Hey everyone, Mr. Gibson here. I'm ready to teach you your next lesson in cryptography. Today, we're going to be covering how to write a function that'll help us format our output for functions. We've learned so far in this course that plaintext and ciphertext get formatted a little bit differently. It's much easier to use Python to format your plaintext, so we know plaintext needs to be lowercase letters. And if we have kind of raw plaintext that we haven't gone through and inserted the spaces to form actual words, then it's just best practice to leave it kind of all lumped together, one big string, no spaces. So we could do that by just using a dot lower method on our output string. And we can, if you want to be nice about it, we can do a dot replace a space with an empty string, make sure there's no spaces in there. And we're done. We can just use two string methods, simple calls to get those done. Formatting our ciphertext is a little bit harder. We know ciphertext needs to be uppercase. That's easy to do. We can just use our dot upper method. But it's also supposed to be blocked into groups of five. And then that's where things get a little bit trickier. So we're going to take a look at today is how can we write a function that'll help block our text out into groups of five characters with a single space in between. No spaces that lead it and no spaces that end it. So I've got to start it here. We've got a function skeleton laid out here with our documentation string. It shows you that you're going to take in a string of text. That's going to be the text that we're planning to block. So it's not going to try and make any predictions about what it needs to do with that in terms of doing to clean it or anything. We're just going to assume that it's good to go. Everything is done to it ahead of time. We just need to block it. So this is all that this code is going to do. Take that string, block it out correctly. The second input argument is the size variable, which we've made a keyword, an optional keyword argument that's defaulting to the integer five. I thought it would be nice in this function that if for whatever reason we wanted to block it into characters of four in a group or seven in a group, that we could do that. But since the standard default is kind of five, we'll just make that our optional keyword argument default of five. I've initialized a string called block text, which is where we're going to move all of the characters that are contained in the string text. As well as some spaces that we're going to introduce at just the right moment. So let's go ahead and iterate over that string text. We've done this before. So we're going to say four character in text. So we're going to initialize the variable character in the four string, and we're going to iterate over the string text. So one character at a time, one substring at a time from the string text is going to be assigned to the variable character. And we're going to do some calculations with that. And what we want to do is figure out when are we going to introduce the space. So we want to do that in this context, every fifth character that we've iterated over. So there's a few ways that we can do this. What I'm going to be looking for is I want to check to see if the total number of characters that have already moved over into the block text string is divisible by five. So I can say if blocked text, mod by five, or in this case, I'm going to use the variable size that way. If I change that to be seven or four, whatever, it's still going to work equals zero. So that's checking to see is it divisible by size. Then I want to add a space before I do anything else. So like if there's already five characters in there, throw a spacing. This is 10 characters in there, throw a spacing. And then after that, after it's decided whether or not it's going to add a space, then I want to just move over whatever character is assigned to the variable character. So again, to kind of go over what the for loop is doing is it's going to pull a character out of the string text. It's going to look at the string block text and decide, is it time for me to introduce a space there or not? If it is, it will. And if it's not, it won't. And then regardless of that decision, it's going to just move that character. It's going to copy it over into the block text string. It's going to do that for every single letter in text. Now we're going to see that this code actually will not work, not at least the way that we intended to. So let's just take a look and see what this will do and see how we might be able to fix it. Okay, so let's take our kind of standard. Hello, world string, and let's see what it does here in a perfect world. This is going to work. We're going to have hello as one block and world as a second block. But let's see what happens. We can see that that is not happening. And there's a few reasons for that. The first is you can see that there's a space before the age is kind of hard to tell because you can't really see spaces. But when you highlight it, you can see that it is in fact highlighting a space here. So it's introducing a space right off the bat, which is not what we want. But then it looks like it's counting the number of spaces when it's deciding is the length of the message divisible by five. And that's not really what we want to do. We want to kind of how many characters that aren't spaces are in that string and see if that quantity is divisible by five. So let's go back and see if we can fix that problem first. Let's go back and see instead of counting or counting of the length of the block text string as is, let's take out the spaces and replace them with an empty string. Remember, when we use the dot replace, that's not actually