1 00:00:00,000 --> 00:00:10,577 >> [MUSIC PLAYING] 2 00:00:10,577 --> 00:00:11,410 RAMON: Hello, world. 3 00:00:11,410 --> 00:00:12,610 This is CS50 Live. 4 00:00:12,610 --> 00:00:14,940 I'm Ramon Galvan, filling in today for David-- 5 00:00:14,940 --> 00:00:16,390 >> DAVID: Who's lost his voice. 6 00:00:16,390 --> 00:00:18,970 >> RAMON: Today, he'll be the Andy Richter to my Conan O'Brien. 7 00:00:18,970 --> 00:00:24,220 As we tour Harvard campus today, blow glass today. 8 00:00:24,220 --> 00:00:25,540 But first-- 9 00:00:25,540 --> 00:00:28,850 >> DAVID: And so, so much more in today's episode. 10 00:00:28,850 --> 00:00:33,400 But first, a look at a recent field trip. 11 00:00:33,400 --> 00:00:36,610 >> RAMON: Recently, this past weekend, we took a trip to St. Louis 12 00:00:36,610 --> 00:00:40,220 to be visit LaunchCode for the first ever CS50 Hackathon 13 00:00:40,220 --> 00:00:41,740 outside of Cambridge. 14 00:00:41,740 --> 00:00:45,100 And our own Shelley Westover has put together a little scissor reel 15 00:00:45,100 --> 00:00:46,310 to show you what happened. 16 00:00:46,310 --> 00:00:47,780 >> DAVID: Let's take a look. 17 00:00:47,780 --> 00:00:54,790 >> SPEAKER 1: So I'm here to announce today that David Mayo and a team of 12 18 00:00:54,790 --> 00:00:58,072 educators from Harvard University are coming 19 00:00:58,072 --> 00:01:02,590 to St. Louis, Missouri on March 28. 20 00:01:02,590 --> 00:01:06,100 >> DAVID: We are so pleased to announce the first ever CS50 Hackathon, that 21 00:01:06,100 --> 00:01:08,936 will be going on the road to St. Louis. 22 00:01:08,936 --> 00:01:12,728 >> [MUSIC - AMERICAN AUTHORS, "BEST DAY OF MY LIFE"] 23 00:01:12,728 --> 00:01:47,336 24 00:01:47,336 --> 00:01:50,822 >> SPEAKER 2: Woah, that was a lot faster than I expected. 25 00:01:50,822 --> 00:02:04,497 26 00:02:04,497 --> 00:02:06,038 SPEAKER 3: Shelley's driving the bus. 27 00:02:06,038 --> 00:02:10,529 28 00:02:10,529 --> 00:02:12,026 Oh, super wet. 29 00:02:12,026 --> 00:02:13,064 Wait. 30 00:02:13,064 --> 00:02:13,730 Second thoughts. 31 00:02:13,730 --> 00:02:16,900 32 00:02:16,900 --> 00:02:17,570 I'm going. 33 00:02:17,570 --> 00:02:18,562 I'm not looking back. 34 00:02:18,562 --> 00:02:24,014 35 00:02:24,014 --> 00:02:24,514 Oh no! 36 00:02:24,514 --> 00:02:27,486 37 00:02:27,486 --> 00:02:27,986 Damn it! 38 00:02:27,986 --> 00:02:34,347 39 00:02:34,347 --> 00:02:34,930 It's all over. 40 00:02:34,930 --> 00:02:54,684 41 00:02:54,684 --> 00:02:57,100 DAVID: And what you all have been waiting for here tonight 42 00:02:57,100 --> 00:03:00,878 is our first ever on-the-road CS50 Hackathon. 43 00:03:00,878 --> 00:03:04,620 >> [CHEERS] 44 00:03:04,620 --> 00:03:08,970 [INAUDIBLE] put faces to the YouTube views, I guess. 45 00:03:08,970 --> 00:03:10,830 [LAUGHTER] 46 00:03:10,830 --> 00:03:24,004 47 00:03:24,004 --> 00:03:27,462 SPEAKER 4: And this is CS50, and this is LaunchCode STL. 48 00:03:27,462 --> 00:03:42,790 49 00:03:42,790 --> 00:03:46,460 DAVID: The ultimate goal is to get to at least midnight, 50 00:03:46,460 --> 00:03:48,376 at which some excellent donuts will be served. 51 00:03:48,376 --> 00:03:50,325 And we'll be here a bit longer after that, 52 00:03:50,325 --> 00:03:55,850 but you should be proud if you can make it all the way we to midnight tonight. 