Bob Coutts



 A  tornado   is a large, vertical, whirling air mass hundreds of meters across. Wind speeds in a tornado can go well over a hundred kilometers an hour!!. These highly destructive whirlwinds are created when upper level air masses have much different air pressure than the air pressure at ground level. The higher pressure air rises up through the intermediate level air, whirling as it rises much like an up-side down drain in a sink. The power of this whirling air mass is such that whole neighborhoods full of houses can be destroyed and blown up into the sky along with everything in them!.


Hurricanes are extremely large, flat whirling air masses, usually hundreds of kilometers across.  Many hurricanes are bigger than Texas !! The wind speed in a hurricane can reach more than two hundred kilometers an hour  and the destruction a hurricane can wreck on the land can extend over several states and cost several billion dollars. Hurricanes  come into being over the ocean far out to sea.  The destruction occurs when the high speed hurricane winds reach land and blow down structures and vegetation. One of the VIRTUAL EXPERIMENTS you will be able to do here, is to learn how to detect hurricanes before they are reported on the news by monitoring cloud movement.



Lightning is the discharge of extremely large amounts of static electricity between clouds and the ground. The voltages for these enormous sparks can reach well over a million  volts !!!  If a lightning bolt hits a tree, the thermal energy released into the tree can cause the sap in the tree to turn into high pressure steam and the tree literally explodes. Lightning rods connected to heavy cables are mounted on top of tall buildings in lightning country, to provide a safe path for the electricity to dischargto ground. If the lightning discharges through the building, the heat from the current flow could cause the building to burn.



Clouds are made when water molecules in  warm,  humid air slow down as the air is cooled.  When the molecules slow down and stick together, they form micro-drops. As these micro-drops cool even further as they rise higher into the cooler atmosphere, they congeal, forming  water droplets large enough to reflect light. These droplets make up bright white clouds like the ones in the picture on the left. If  the cooling process continues, then the congealing droplets get  even larger. The bigger droplets absorb light, making the cloud darker, as toward the bottom of the picture When the droplets get very large, the air can no longer hold them up and they fall, making rain. If an up-draft ( an upward wind ) pushes them up further, the drops can get very large. If the temperature gets cold enough in the upper atmosphere, they can freeze, making hail.

       As a WEATHER OBSERVER, you can either measure weather elements directly or use Internet resources to acquire information collected by other observers. Several sites on the Internet contain daily measurements which you can print out for your records. One of the most useful types of information is pictures  of cloud cover all over the world. These pictures enable you to see weather patterns travel across the globe.  Local weather  information is important to every one and is up-dated frequently as conditions change. Everyone is interested in the weather ! In addition to up-to-date pictures of cloud cover, beautiful pictures of all different kinds and types of weather phenomena  are available: tornadoshurricanes, thunderstorms, lightning, snow levels, rainfall amounts, cloud types, and  other exciting weather elements. Much of the change in our weather comes about as a result of  the sun's influence on the earth's upper atmosphere. Energy from the sun arrives in the atmosphere and changes its properties . The sun influences both weather here on earth and space weather between here and the sun. Visit the Internet to see where the energy comes from to make changes in our atmosphere, when these changes happen and what happens when the sun's energy reaches the Earth. See if, through daily observations of Earth weather and space weather, you can make a connection  between the two! Welcome to the world of  our Earth's WEATHER!
Hurricane  a large, spinning, spiral shaped, flat air mass  hundreds of kilometers across with speeds exceeding hundreds of kilometrs  per hour
Tornado  a tall spinning column of air, close to a kilometer across, with air speeds of up to one hundred or more kilometers per hour
 air pressure in the atmosphere
Lightning  discharge of static electricity between the ground and clouds
Space weather  conditions in space between earth and the sun, determined by discharge of energy and charged particles from the sun 
Humidity  the relative amount of water molecules in the air

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