modifying the string block text, it's just going to pull up that string temporarily make that replacement for whatever operation we're currently doing. But it doesn't actually permanently change that string. So we're not we're not going to mess anything up here. And now what it's going to check to see is if it takes out all the spaces or whatever is left over divisible by five. And that sounds more like what we were intending to do. We don't want to count spaces and deciding is it time for me to introduce a new space. So let's rerun that code and see what that does. This is looking a little better. I don't think this is a little bit longer. Hello, world. Mr. Gibson is here. And we can see, yeah, that that's looking pretty good is blocking everything out in groups of five until it runs out of characters to use. And then the last block is for that looks perfect. It still has that leading space in front, though. And that might not seem like a big deal. But again, a lot of what we're trying to accomplish with our code is predictable inputs that give us predictable outputs. And if you're about to pass off this block text to something else and it's not expecting a space there, that might cause some issues. So you want to think about why is that happening? Let's go back up to our code. The very first time we enter the for loop, it's going to check is the length of the block text without any spaces in it divisible by whatever we set the size. So by default five. And that's going to be true the very first time we run it because that the very first time you run it blocks text has a length of zero. And that is divisible by five or seven or whatever number you put the size. It's always divisible by it. So the very first thing that it's going to do that block text string is introduce a space right off the bat. That's where this space is coming into play. So we can get around that. I think the easiest way to get around that is just introduce a second condition in our if statement. We don't want it to do that if it's the length of the string is zero. Every other time that seems to be working fine. But we want to just make sure that if the length of the block text without spaces is divisible by our size variable and the length of the block text is not equal to zero. Then go ahead and add the space. So about both of these things to be true before we introduce a space. And since this highlighted one here, the length of the block text not equal to zero is not true the first time we run this. It won't introduce this space when we first start out and there's nothing currently in the block text string. So I'm going to rerun this. And now we can see all right is blocking things out correctly. There's no leading space that I can select over here. This is the way we want our output to be formatted. So that should do it here for our text block function. I'll just really quick verify that the optional keyword argument does work if I want to make for. I can block it in groups of four if I want to block it in groups of seven. That all works. We've got a lot of functionality here on this short little function. So I would encourage you to add this to your toolkit as well. So you've got this readily available whenever you need it. This will be helpful whenever we're creating ciphertext that we need to space out the correct way. Thank you for watching and we'll catch you on the next one.


Proudly we hail! From New York City where the American stage begins, here is another program with a cast of outstanding players. Public service time has been made available by this station for your Army and your Air Force to bring you this story as Proudly we hail the aircraft observer of the United States Air Force. Our story today is entitled Fly By Night. This is the story of a radar observer and his girl. A radar observer is the second man in a two-place F-94 all-weather jet fighter plane. And the girl? Well, she's a girl, a nice girl. Our first air curtain will rise in just a moment. But first, learn to fly. Serve your country in the air. Be an aviation cadet. You'll get the finest aviation training in the world from the United States Air Force if you're accepted. To qualify, you must be single, be between 19 and 26 and a half years old, and be otherwise qualified. If you can meet the test, join the world's best. Join the aviation cadets. When you successfully complete your training, you'll win your wings and become a commissioned officer. For complete details, visit your local recruiting station or your nearest Air Force base. Make flying your future. And now your Army and your Air Force present the Proudly we hail production Fly By Night. My name is Edwards Jim Edwards. I was given the job of writing an article for my magazine about the seeing eyes of our modern aircraft, the aircraft observer of the United States Air Force. To gather first-hand information for my story, I was sent to Connolly Air Force Base in Texas. The first time I saw Paul Walker, he was looking at a radar screen in the B-25, a two-engine Mitchell bomber high in the Texas sky. The plane we were in was being used as a trainer. Forward, it was like any B-25, but aft in the fuselage was different. The rear section was separated from the rest by light-proof curtains. I asked Walker's instructor about it. It's like teaching a pilot instrument flying, Mr. Edwards. Only the instruments aren't for the pilot. Back here, unable to see out as the student, a fledgling aircraft observer, he has a radar screen in front of it. Now he's trying to locate by radar and keep on the trail of a target plane, just as though the target plane is an enemy aircraft in this B-25, a speedy little jet fighter. Well, that one there, he seems to be talking to himself. Well, he's telling the pilot