53 00:03:55,850 --> 00:03:58,210 >> SPEAKER 5: 200 or so people are here tonight, 54 00:03:58,210 --> 00:04:02,630 and we're all really excited to be a part of Harvard's CS50 55 00:04:02,630 --> 00:04:05,168 and have you part of our city. 56 00:04:05,168 --> 00:04:06,575 Glad to have you. 57 00:04:06,575 --> 00:04:10,729 58 00:04:10,729 --> 00:04:11,770 SPEAKER 2: End on a joke. 59 00:04:11,770 --> 00:04:14,020 SPEAKER 6: What's the first sign of a nosy pepper? 60 00:04:14,020 --> 00:04:15,273 It's jalapeno business. 61 00:04:15,273 --> 00:04:18,464 62 00:04:18,464 --> 00:04:19,339 SPEAKER 2: Hey, Chad. 63 00:04:19,339 --> 00:04:20,172 They don't love you. 64 00:04:20,172 --> 00:04:20,784 Sorry, bud. 65 00:04:20,784 --> 00:04:25,510 66 00:04:25,510 --> 00:04:27,859 >> RAMON: You may also recall from last time, code.org. 67 00:04:27,859 --> 00:04:29,650 A non-profit that has been getting everyone 68 00:04:29,650 --> 00:04:31,220 excited about computer science. 69 00:04:31,220 --> 00:04:36,530 And it turns out that founder Hadi Partovi was actually a former CS50 TF, 70 00:04:36,530 --> 00:04:38,300 and he wants to say hello. 71 00:04:38,300 --> 00:04:39,260 >> HADI: Hello, world. 72 00:04:39,260 --> 00:04:40,860 My name is Hadi Partovi. 73 00:04:40,860 --> 00:04:43,360 I run an organization called code.org. 74 00:04:43,360 --> 00:04:46,080 We're best known for our Hour of Code Campaign. 75 00:04:46,080 --> 00:04:49,110 That's something we launched for the first time last year in 2013, 76 00:04:49,110 --> 00:04:51,840 and the last three months the Hour of Code 77 00:04:51,840 --> 00:04:56,070 has already reached 30 million students, showing that computer science is 78 00:04:56,070 --> 00:04:59,200 something that is applicable and something that anybody can learn. 79 00:04:59,200 --> 00:05:02,960 It's useful whether you want to become a doctor, a lawyer, an astronaut, or even 80 00:05:02,960 --> 00:05:04,210 the president. 81 00:05:04,210 --> 00:05:07,510 >> And those of you who are learning it in CS50 today, 82 00:05:07,510 --> 00:05:10,280 you're learning things like how to write a for loop or repeat 83 00:05:10,280 --> 00:05:13,470 loop, an if-then statement, or how to program your own functions. 84 00:05:13,470 --> 00:05:15,790 These are concepts that anybody can learn, and are 85 00:05:15,790 --> 00:05:19,170 fundamental to how all of computing around us works. 86 00:05:19,170 --> 00:05:22,780 >> I myself was a CS50 TF when I first went to Harvard. 87 00:05:22,780 --> 00:05:25,390 So it's exciting for me to record this video for you all. 88 00:05:25,390 --> 00:05:27,020 So enjoy yourselves. 89 00:05:27,020 --> 00:05:29,390 This is CS50. 90 00:05:29,390 --> 00:05:33,250 >> RAMON: You may also know that Mark Zuckerberg, created the Facebook 91 00:05:33,250 --> 00:05:34,780 back in his college dorm room. 92 00:05:34,780 --> 00:05:38,110 This is how it originally looked like. 93 00:05:38,110 --> 00:05:41,700 Also, you may not know that the original URL was not 94 00:05:41,700 --> 00:05:43,950 the Facebook or Facebook.com. 95 00:05:43,950 --> 00:05:45,630 >> DAVID: No, rather, it was this one here. 96 00:05:45,630 --> 00:05:50,609 >> RAMON: Roam.175-29.student.harvard.edu. 97 00:05:50,609 --> 00:05:53,400 DAVID: Which was the host name of Mark's computer in his dorm room. 98 00:05:53,400 --> 00:05:56,720 And in fact, pictured here is Mark with Chris Hughes and Dustin Moskovitz, 99 00:05:56,720 --> 00:06:00,325 two of the students with whom he went on to found Facebook itself. 