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This is about science produced by the California Institute of Technology and originally broadcast by station KPCC in Pasadena California. The programs are made available to this station by national educational radio. This program is about weather modification with host Dr. Peter listen and his guest Dr Paul MacCready president of Meteorology Research Incorporated. Here now is Dr. listen one quick thing. You know Johnson once said when two Englishman meet their first objective conversation is the weather. Why he should have selected English for his remark is not clear since the river seems to be a universally compelling topic of discussion between people of any nation. Why should this be sir. Possibly because it happens to be the safest of safe subjects. No one can claim that where there is controversy no one can be accused of it. No one can be blamed for it. Not
until very recently that is. However today we are happy to be able to talk to someone who after 20 years of experiment in research is developing techniques for actually controlling the weather or at least small parts of it in small regions of our earth. Dr Proby McCready Jr. I guess an aerodynamicist physicist was raised and educated in New England a part of the world where weather comes in from and mostly unfavorable. In fact Mark Twain the great humorist once said and I quote There is a sumptuous variety about New England weather that can pilfer a stranger's admiration and regret. The weather is always doing something there always attending strictly to business or always getting up new designs and trying them on the people to see how they will go. But it gets through more business in the spring than in any other season in the
spring says Mark Twain. I have counted one hundred and thirty six different kinds of weather inside of 24 hours. Well after his undergraduate degree at Yale in 1947 Dr. McCready moved west where the skies are not cloudy or day and obtained his Ph.D. in aerodynamics in aeronautics from the California Institute of Technology. After graduating he started his own firm MRI which has become a leader in weather research. Prawn has more than an academic interest in the weather. Wind and cloud. He is a well-known glider pilot and apart from conducting some of his thesis research from the cockpit of a glider which sounds to me like an admirable combination of work and play he used his extensive theoretical knowledge and piloting skill to become the world soaring champion in 1956. The only American ever to hold this distinction. Paul can you give us a few words about the
historical background of weather modification. People were concerned that possibility could affect their ability to do this. The most common reference in history books potential fact cause rain during what seems more likely. You're very concerned with Otherwise what do we actually mean when we talk about weather modification.
There are many different definitions of the term. Small house covers over to blast world wide weather. The atmosphere can be seen three years after the event talking together in a concentrated rain making trying to get out of the rain. Things like ordinary outside weather fascinating topic of the sort of milestone in the area.
Take a look at the history. History course of the question of the. Laboratory
matter whether you are in this area. Soaring sort of respect to meteorology getting started. I made a point
of strong. We're just not talk to the other people because of the early porn you mentioned dropped dry ice through the cards as you called it the rain. How does it actually work. Great.
Water to. Start collecting more. Large trigger Chris act like they are pretty
large. Other words as you say and when you talk about the thermodynamic instability we really mean that there are lots of these little. Particles of liquid around which really didn't want to be to quit they shouldn't have been liquid at that time and so if you give them the slightest opportunity then the ice crystals will grow and ultimately the process continues to cause rain. There must be a considerable commercial attraction about the sign of getting rain where you want to pour. Rain water. Of course is just of. Commercial importance all around the world. When people finally realized that one could modify clouds began thinking that maybe we can increase Rane
individual companies trying to do this kind of cloud seeding. To get more rain economic pressure on doing this was really very very green back in the early days of seeding. Of course it is now. Even though very little was known about the subject the economic pressures dictated that the commercial seeding projects. Rather interesting project. So the first project
of this project to turn projects were not yours. Change your mind again think. Reduce those large effects right conditions effects from the early hours of course recognizing which is quite different. You know Paul you have talked about seeding and the seeding of the cards and getting the dry ice particles up there but how do you actually get these dry ice particles into the cloud.
When you're doing dry eyes you have to go where the cloud is super cool freezing in most cases this requires going up and having a. Technical advance that large scale. So these discoveries of little silver iodide crystals were very close to respect. Ice crystals sort of nature into thinking there were ice crystals. So ice would grow on Friday. Crystals can be produced quite simple burners just very very simple small devices that these generators just release the material into the air.
Those along with the wind. But if there is potential for rain around me there are good up currents many of them starting from the ground and the material will be up in just the right part of the car because it's the core of the cloud. Some air from surface precipitation does tend to form. It's hard to realize that this little generator just looking like a small torch. He has such a potentially such a tremendous effect on gram of material it can release in the atmosphere in certain circumstances. So we get some feeling of the enormous energy involved in the cartoon and the actors here are some of the other milestones for example the community think about about seating and where they can crow
today. Quite an example. Scientists practitioners of the heart have a difference of opinion quite often during commercial the scientific community. University scientists very much look down their noses at Commercial Club seaters work was not as scientific as the scientists. For me it's really proper programs going through proper scientific standards
projects. We're much too much and very little in physics. We're really doing so the course of the checkered actual animosity between different camps. Just getting right now. Recently a report by the National Academy of Sciences which looked at bunch of projects together and concluded sure enough when you look at all these different projects together about a 10 percent increase in rainfall.