what to do. He's at the number one screen, and he's telling the pilot how to fly so as to keep the target in view. Now, the pilot follows his instructions as though he can't see at all and is completely dependent on the observer. Well, from which student? There's another man at another screen. Well, each student and his turn. Now, each one becomes the observer for one pass at the target plane. Each one works a different problem, so to speak. While one is flying the pilot, there's another student over there watching on a duplicate screen listening to the instructions and another sitting by the pilot hearing the same instructions, but able to see the target visually and see the pilot's maneuvers as a result of the instructions from the student at the screen. Oh, excuse me. I have to go now to set up another problem. May I watch? Sure, sure. Come along. Uh, Mr. Walker, it's your turn now. Yes, sir. This is Jim Edwards, Paul Walker. I am. Mr. Edwards here wants to find out what we're doing, what you do under the hood there. I'm not sure myself sometimes. I sit there looking into my scope, looking for the little light-colored spot or blip that means the target plane. I turn this and that, these knobs here to train the plane's radar antenna on the target to try to keep it in sight within its beam. How does that work? Well, it swings the antenna around from one side to the other up and down, indicating something you can't see in the night by swinging around a spotlight. When you don't know whether the thing you're looking for is higher than you are lower to the right or left in front of you or behind, then, well, these tune the radar unit and make adjustments. Looks like enough to keep you busy. Oh, it's not so much. As long as you keep your head and have four hands. I see what you mean about four hands, but what do you mean keep your head? Well, you have to talk to the pilot and keep talking to him, telling him which way to go. At the same time, you have to manipulate these controls to keep the target plane on the screen and be able to figure out its course and rate of speed and your own. You have to get so used to these things that they all become automatic. Well, what's that over there? Well, that's the panic button. If I should get too confused, I press that and the pilot knows I'm in trouble and the instructor will take over. Does that happen often? Well, honestly, I don't know. I haven't had to use it yet, but I guess I've been lucky. Now, you say you look for a target plane. Is it trying to get away or does it stay on course and you try to intercept it? Well, Bogey, we call the target plane Bogey, tries to cause us trouble. The first few trials we make are on straight intercepts. Bogey is flying on a certain course and we're informed of it and are supposed to guide the plane to a point where we can go after it. Well, that sounds like a mathematical problem. Yes, it is, in a sense. That's without evasive movement. But then on later training trips like this one, Bogey is not only trying to get away, but my instructor here is talking to him by radio, telling him what to do to stay off my screen. It's moving, you're moving. You know something's there, you don't know where. Bogey can be anywhere. So your first job is to catch the target plane with your radar. Yes, sir, that's right. First I have to get Bogey within the radar beam, then I have to hold it there and be able to figure its course and speed in conjunction with ours. Then I have to instruct the pilot in such a way so that he can fly us to within shooting range. Not only that, but come up to it in such a way that we can get in the first shots. All right, Mr. Walker, you're on. You take over now. I can see the young man's expression change. His lean and tense face showed his concentration. He was sitting up straight on the metal-backed seat, bundled to the ears and flight gear and parachute. He was wearing an Air Force helmet with a visor on it that he pushed back so he could look directly into his radar screen. All I could see was a large black box like a studio photographer's camera. Extending six or eight inches from the box was a smaller section that was built and padded so he could put his face against it and look under the screen without any outside light to cause trouble. Look for the hope to find a little oblong spot of light. A blip that indicates bogey. Radar observer walk at a pilot. No joy, steady on course. Oops, I think... No. Port 20 degrees. 10 degrees up. There. Contact. Maintain course. Bogey 25 degrees port. Range 4500. 10 degrees above. Closing at 25 miles an hour. The instructor had led me to expect that. Mr. Walker had located the target plane on his scope. He was telling the pilot that Bogey was ahead of him 25 degrees to the left, 10 degrees higher, some 4500 yards away, and was being overtaken at the rate of 25 miles an hour. All this he had to figure from the changing position of the little blob of light as it moved past the graduated lines on his screen. Then, just as everything seemed to be going well, he had trouble. Behind him the instructor flashed me a grin that said, that was too easy, I'm making it tough for him. Hart starboard. Nose down 10 degrees. 