100 00:06:00,325 --> 00:06:04,640 Now, Mark comes back to campus from time to time, and in fact, in 2005, 101 00:06:04,640 --> 00:06:08,460 he visited CS50 with Professor Micheal D. Smith and gave a guest lecture. 102 00:06:08,460 --> 00:06:11,390 In fact, if you look really closely, you can see Mark down up front. 103 00:06:11,390 --> 00:06:13,650 But let's take a look at a clip. 104 00:06:13,650 --> 00:06:18,580 >> MARK: Wanting to look people up, I think, is kind of a core human desire. 105 00:06:18,580 --> 00:06:19,510 Right? 106 00:06:19,510 --> 00:06:22,330 I think that people just want to know stuff about other people. 107 00:06:22,330 --> 00:06:25,454 So I think that providing an interface where people could just 108 00:06:25,454 --> 00:06:27,870 type in someone's name and get some information about them 109 00:06:27,870 --> 00:06:30,070 is generally a pretty useful thing. 110 00:06:30,070 --> 00:06:31,430 So growth has been pretty good. 111 00:06:31,430 --> 00:06:34,700 >> It was tough to figure out exactly how to gauge it, 112 00:06:34,700 --> 00:06:37,580 because when we did college, we opened it up at Harvard. 113 00:06:37,580 --> 00:06:40,080 Then we opened it up at a couple of colleges around Harvard. 114 00:06:40,080 --> 00:06:44,700 And the idea was always, we are really short on money and equipment, 115 00:06:44,700 --> 00:06:48,730 so while getting as little as possible, we want to maximize our growth. 116 00:06:48,730 --> 00:06:52,760 So we want to launch at the schools that we 117 00:06:52,760 --> 00:06:55,010 think are going to grow the quickest based on the fact 118 00:06:55,010 --> 00:06:57,468 that the people at those schools are going to have the most 119 00:06:57,468 --> 00:07:00,675 number of friends at the schools that we're already at. 120 00:07:00,675 --> 00:07:02,550 We took a different approach for high school, 121 00:07:02,550 --> 00:07:04,690 because we could just launch it everywhere at the same time. 122 00:07:04,690 --> 00:07:06,773 So we didn't really know how it was going to grow. 123 00:07:06,773 --> 00:07:11,310 I think it's growing at more than 5,000 people a day, which is pretty good. 124 00:07:11,310 --> 00:07:14,440 >> RAMON: For the full lecture, click on this link. 125 00:07:14,440 --> 00:07:16,050 >> DAVID: But not yet. 126 00:07:16,050 --> 00:07:19,610 You can get the full hour of Mark's talk there on the internet. 127 00:07:19,610 --> 00:07:22,680 >> RAMON: And now, let me introduce a current Harvard undergraduate, Sean, 128 00:07:22,680 --> 00:07:26,050 who wants to give you at tour of Harvard's campus. 129 00:07:26,050 --> 00:07:26,690 >> SEAN: Hi there. 130 00:07:26,690 --> 00:07:29,220 My name's Sean and I'll be your tour guide today. 131 00:07:29,220 --> 00:07:32,160 Originally hailing from New York City, I'm actually now a sophomore 132 00:07:32,160 --> 00:07:36,300 living Cabot house-- best house-- concentrating in neurobiology 133 00:07:36,300 --> 00:07:38,780 on the mind-brain behavior track, with a secondary 134 00:07:38,780 --> 00:07:42,430 in visual environmental studies on the film production track. 135 00:07:42,430 --> 00:07:45,804 Welcome to Harvard. 136 00:07:45,804 --> 00:07:46,470 >> Hi there. 