Subj : Re: Wegman's To : Barry Martin From : Nancy Backus Date : Fri Sep 20 2019 01:08:16 -=> Quoting Barry Martin to Nancy Backus on 12-Sep-2019 15:45 <=- BM>>>> I got interested in the 'Millikan Oil Drop Experiment' somehow when I BM>>>> was probably in Junior High, maybe late elementary school. Have a BM>>>> book (wonder if packed away in a box in NH?) which explains it, plus BM>>>> how to build one's own. Was going to. NB>>> And possibly the book you have is out-of-print now, too... :) NB> (snip) BM>> That I'm fairly certain of: received in the late 60's/early 70's, so BM>> around 50 years ago. LIS it didn't occur to even look for it. NB>> Is it something that your mother might be able to locate for you...? BM> Probably not other than "might be stored in this bookcase". I BM> couldn't give a description of the book the project as in; easy enough BM> to get the experiment plans on-line, just might have other stuff of BM> interest in it. And sometimes the old project plans have the parts I BM> have in stock. (I still have a bunch of tubes stored away.) Still, somewhat of a possibility, one way or another... ;) NB>>>> He's been back since... and while you were gone, did post quite the NB>>>> treatise on thunderstorms.... I saved it to a textfile for reference NB>>>> later, although it didn't exactly answer our wonderings... :) BM>>> Oh Daryl!! NB>>> Didn't you see the message I referred to....? It was from Daryl NB>>> to me... As I said, I did save it... did you want a re-post...? BM>> Ahh.. yes, please! NB>> Ok... It will have to wait until I'm back home now... it's not on the NB>> laptop.... :) If I don't think of it right away, this message will NB>> remind me... BM> Probably will! And it indeed did... so, forthwith.... here's the message: Ä Area: ILink - Friendly Talk ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Msg#: 1246 Rec'd Date: 31-Jul-2019 15:55 From: Daryl Stout Read: Yes Replied: No To: NANCY BACKUS Mark: Subj: Thunderstorms Was: Wegman ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Nancy, NB> NB>> More often, we just get snow.... just like we often just get rain NB> NB>> (even very heavy rain) without any thunder/lightning.... :) NB> BM> True. Maybe when Daryl gets back he'll explain it to us. NB>I don't think I've seen him jump in on this yet... Maybe we should look for Jim Cantore. Seriously, if you have enough lift and instability, along with charged particles in the cloud, you're going to get lightning and thunder. The type of precipitation is determined by the air temperatures aloft, at the mid levels, and at the ground level. 1) Below freezing at the surface, midlevels, and aloft: SNOW -- the closer to freezing it is, may determine the difference between a heavy, wet snow, and a dry, powdery snow. I forget which one is better for making snow cream and a snowman with (never mind Calvin and Hobbes with his anatomically correct creations ). The dry powdery snow is best for skiing, but in the mountain areas, a large amount of such could lead to deadly avalanches. 2) Below freezing at the surface (shallow layer), above freezing at the midlevels, and below freezing aloft: FREEZING RAIN or FREEZING DRIZZLE. This is the most dangerous, as it puts a GLAZE on EVERYTHING -- trees, power lines, bridges/overpasses, sidewalks, etc. Widespread downed trees, power lines, and power outages result...sometimes for several weeks. If more than 1/4 inch of ice accumulation is forecast, it's known as an "ice storm". Back to back ice storms in Arkansas in 2000, had portions of north Arkansas in the dark for 6 weeks!! 3) Below freezing at the surface (deep layer), above freezing at the mid levels, and below freezing aloft: SLEET (also known as ice pellets). This isn't as dangerous as freezing rain, but it can still make things slippery. 4) Above freezing at the surface, and either above or below freezing at the midlevels and aloft: RAIN What you mentioned is known as "VIRGA"...where the precipitation evaporates before reaching the ground. You can still get the lightning and thunder, but there is dry air at the low levels, and at the base of the storm, that the precipitation dissipates on the way down. Once the lower levels moisten up, then precipitation reaches the ground. Doppler Radar may indicate it's raining, but surface observations note that it's not. Now, the first stage of a storm is known as the cumulus stage. Moisture rises and condenses into clouds...basically, the entire storm is composed of updrafts. Inside the cloud, particles of dust, dirt, etc., known as condensation nuclei, attract the water droplets, which bump into each other, and grow larger. This is known as coalesence. Over time, the weight of the water droplets in the cloud become too heavy to be supported and held aloft by the updrafts, so they fall, creating a downdraft. Some