20. Hart starboard, he's off. No arms. Hart starboard again. I've lost it. Bogey's drifted right off the screen. Mr. Walker, unless you give the pilot some different instructions soon, we'll be digging a hole in the ground. That was a part of the training of Paul Walker of Ellsworth, Maine, at Conley Air Force Base outside of Waco, Texas. That was a fraction of the business part. Then when the studying was finished... Beautiful ceremony. I was so proud of you, Paul. Now kindly address me with the respect of which I'm entitled. Lieutenant Walker, if you please. Very well, second Lieutenant Walker. All right, I know what I'm like. Certainly took an act of Congress to make me an officer and a gentleman. Oh, a fine thing to say about you. I thought you were a gentleman the minute I saw you. You know, I was looking at you and wondering who you were and how I could get to meet you. So you came over and introduced yourself? Mm-hmm. Paul, what would have happened if I hadn't had that invitation from Ann to come visit her? Well, you have to believe in fate, Sally. The way I do when I think of you. I knew the minute I saw you that you were the girl for me. If you hadn't come here to visit your sister, I'd have met you somewhere somehow.  Let's go outside for a little while. It is nice out here. I was just... visiting here for a little while. Ann wanted me to stay longer and I wasn't planning to till I met you. I'll always be grateful to her. So will I. I don't know what I would have done if I'd met you and then had to leave.  I didn't realize how much it could mean until I met you. It won't be too long. I'll be able to see you on weekend. You certainly will. I have a leave coming to me now that I've finished my aviation cadet training before I report to my new assignment. Mother thinks it's scandalous that I stayed down here so long. They're anxious to see you in person. I hate to think what you must have written to them about me then. What could I write? Nothing but the truth.  Is it getting your wings today that makes you make such pretty speech? You know, I should be the happiest guy in the world tonight and maybe I am. I'm in love with the nicest girl in the world and she's in love with me. And so in love. And today I won my commission in my wings. I've got you and I'm a full-fledged aircraft observer in the United States Air Force. Well, I hope it's in that order. But I sometimes wonder if you're not more in love with the Air Force than you are with me. Ah, you don't mean that. What are you doing? If this is what you want to do, that's what I want you to do. I'm going to get married as soon as we can. I'll be getting a good salary. I won't be spending much. I can save up enough so... so that we can get married. Oh, darling. Oh, everyone's leaving. Is it over so soon? You want to go? No. No, not right away. Oh, I don't ever want to leave you, darling. This is the aircraft observer, Paul Walker. Lieutenant Walker. And our first-class flying radar man is assigned to Everest Air Force Base just a few minutes as the jet flies from New York City. Lieutenant Walker is part of ADC's the Air Defense Command's 18th All-Weather Squadron. Flying the speedy, sturdy, two-place F-94 jet fighters. Lieutenant Walker's pilot is Captain Brown, Ed Brown from Timor in Iowa. All right, the rest of mine. Two jumps left. My two diamonds go on dummy's clubs. Okay, partner, we made it. Now, let's see, that's game and rubber. Oh, did we take them that time? Kid, I'll say this much for you. You've got the elements of a good bridge player. You know when to make a noise and when to keep quiet. Well, thank you, kind sir, but what would you have said if I hadn't had those four clubs and we'd gone down? Oh, what would I have said? I think I'll sit out. This time I had some maps here. I've been going over. I want to put them in our plane. I want to have to look for them if I need them. Hey, Ned, come on over and sit in for me a couple of hands, will you? I'm bequeathing you a partner who is almost as good a bridge player as he thinks he is, but only almost. How's he doing here, a new radar man? All right, good kid. Has that native New England caution makes him a good bridge player? Yeah, we can see that. How do you find him in the air? As I was saying before being so rudely interrupted, there's something about him that's going to make him a really fine aircraft observer. Never gets rattled. All he needs is experience. That's something you'll get here all right. Yeah, and as long as I'm his pilot, he'll get it in bad weather. Nice night like this, we might as well be in bed. We'll never get a call. If that squawk box on the wall opens its cap, it'll be buckshot 12 or 17 or some number. Any number except buckshot 23. But wait until you get a knife when the birds will walk. Then that box doesn't know any other number, but buckshot 23. That's a hard life you lead round, and we all sympathize with you deeply.  I held better cards when the kid was my partner. Meaning no offense, Ned. He's sort of an eager beaver, that walker, isn't he? Going off now to make sure he puts the maps in his plane. That's the answers, that's all. One no trump. He's new here. Just finished his training a few weeks ago. He wants to make sure there's no mistakes. I said one no trump, and I don't blame him. Well, he's right. But none of us are ever exactly careless. Pass. Scramble. Buckshot 19. Scramble. Vector 310. Angels 25. Call Baldy on easy. Oh, buckshot 19. Not for us, after all. Oh. You got back here in record time. I heard the gong. I was just coming in the door in case it was for us. I was already at the plane. I know. You wouldn't go five steps from here while on duty. Of course. To me, we don't get called very often.  