137 00:07:46,470 --> 00:07:48,390 Welcome to the Science Center Plaza. 138 00:07:48,390 --> 00:07:52,150 It's said that over 10,000 people will come through these doors 139 00:07:52,150 --> 00:07:55,040 every single day, because there's a large number of things 140 00:07:55,040 --> 00:07:55,799 you can do in it. 141 00:07:55,799 --> 00:07:58,215 So one of the things I love about the Science Center Plaza 142 00:07:58,215 --> 00:08:01,780 is that during the summer, it becomes even more of a hub. 143 00:08:01,780 --> 00:08:04,080 Because we have all of these food trucks that 144 00:08:04,080 --> 00:08:06,530 line up from all different places in Boston. 145 00:08:06,530 --> 00:08:08,895 And in addition, we have crafts fairs, we 146 00:08:08,895 --> 00:08:12,200 have a weekly petting zoo, we have chessboards and bean bag chairs. 147 00:08:12,200 --> 00:08:15,470 So everyone loves to come out, whether to do homework or just chat, 148 00:08:15,470 --> 00:08:17,020 or just grab a bite to eat. 149 00:08:17,020 --> 00:08:19,790 >> So looking over here now, we have Memorial Hall Complex, 150 00:08:19,790 --> 00:08:22,400 which is exactly where CS50 lectures are held. 151 00:08:22,400 --> 00:08:26,030 So if you want to follow me to our next stop, we'll talk more about it there. 152 00:08:26,030 --> 00:08:29,177 >> So welcome to the inside of Memorial Hall Complex. 153 00:08:29,177 --> 00:08:31,510 Now, there's some really cool things about this building 154 00:08:31,510 --> 00:08:32,990 that you can see right here. 155 00:08:32,990 --> 00:08:36,309 First thing you notice is all of that stained glass. 156 00:08:36,309 --> 00:08:38,900 This building actually contains the second largest amount 157 00:08:38,900 --> 00:08:41,960 of secular stained glass in North America. 158 00:08:41,960 --> 00:08:42,980 Now why? 159 00:08:42,980 --> 00:08:46,550 This place was actually founded in 1870 as a war memorial, 160 00:08:46,550 --> 00:08:49,970 commemorating the lives lost of Harvard undergraduates who fought for the Union 161 00:08:49,970 --> 00:08:51,550 during the Civil War. 162 00:08:51,550 --> 00:08:54,630 >> Now, this building is filled with history. 163 00:08:54,630 --> 00:08:57,710 But it's also filled with a lot of cool other things. 164 00:08:57,710 --> 00:09:00,270 Some of you may recognize this building. 165 00:09:00,270 --> 00:09:03,700 It's actually the place where CS50 lectures take place. 166 00:09:03,700 --> 00:09:07,250 So this is actually just outside of Sanders Theatre, where 167 00:09:07,250 --> 00:09:10,020 David Malan actually gives his lectures. 168 00:09:10,020 --> 00:09:13,270 This space is really cool because it's actually three functions. 169 00:09:13,270 --> 00:09:15,010 >> First, there's Sanders Theater. 170 00:09:15,010 --> 00:09:18,700 But also, below us, there's a bunch of classrooms and rehearsal rooms. 171 00:09:18,700 --> 00:09:22,540 And just over that wall is the freshman dining hall, which looks like Hogwarts. 172 00:09:22,540 --> 00:09:24,570 If you don't believe me, Google it. 173 00:09:24,570 --> 00:09:26,410 >> But in any case, back to Sanders. 174 00:09:26,410 --> 00:09:30,620 So by day, we all know it as where CS50 takes place. 175 00:09:30,620 --> 00:09:34,990 By night, this place is also an incredible auditorium 176 00:09:34,990 --> 00:09:39,660 for a large amount of concerts, run not only by students but famous performers. 