thunderstorms can have as much as 500,000 tons of water or more!! Lightning is basically a massive discharge of static electricity. In a thunderstorm, negative electrical charges buildup from the condensation nuclei bumping into each other. These negative charges, usually at the base of the storm, induce positive charges in the higher levels of the storm, and on the ground for several miles around the storm. Finally, the build up of charges becomes so great, that the air can not insulate them from one another, and you get lightning. All lightning can be deadly, and you never know where it'll strike next. But, you have lightning within the thundercloud...lightning from cloud to cloud (from one storm to another)...lightning from cloud to air (a bolt from the blue)...and cloud to ground. Some thunderstorms can be prolific lightning producers. It only takes one lightning strike to cause damage, injury, or death. I'm a 2 time lightning strike survivor myself, and have nervous system as a result. The strikes were indirect, but I still got the shock...however, I carry no electrical charge, and can be handled safely. Each lightning bolt: 1) Is 50,000 degrees Fahrenheit (5 times hotter than the sun's surface). 2) Has 3 million volts and 300,000 amps of electricity (not even 1 amp of electricity will kill you). 3) Is as wide as your thumb, but can be 5 miles long. 4) Can strike from 20 to 200 miles from the parent thunderstorm. The thunder is the rapid expansion of the air in the lightning channel. If it sounds like a sharp clap, boom, or explosion, the strike was likely very close to you. If it sounds like a low rumble, the storm is a few miles away. Regardless, if you hear thunder, you are close enough to be struck by lightning...and if you're outdoors, you need to STOP all activities IMMEDIATELY!! Lightning does NOT need to strike twice!! Tbe best way to remember it is "The 30-30 Rule". The first part means that if less than 30 seconds elapses after you see lightning before you hear thunder, you are close enough to be struck by lighnting. The second part means that if 30 minutes has elapsed since you last heard thunder, you can resume all normal activities. Back to the thunderstorm itself, at this point, the storm is mature. Heavy rain falls from the storm, causing urban and flash flooding; especially if several thunderstorms move over the same area (known as "training", like a train repeatedly going down the tracks). Strong winds fan out at the base of the storm, and if above 58 mph (the criteria to class a storm as severe), it's known as downburst or straight line winds, which can cause damage similar to an EF-0 or EF-1 tornado. There's also lightning (some storms have very little, but others seem to have an unending supply). If the storm is intense enough with strong updrafts, rain droplets are swept to the upper reaches of the storm, where temperatures are below freezing. These super cooled water droplets freeze, and form hailstones. Depending on how strong the updraft is, the hailstone may make several trips up and down the storm, before it becomes too heavy for the updraft to support, and it rockets to the ground at 100 mph. Hailstones can range from 1/4 inch diameter, to the size of a grapefruit (4 1/2 inches in diameter). At 1 inch in diameter, it can hurt or kill you, and that's the criteria for a severe thunderstorm. The largest hailstone ever recorded was in South Dakota or Nebraska, at nearly 9 inches in diameter!! If you're in an areas with large hail, you're in or near an area where tornado development may occur. Speaking of which, if the storm is "surface based", and there's a turning of the winds with height, the storm may rotate. At this point, it's known as a "supercell"...and it likely to spawn tornadoes. This element is known as wind shear...such as southeast winds at the surface, southwest winds at the mid levels, and west winds at the upper levels...the wind is turning with height. If the shear is extremely strong, strong to violent, long track tornadoes, may develop. In the case, the tornado can be a mile wide, if not bigger...and be on the ground for hundreds of miles. Finally, the updraft weakens. The downdraft takes over, and the thunderstorm collapses in on itself. This is when you get intense flooding rain, and strong downburst winds. However, the cool air left by the storm may create an outflow boundary, where new thunderstorm activity may form later on. And, that's Meteorology 101 for today. :) Daryl === ž OLX 1.53 ž We all have to go sometime -- where's the toilet?? ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ As I said... it was quite the treatise.... ttyl neb .... If you want your boomerang to come back, throw it first...! --- EzyBlueWave V3.00 01FB001F * Origin: Tiny's BBS - http://www.tinysbbs.com (454:1/452) .