We get our fair share. Couldn't happen to us in a nice, clear night like this, though. There they go. You are listening to the proudly-behaved production Fly by Night. We'll return in just a moment for the second act. How many of you young fellows go down to your nearest city airport on a Sunday afternoon and watch the planes come in and take off? When you see the planes gliding down at the airports, do you marvel at the skill of the pilots who fly them? And when you see the planes take off and disappear into the horizon, do you watch them out of sight wishing you were there at the controls? There's no more need for any of that wishful thinking. If you've got what it takes to be an aviation cadet in the United States Air Force, you, too, can fly the big silver birds. You have to be young enough and smart enough and well enough if you want to qualify as an aviation cadet. Only the best are accepted. Your local recruiting station or nearest Air Force base can give you all the information. You are listening to Proudly We Hail, and now we present the second act of Fly by Night. Lieutenant Paul Walker, a flying radar man has something on his mind. Besides taking off in his old weather jet fighter plane with his pilot Captain Ed Brown, after an identified plane that gets near Everest Air Force Base not too far from New York City. I'm going to be reading and rereading a letter. Captain Brown has gotten a letter, too, but it didn't take him so long to read it. Well, don't look so smug. Other guys have gotten letters from their girls before. Oh, no, not from Sally, not like this. Uh, Dames. Huh? What's the matter? Emily, my girl, just like all women. When you count on them, they're somewhere else. Oh? Yes. Emily will be in Charleston recuperating from an attack of an influenza. I'm terribly sorry, dear. I was so looking forward to seeing you again. Oh, gee, that's tough, Ed. I've told Sally we'll have written her anyway so much about you, and I know she wanted to meet you. Maybe Sally knows someone. Blind dates? Boy, if you knew the flat tires I've taken out on blind dates. Well, I can ask Sally when she gets here, and even if she doesn't know anyone, and you can't think of a girl you'd like to take, you'll come along with us anyway. I want you to meet Sally, and we'll have fun. Oh, sure, I'd be as welcome as a flame out on a takeoff. Thanks. Maybe I'll take you up on it at that. And maybe Sally will know someone. All set? I told Mother I'd be staying with Sally at the Biltmore, and she said it was all right. Oh, it's all arranged now. I'll see you get delivered home. Safe and sound. Oh, don't be too sure. Why, Captain Brown? Look, I don't mean to sound silly. I know you're fliers, but I get all confused. What do you two men do? Well, he's my chauffeur.  You have to give detailed instructions, too. He just rides along on my plane to give it ballast. You see, if it didn't have someone else in it, it's so fast and powerful, it might fly right out from under me. Oh, come now. I thought you were with the ballast. Oh. Touché. Well, you see, we're ADC. That's Air Defense Command. Now, all around at key spots are big radar setups. I don't know how wonderful it is to be with you again. I feel as though I'm dreaming. I wanted to have you in my arms for so long that now I can't believe it's true. I don't even want to think. I just want this to go on forever. Well, maybe it can soon. We won't have to wait much longer. I figure I've got a leave coming to me in about two months. I think that'd be a fine time to get married. Any time would be a fine time. As long as it's to you. It's a month later now. Walker and Brown are back being buckshot 23 of the 18th all-weather squadron guarding the air approaches to New York and Washington. They're on duty in the ready shack, strapped in their parachutes, wearing G-suits, all the paraphernalia necessary for high altitude flying. Their minds are on their work. The girl's forgotten. Hey, Ed, you gonna get in this bridge game or not? Uh, a little later. Oh, don't bother him, boys. He's writing a letter. And just a few weeks ago, he was teasing me. If this weather keeps up, some poor mailman is gonna get awful wet delivering it. Anybody been out lately? Yeah, I have.  Wind a small gale. Scramble buckshot 23. Scramble. Vector 090. Angels 2-0. Call Baldy on Echo. That's us. Come along, Ed. Scramble buckshot 23. Scramble. Vector 090. There goes the bridge game. There goes an F-94 carrying Lieutenant Walker and Captain Brown. As soon as a squawk box called their signal, buckshot 23, they ran from the ready shack into the hangar where their plane was waiting. The hangar doors opened wide. The whole front of the hangar was lifting itself up and back. The speedy, heavily armed jet moved quickly from the hangar to a main runway less than 100 yards away. And Captain Brown began to pour on the coal, rocketing the plane down the runway. The jet takes off into the dark. It's after Burner accommits tail in the night. The whole business of getting into the air took practically no time. These men are part of the air defense command. They have to be ready to move immediately.  Okay, Paul. Okay, Paul. Okay, Paul. Okay, Paul. Okay, Paul. Okay, Paul. Paul. Right back here. I'm calling GCI. Baldi, this is Buckshot 23 on Echo. How do you read me? Buckshot 23, this is Baldi. Read you loud and clear. Buckshot 23, Vector 090. Angels 1. Climbing to Angels 3-0. Roger, Buckshot 23. Bogey at your 10 o'clock. Still 20 angels. Degree, Starbert. Three degrees below range 20,000 yards. Turn, Starbert. Hard, Starbert.  Still three below, steady on course. Closing at 60. Bogey dead ahead. Roger, Paul. Starbert easy. Too far. Five degrees port, he's off. That's it. Nose down two degrees. Level. Range 5,000, closing at 60. Range 4,000, port easy. Now that's enough. Chop off 40. 