177 00:09:39,660 --> 00:09:41,690 For instance, Wynton Marsalis. 178 00:09:41,690 --> 00:09:44,400 Last year, we actually had Matt Damon as the recipient 179 00:09:44,400 --> 00:09:46,920 of the Arts First Medal of Honor. 180 00:09:46,920 --> 00:09:49,390 And then this year, we actually have Margaret Atwood. 181 00:09:49,390 --> 00:09:53,400 >> So there's a lot of awesome things about having a space that's not only 182 00:09:53,400 --> 00:09:58,270 driven for academics, but also for your extracurricular activities. 183 00:09:58,270 --> 00:09:59,830 >> RAMON: Now this week in tech news. 184 00:09:59,830 --> 00:10:03,080 DropBox has made quite a fuss lately, but I know nothing about this. 185 00:10:03,080 --> 00:10:04,880 >> DAVID: Well, at least this tweet went out 186 00:10:04,880 --> 00:10:06,670 of late, which you wouldn't mind reading-- 187 00:10:06,670 --> 00:10:08,080 >> RAMON: Wow, @DropBox. 188 00:10:08,080 --> 00:10:11,090 DMCA's take down in personal folders. 189 00:10:11,090 --> 00:10:12,090 This is new to me. 190 00:10:12,090 --> 00:10:15,760 >> DAVID: So DMCA, for those unfamiliar, is the Digital Millennium Copyright Act. 191 00:10:15,760 --> 00:10:19,200 And this is a US law that essentially governs the use and sharing, 192 00:10:19,200 --> 00:10:22,372 or prohibition of sharing, of copyrighted materials. 193 00:10:22,372 --> 00:10:24,330 Now it turns out, this is actually nothing new. 194 00:10:24,330 --> 00:10:27,330 Even though the internet was a bit abuzz with this story of late. 195 00:10:27,330 --> 00:10:29,670 DropBox does indeed analyze the files that you 196 00:10:29,670 --> 00:10:33,670 have in your DropBox if you attempt to share a file, like a movie that's 197 00:10:33,670 --> 00:10:36,210 copyrighted, or song that's copyrighted, or the like. 198 00:10:36,210 --> 00:10:39,320 >> Because if a company or movie studio determines, wait a minute. 199 00:10:39,320 --> 00:10:41,430 That is our movie, or that is our song, they 200 00:10:41,430 --> 00:10:44,260 can let DropBox know by sending this take down notice. 201 00:10:44,260 --> 00:10:48,112 DropBox then computes what's called a hash, which is a unique identifier that 202 00:10:48,112 --> 00:10:50,070 looks like a sequence of characters and numbers 203 00:10:50,070 --> 00:10:52,290 that, with very high probability, uniquely 204 00:10:52,290 --> 00:10:54,170 identifies that particular file. 205 00:10:54,170 --> 00:10:56,780 They then add that hash to a blacklist, and any time 206 00:10:56,780 --> 00:10:59,030 they notice you or me or anyone on the internet trying 207 00:10:59,030 --> 00:11:03,160 to share that same file, whereby that same file presumably has the same hash, 208 00:11:03,160 --> 00:11:04,270 they disallow it. 209 00:11:04,270 --> 00:11:06,110 >> So this is a very common approach. 210 00:11:06,110 --> 00:11:07,860 This has been done for some time. 211 00:11:07,860 --> 00:11:10,719 It doesn't mean that DropBox is snooping around your files. 212 00:11:10,719 --> 00:11:12,760 It doesn't mean that they're deleting your files. 