There are enough projects to get used to this conclusion even though any one project to provide the desired statistical significance. I guess then the scientific community has accepted the idea of cloud seeding and weather control and I suppose blossoming and blooming in the same way that so many other scientific branches are growing today except question. Embracing it seems to be money weather modification groups trying to get their particular weather modification empire.
Aggressively neutral about the field realizing it always surprises me that people in the United States have been so slow to apply these ideas. Is that the case in the rest of the world. Throughout the rather interesting years back. Project for a very much stronger
person. And I took that to common effect slowness of application and as you pointed out the other factors involved are beginning to realize now they can control the weather that the next question is going to concur. The question whether every person in country seems impossible. Some couldn't or could control her absolutely
doing. To me right now whether a lot of the experiments are done for really just what they're doing reached the point where it's much more difficult regulation standpoint. Present circumstance so that future the field is much more. Technical factors and technical factors are really very optimistic about the probability of being able to stop a decrease like earth much more optimistic about things like that in
the next 10 or 15 years to control weather modification capabilities. Political science here says as you point out everyone would agree that the catastrophes of nature like hurrican and tornadoes and hail are bad things but who would agree about whether rain is a good or a bad thing it depends I suppose upon whether you are a surfer or a farmer. What about some of the other aspects of weather concur. For example in Los Angeles itself some what about the concrete of the atmosphere over the city. The high carbon dioxide concentrations that we hear about over many large cities of the United States. This brings up the weather modification a pretty important
subject observing atmosphere and were carefully aware that some time back. My radar was going on there was a source of there was. A much larger
urban area. The weather probably decreasing. Whether your way but we're not a position yet to be able to say just which way this modification has gone. Not many modification would probably be bad for a man because he's been used to living the way it always was over the centuries. Yes you'll probably think that is a form certainly signs that somebody is meddling intentionally as whether he probably knew whether that's something that you don't be dissatisfied with personally. So so we have seen then that we can actually control the weather poor one of the
conclusions briefly wonder what do we see for the future. Crystal 2 Are you sure that. This is true. It looks like the store should other
factors what you're doing. In some far distant place because between different forces in the atmosphere and when you're seeking to increase rainfall in one spot you're probably having long distance hundreds hundreds maybe small objects spread out over a large area which are very important which are almost impossible to detect that sort of thing must be understood. Regulations and weather modification these effects are talking hundreds of miles across state borders that costs national borders very many problems. Difficulty of
manmade rain washes out because of some catastrophe people go on with natural just something to cope with. All these sort of complex non-technical side really not know what is going to happen in the future. There is no government organization set up at the moment that can handle things like this. What form federal regulatory power or should I just don't know. The form of that organization is going to change over the years. Whether we can control it or can't control
the actual doing of proper regulation. Such economic pressure to increase rainfall so that cloud seeding is going to be such a huge cloud formation. Things like seeding is here. Weather modification. We see that after many years many decades of research man has finally understood something about the mechanics of wind rain and weather and how the clouds behave and that we can control the weather today and that the main Christian as puir has pointed out is who is to control the controllers of the weather. Thank you Paul.
About science
About weather modification
Producing Organization
California Institute of Technology
KPCC-FM (Radio station : Pasadena, Calif.)
Contributing Organization
University of Maryland (College Park, Maryland)
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Episode Description
This program focuses on the science behind weather modification. The guest for this program is Dr. Paul B. MacCready.
Other Description
Interview series on variety of science-related subjects, produced by the California Institute of Technology. Features three Cal Tech faculty members: Dr. Peter Lissaman, Dr. Albert R. Hibbs, and Dr. Robert Meghreblian.
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Guest: MacCready, Paul B.
Host: Hibbs, Albert R.
Producing Organization: California Institute of Technology
Producing Organization: KPCC-FM (Radio station : Pasadena, Calif.)
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University of Maryland
Identifier: 66-40-47 (National Association of Educational Broadcasters)
Format: 1/4 inch audio tape
Duration: 00:28:45
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Chicago: “About science; About weather modification,” 1967-07-25, University of Maryland, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC, accessed October 24, 2021,
MLA: “About science; About weather modification.” 1967-07-25. University of Maryland, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC. Web. October 24, 2021. <>.
APA: About science; About weather modification. Boston, MA: University of Maryland, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC. Retrieved from