3,000 yards. Less. Bogey three degrees port. 2,500 yards. Take over, it is yours. Keep talking, no joy. Bogey now five degrees port. Level. Turn port easy. Bogey now four degrees. Three. Two. One, dead ahead. Got it. Right up. Multi-engine, installation. Making visual check, U-2. Overseas Airlines Super Constellation, off course. Reporting at the Wally. Wally, this is Buckshot 2-3. Check Bogey, O-A. Super County, Angels 1-5. Course, 1-9-5. Speed, 3-2-0. Roger, Buckshot 2-3. Overseas Airlines Flight 4-8 un-reported at checkpoint. Off course. Come in, Buckshot 2-3. Contact Everest, GCA on Cocoa when approaching field. We'd better check in with our report. I wonder what happened to that pilot? Well, you know how it works. When they leave Shannon or wherever they come from, they get instructions how and where to identify themselves when they get within radar range of the U.S. It's a wild night. He must have been blown way off his course and didn't check in and went in where he could. Yeah, and what was it Colonel Mattson said? Anyone who doesn't identify at a checkpoint is the enemy until proven friendly. That's it, you never can tell. Boy, it's a nasty night down here. You know what, I forgot all about how mean the weather was when we got up there? Got over the clouds and there was that big moon. Yeah, I know.  Completely different world. And all the while you've been away, it wasn't very long, but we went a couple of hundred miles and all that time, no one except Baldy and the boys here at the base knew we were gone. That's right. Even the crew with that airliner didn't know we'd come up and we're camping on the tail. Just in case, they turned out to be unfriendly. They didn't know? And all of the people like Sally and my folks sleeping peacefully down here didn't know it either. Didn't even know we were in the air. They were sleeping better because we were. Gives you funny feeling, doesn't it? Oh, come on, you're getting positively poetic. Three diamonds. Oh, there you are. Home of the heroes. Hey, I gotta stop in a few minutes. Want to take my hand, Ed? Don't mind if I do. Paul? No, I'll be back in a minute. I'd written a letter but hadn't sealed it. I'd like to go look it over. Well, here you are, partner. Two aces and a Queen Jack ten. Don't say I didn't treat you right. Hey, how's Lieutenant Walker doing now? You said a while back all he needed was experience. He can give any of you boys cards and spades right now and beat you. And he's still improving. Right now, I'd say... I'd say he's the best darn radar operator in the Air Force. Which is a lucky break as he's with the best darn pilot. Here, here. Well, he is. And I'll prove it to anyone who doesn't believe me. Now, if you've given your poor partner enough trouble, I'll take over your hand and try to pull you out. So, dear, I can't see any reason why we should wait any longer. Colonel Madsen said he thought I could figure on my leave in about two weeks. So I'll be out to pick you up. And it's a good thing it's so soon. Because I don't think I could wait any longer. Well, it just about does it. I'd better seal it and mail it now before I get to thinking about it and try to write it better. Well, that's my story. It'll appear in the latest issue of my magazine. It'll be on your newsstand next month. As you can guess, it's about a group of men who never sleep, the officers and men of the Air Defense Command, and particularly the radar observers, the flying radar men who guide the defense planes to their target, who are in readiness 24 hours a day to see that anyone who approaches our borders is on a friendly mission. They are truly the Minutemen of this jet and rocket and atomic age. By the way, there's a post script to my story. You won't read it in the text of my article, Lieutenant Paul Walker and his girl, Sally, were married last Sunday. How would you like to be a kingpin on the aircrew of the United States Air Force plane? That's the navigator. He's an aircraft observer, a commissioned officer, and he gets there by enlisting in the aviation cadets. It's a great life, but only men young in spirit and years can fill this exacting job. If you can qualify, your advanced training by the Air Force will turn you into a first-class navigator. Then you'll be a kingpin on the aircraft team. You'll be equipped with the finest navigation tools known to aerial science. See what your chances are for joining the aviation cadets of the United States Air Force. Full details are available at your nearest recruiting station or Air Force base. This has been another program on Proudly We Hail, presented transcribed in cooperation with this station. Proudly We Hail is produced by the Recruiting Publicity Center for the United States Army and the United States Air Force Recruiting Service. This is Kenneth Banghart speaking and inviting you to tune in the same station next week for another interesting story on Proudly We Hail.


I'm a soil scientist based at Lincoln University and I'm fascinated by the movement of carbon dioxide into and out of soils in the dry valleys of Antarctica. The dry valleys are a fantastic part of Antarctica as you know most of the continents covered by ice but we have these small parts of the landscape that are essentially ice free. In these ice free areas there are incredible microorganisms that exist basically at the limit of life. It's really cold, it's really dry, it's windy, it's salty, all of those things that make it difficult for life to exist. So what we're looking at is putting in long term monitoring stations to look at how the activity of these microorganisms changes over time. And by doing that we can then compare those sorts of records with records that we get from other locations and basically set up some way of predicting how these communities might respond to future climate change. What I've discovered is that there are natural physical processes going on in these soils that also produce carbon dioxide.  But at the same time in these dry valley soils which have a very unusual chemistry we have a natural physical process that also produces CO2. What we're trying to do in the system is to disentangle the biologically produced CO2 from the non biologically produced CO2 so that we can get a true signal of how active these communities really are.


