so warmed air near the surface of the Earth rises up. Cooler air from above sinks and air moves horizontally to replace the rising warm air, which we experience as wind over the surface of the Earth. This transfer of heat because of density differences in air is called convection.

Patterns of air movement are further complicated because of Earth’s spin. Air moving from the equator towards the poles does not travel in a straight line, but is deflected because of the Coriolis effect, adding to the complexity of atmospheric circulation patterns.

Credit: Understanding Global change

Picture Credit : Google 

The weather depends on the way the air moves (wind), the moisture if carries (humidity), and its temperature (warmth). These are controlled by changes in air pressure. As air heats up, it becomes thinner and lighter. It rises upwards, creating an area of low pressure beneath it, which pulls in air from around to fill the empty space. As the air rises, it cools, forming clouds. But the cooler the air gets, the denser and heavier it becomes until eventually it starts to sink. The high pressure created pushes air down towards the ground, causing it to fan out and blow away everything in its way, stopping   the formation of clouds. This is why clear blue skies occur on high air-pressure days.

Weather comes in all different forms, and it changes by the day. It could be sunny one day and raining the next. It could even be sunny, rainy, cloudy, and stormy in one day.

Temperature

It’s getting hot out there. When you talk about the heat of the air outside on a summer day, this is the temperature. Measured with a thermometer in Fahrenheit, Celsius, or Kelvin, the temperature tells you how fast the air molecules and atoms are moving. Fast-moving molecules and atoms mean the temperature is high, while slow-moving molecules in the air create a low temperature.

Humidity

The moisture or dryness of the air is humidity. It’s an important weather aspect. Without it, humans wouldn’t be able to survive. However, the amount of water vapor, or humidity, in the air needs to have balance. Too little or too much water vapor in the air causes health issues and can be dangerous.

Precipitation

Precipitation is just a big word to describe how water falls to the ground. It can be rain, snow, sleet, ice, hail, or drizzle. The form these water or solid particles take depends on other weather factors. For example, if the temperature is cold, below 32 degrees, precipitation comes to the surface in the form of snow. If the weather is nice and warm, water comes down in the form of rain.

Wind

Air moves. All you must do is walk out your door to feel that. The movement of air is created by how the sun heats the Earth, and then convection tells you how air moves in predictable patterns. Therefore, meteorologists have some idea of how a storm will move or the type of weather you’ll have in a week.

Credit: Your Dictionary

Picture Credit : Google 

Meaning "the little girl" in Spanish, La Niña is a climatic pattern caused by a build-up of cooler-than-normal waters in the tropical Pacific, the area of the Pacific Ocean between the Tropic of Cancer and the Tropic of Capricorn. The drastic drop in sea-surface temperature affects patterns of rainfall, atmospheric pressure and atmospheric circulation around the world.

La Niña is a climate pattern that describes the cooling of surface ocean waters along the tropical west coast of South America. La Nina is considered to be the counterpart to El Nino, which is characterized by unusually warm ocean temperatures in the equatorial region of the Pacific Ocean.

Together, La Niña and El Niño are the "cold" (La Niña) and "warm" (El Niño) phases of the El Nino-Southern Oscillation (ENSO). ENSO is series of linked weather- and ocean-related phenomena. Besides unusually warm or cool sea-surface temperatures, ENSO is also characterized by changes in atmospheric pressure.

La Niña events sometimes follow El Niño events, which occur at irregular intervals of about two to seven years. The local effects on weather caused by La Niña ("little girl" in Spanish) are generally the opposite of those associated with El Niño ("little boy" in Spanish). For this reason, La Niña is also called anti-El Niño and El Viejo (the old man in Spanish).

Scientists use the Oceanic Nino Index to measure the deviations from normal sea-surface temperatures that El Niño and La Niña produce in the east-central Pacific Ocean. La Niña events are indicated by sea-surface temperature decreases of more than .5 degrees Celsius (.9 degrees Fahrenheit) for at least five successive three-month seasons.

La Niña is caused by a build-up of cooler-than-normal waters in the tropical Pacific, the area of the Pacific Ocean between the Tropic of Cancer and the Tropic of Capricorn. Unusually strong, eastward-moving trade winds and ocean currents bring this cold water to the surface, a process known as upwelling.

Credit: National Geographic Society

Picture credit: NOAA

Yes, they are. Weather is the state of the atmosphere. Gravity, sunlight, the oceans and landscape influence air movement within the atmosphere, creating new cycles of sunshine, cloud, rain or snow. When looked at over many years, it is possible to see a pattern in these weather cycles, which occur again and again in an area, to define the climate of that area. Weather occurs at a particular time; climate is the average of weather conditions over many years.

More specifically, weather is the mix of events that happen each day in our atmosphere. Even though there’s only one atmosphere on Earth, the weather isn’t the same all around the world. Weather is different in different parts of the world and changes over minutes, hours, days, and weeks.

Most weather happens in the part of Earth’s atmosphere that is closest to the ground—called the troposphere. And, there are many different factors that can change the atmosphere in a certain area like air pressure, temperature, humidity, wind speed and direction, and lots of other things. Together, they determine what the weather is like at a given time and location.

Whereas weather refers to short-term changes in the atmosphere, climate describes what the weather is like over a long period of time in a specific area. Different regions can have different climates. To describe the climate of a place, we might say what the temperatures are like during different seasons, how windy it usually is, or how much rain or snow typically falls.

When scientists talk about climate, they're often looking at averages of precipitation, temperature, humidity, sunshine, wind, and other measures of weather that occur over a long period in a particular place. In some instances, they might look at these averages over 30 years. And, we refer to these three-decade averages of weather observations as Climate Normals.

Credit: NOAA

Picture credit: Google