Γεια σας και добρία ilk. Γή gent i'm going to show you a really fun technique, one of my favourites when it comes to embossing i'm going to showcase the technique by using this lovely full stencil, this is from the latest release by Waffle Flower and it's full of leaves. Perfect for this season. However it would work with any stencil that you have at home. For my example today i'm working on watercolor paper just because i know that the stress oxides do blend beautiful on watercolor paper Επίσης, εγώ αρέσει το τέκτυρο και αυτό το τέκτυρο για ένα φόλ καρδί είναι καλύτερο, νομίζω όχι, μπορείς να κάνεις την ίδια ίδια τέκνιξη σε ένα μικρό πίσω της πέμπυρας. Είμαι σκέφτητας το στενσίδι, από το σπίτι και μόνο από μόνο μέσα. Αυτό είναι πολύ σημαντικό, θα δείτε why in a bit. Είμαι χρησιμοποιώντας ένας από τα τελευταία κόμπωσης όταν έρθει στον φόλ καρδί και αυτά είναι τα διστρέσεις μου οξίδες στο σπίτι και το καρδίκτο κόμπωσης. Είμαι μπροσφημένος απλώντας my two shades of orange there και φυσικά depending on the stencil that you are working with you can throw in the mix even more colors and let's lift the stencil so you can see what we have up to now Already gorgeous and you can use that as a background on a card however let's take it a step further i'm going to throw in the color mix a little bit of dark brown i'm using ground espresso here and i'm going to add some splashes over the stencil this way i make sure that they're going to stay directly on top of the leaves every time i make a step i lift the stencil so that i can see what i have up to now and now this is where i decided that i wanted to throw in a little bit more of that brown so with a very fine brush i'm adding a touch of brown on all of these leaves just a little bit on one side we'll do the trick you will see that when i lift it it's going to give a completely different look i think that the beauty of every card is always in the details and again i'm going to leave the stencil so you can see what to have up to now this would work as a background as it is just stick a sentiment or to where you have a lovely full card but there is always one more step that can take your card to another level this time i'm going to splashes with gold watercolor now these splashes fall only on the opening so only where the leaves are i'm going to leave the stencil and hopefully you will see all that shine that i got from those splashes and now let's clean the stencil without removing it from the paper my tape works as a hinge so i can easily clean it up without making a mess on my background it's really important in this step to clean up the stencil since i'm going to move on and work with a versa marking and i don't want to make any smudges or contaminate my ink pad and once i'm sure that the stencil is completely clean front and back it's going to fall exactly where it was in the beginning and before i move on and do my embossed resist this is where my mixed media side kicks in i just wanted to do some stamping through the stencil so i'm using just a text stamp that i had in my stash again using the same distressed oxide brown ink that's ground espresso and i'm stamping through the openings the text which is going to fall only on some of the leaves i didn't do a perfect stamping i just wanted some stamping here and there just for some added interest again you can stop here it looks stunning but let's go ahead and do some embossed resist now for that you are going to use your versa marking you can either go all over the stencil directly with your ink pad either you are using the smaller or the bigger one but there is a chance to contaminate your ink pad if you want to keep it nice and clean you can use the re-in so here i have my versa marker ink and i'm going to apply a little bit of that on the foam of my blending tool of course you don't have to work with versa mark ink any embossing ink that you have at home will work for this technique i'm going to make sure that this is nice and wet and then i will go over all of the leaves everywhere where i have an opening i can make sure that these are all nice and wet if i lift and tilt it to catch the light and let's check the foam and see if it was at all contaminated and the truth is that it stayed quite clean now this is where i have covered everything i'm going to catch the light and hopefully you will see that every area is shiny this means that i do have versa marker everywhere and it's time to apply clear embossing powder the embossing powder is going to stay only where the leaves are and it's going to block them it's going to protect them and make them resistable on any other ink blending that i'm going to do later on on top it's a really fun technique it gives a color block effect and i absolutely love it it's so much fun to play with embossing powder after all the added bonus is that you will end up with shiny leaves which are going to stand up even more and it's always so satisfying to see the embossing powder melt and turn those leaves shiny heat embossed technique was what fascinated me when i started with card making and it never gets old and i'm going to take a moment here and just appreciate how beautiful it is i wanted to cover up the background with brown but i absolutely love it as it is however since that was the plan from the beginning i'm going to go ahead and do that i'm starting with vintage photo just to apply a light brown all over the background i'm going over the leaves i don't mind if i cover them up they are going to resist the ink and once i cover it up completely i can go ahead with a cloth and just wipe them off before i move on to a darker shade i'm going to bring my trimmer and cut it and this will end up being four by five and one quarter and then to help those leaves pop even more i'm going to go all around with an even darker shade of brown this time i'm using ground espresso i did go all the way to the edge and i let that left the center a little bit lighter and i'm going to finish it up with some black shoot all the way to the edges the darker the color of the background the more the color of your design is going to pop now i'm going to bring in a clean cloth and i'm going over the leaves make sure that i remove any excess ink that stayed on top and here is what i have up to now absolutely stunning that embossing ink trapped even those splashes of gold watercolor and it is really stunning in real life all you have to do with a card like this one is to add a sentiment on top for that i did use an alphabet die set by waffle flower to cut out those long letters and i did cut them out the outline out of brown cardstock that matches the color of my background and then for the thin letters i did use gold glitter cardstock i'm sticking one on top of the other for that i'm using my berry art glue just because it has a very fine tip and if it oozes out from behind it's not going to show it's going to disappear completely and just because i left a mention i'm using those fine strips of foam tape at the back i'm just taking the time to do that or on the back of all the letters so that i can pop them on my card now to make sure that these are nicely leveled and lined up i'm just using a t-ruler i'm spelling the word fall and to complete my sentiment i did found one of the sticker sentiments by team halls this is from a booklet and i'm just going to stick it underneath that says there is always something to be thankful for i'm finishing off my card by adding a few gems these are in copper color but the truth is that this is already a very shiny card and really beautiful in real life so you really don't have to embellish it even more i placed this panel on a chocolate brown card base that's four and a quarter by five and a half and you can see here some close-up photos a post resist is a fun technique and gives amazing results and i hope that this video was fun and that you got inspired to try it out yourself this video is part of a blog hope as we celebrate the latest release by waffle flower make sure to visit my blog you will find the link down below where you can find out how you can win prizes thank you all so much for joining me today you will find a list of everything i used down below i hope you all have a lovely day and i'll see you all on your day with a new art journal layout


It's 1907 and Albert Einstein has just had what he would later describe as the happiest thought of his life. What do you suppose it was? Maybe a complicated mathematical expression? Nope, it was this. If a person falls freely, he will not feel his own weight. Yup, that's it. Because as we saw in video three of this series, that insight allowed him to recognize the physical equivalence between floating and falling frames of reference. At least if the frame is very small. Since inertial reference frames are described by special relativity, which we developed in videos one and two, this insight allowed him to apply special relativity in the presence of a gravitational field. But there's that very small caveat. What's up with that? Gravitational acceleration falls off as you get further from an attracting body. Yes, you can enclose two widely separated objects in their own individual falling frames, but neither of those frames can be extended to, quote, fit both objects and still look like a single inertial reference frame. Even if two objects are at the same height, if they fall from different directions, there is no single falling frame that will, quote, fit both. In general relativity, this fact is explained by saying, space time is curved. To understand why, let's say you operate flat land industries that provide surveying surfaces for the inhabitants of flat land. You have a standard recipe for drawing a triangle. Pick three points. Between each pair of points, stretch a rope. The taut rope will follow the shortest distance between the two points, and that will be a straight line. As a check, if you measure the three resulting angles in some of them, you should always get 180 degrees. Now play along with me and assume that if you're on the ground, you can only view a very small area at a given time. You don't have the bird's eye view that we're showing here. You complete a triangle job and measure angles of 57, 60, and 63 degrees, which indeed some do 180. Now you happen to know someone who has a new fangled flying machine who agrees to take airborne pictures for you. She reports back that indeed you drew a triangle, and from directly above it has the claimed angles. However, if she flies around and looks at the same object from different points of view, the angles change, although the object remains a triangle with straight sides, and the angles still sum to 180 degrees. You get a call for triangle services from folks in far away Kervland.  So you call in your flying friend to see what went wrong. She tells you that you connected the points with some kind of curves, not straight lines. She finds out that she can fly around and find a point of view in which any given side appears as a straight line, but she can't find a single point of view from which all three sides appear as lines at the same time. Of course what's happened is that you're trying to do geometry on a curved surface. On such a surface straight lines may not even exist, but we still have the idea of the shortest path between two points, and we call such a path a geodesic. Their shape can meander around as they try to avoid hilltops and the like, and the normal rules of Euclidean geometry break down. For example, a circle is a set of all points equidistant from a central point, and the circumference is supposed to be pi times the diameter. But on a curved surface, the circumference can be less than this. Look that from the appropriate point of view, we can see why. The curve that serves as the diameter is curved, and so has a greater length than what the diameter would be on a flat surface. We can also get circles with a circumference greater than pi times the diameter. Yes, this is a circle. Every point on this curve is at the same distance from a central point. Same distance in the sense of a geodesic. Since the surface curves both up and down, the circle has to undulate, causing the circumference to be larger than pi times d. Why does Euclidean geometry break down on a curved surface? It has nothing to do with how we designate position, that is our coordinate systems. On a flat surface, we can use different types of coordinate systems, but straight lines still exist. They're just described differently. The problem is something intrinsic to the surface. No matter how we designate position, in general, on a curved surface, we cannot form things like normal triangles and squares. Now for small enough patches on the curved surface, we can attach more or less flat pieces of graph paper, and Euclidean geometry will work on those patches. But if you try to attach a large square of graph paper, you'll be able to get one, two, even three of the edges pasted to the curved surface, but not the entire sheet. You end up having to cut the sheet and manipulate the pieces, and in doing so, you're going to alter the geometric properties of the graph paper. Alternately, you could imagine the graph paper made out of rubber, and then you have to stretch it in weird ways. In either case, no intact graph paper equals no Euclidean geometry. What Einstein came to realize is that inertial reference frames are like the flat graph paper, and special relativity is like Euclidean geometry. You can map small individual pieces of inertial frames, that is freely falling frames, to various regions of space-time, and special relativity will work in those pieces. But the fact that you can't map one big inertial reference frame to all of space-time means that space-time itself must be curved by massive objects. What remained was to work out the details. Now there were a lot of details, and true, those details involved a lot of math. For starters, physics involves not just space, but also time. So that's four dimensions of space-time. And what exactly is a four-dimensional space-time surface? What limits does nature put on its curvature, and so on? But keep in mind that math was just the crank that needed to be turned to produce specific results. The physical insight, which was the true genius of Einstein, was not primarily about math. In fact, a mathematician named David Hilbert presented the full equations of general relativity before Einstein did. So why are they named after Einstein and not Hilbert? As brilliant as Hilbert was, he was just turning the admittedly quite complicated mathematical crank needed to express Einstein's insight. As he himself said, every boy in the streets of Goodenken understands more about four-dimensional geometry than Einstein. And in spite of that, Einstein did the work and not the mathematicians.