213 00:11:12,760 --> 00:11:16,010 It simply means that if you're trying to proactively share a file that someone 214 00:11:16,010 --> 00:11:20,182 has claimed ownership of, they will clamp down in that case. 215 00:11:20,182 --> 00:11:21,390 RAMON: That was all above me. 216 00:11:21,390 --> 00:11:24,820 But what wasn't, recently, we also had an opportunity 217 00:11:24,820 --> 00:11:28,960 to visit Third Degree Glass Factory, founded by LaunchCode and Square 218 00:11:28,960 --> 00:11:31,400 co-founder, Jim McKelvey. 219 00:11:31,400 --> 00:11:35,580 >> DAVID: So, it turns out that the Third Degree Glass Factory was actually 220 00:11:35,580 --> 00:11:38,150 inspiration for Jim's company, Square. 221 00:11:38,150 --> 00:11:41,000 So Jim is quite the artisian when it comes to making glass. 222 00:11:41,000 --> 00:11:43,510 And he actually created these beautiful faucets out 223 00:11:43,510 --> 00:11:46,120 of glass in the glass factory's bathroom. 224 00:11:46,120 --> 00:11:49,360 Now as the story goes, a couple came in some time ago 225 00:11:49,360 --> 00:11:52,807 and asked if they could purchase such faucets for their own home. 226 00:11:52,807 --> 00:11:56,140 Jim, at the time, wasn't able to process credit card companies from these folks, 227 00:11:56,140 --> 00:11:58,450 and thus was born the inspiration for Square, 228 00:11:58,450 --> 00:12:01,850 a company that now allows you to do exactly that by swiping a credit 229 00:12:01,850 --> 00:12:05,530 card on your, for instance, iPhone with which to process payments. 230 00:12:05,530 --> 00:12:06,700 >> RAMON: I have a flip phone. 231 00:12:06,700 --> 00:12:11,475 And now, 60 seconds of David blowing glass. 232 00:12:11,475 --> 00:12:14,954 >> [MUSIC - THE BLACK KEYS, "EVERLASING LIGHT"] 233 00:12:14,954 --> 00:13:10,700 234 00:13:10,700 --> 00:13:12,700 >> RAMON: And now, some work from your classmates. 235 00:13:12,700 --> 00:13:15,970 You may recall this, from Pset 4's Breakdown. 236 00:13:15,970 --> 00:13:17,110 >> DAVID: Breakout, in fact. 237 00:13:17,110 --> 00:13:20,400 Which uses the Sanford Portable Library, a graphical user interface 238 00:13:20,400 --> 00:13:22,180 with which you can make games like this. 239 00:13:22,180 --> 00:13:25,802 It turns out, you may remember a game like this from 1989. 240 00:13:25,802 --> 00:13:27,417 Let's take a look. 241 00:13:27,417 --> 00:13:30,399 >> [VIDEO GAME SOUNDS] 242 00:13:30,399 --> 00:13:43,960 243 00:13:43,960 --> 00:13:46,470 >> DAVID: Now upon completing Pset 4, one of your classmates 244 00:13:46,470 --> 00:13:48,140 had this to say on Facebook. 245 00:13:48,140 --> 00:13:52,470 >> RAMON: More than 20 years ago, I bought this similar game, "Alleyway", for $25. 246 00:13:52,470 --> 00:13:54,284 I can't believe I've created it. 247 00:13:54,284 --> 00:13:56,950 DAVID: Now you may also recall, recently we headed down the road 248 00:13:56,950 --> 00:13:59,130 to MIT's Media Lab where our friends John Maloney 249 00:13:59,130 --> 00:14:03,020 and Mitchell Resnick, creators of Scratch, kindly sat down for a chat 250 00:14:03,020 --> 00:14:03,520 with us. 251 00:14:03,520 --> 00:14:05,228 At the time, they gave us a sneak preview 252 00:14:05,228 --> 00:14:07,630 of Scratch Jr., a new version of Scratch, 253 00:14:07,630 --> 00:14:10,490 in development, that's targeted at students even younger than those 254 00:14:10,490 --> 00:14:12,545 for whom the original Scratch version was born. 255 00:14:12,545 --> 00:14:15,170 Now, the media lab is in the process of doing a bit of campaign 256 00:14:15,170 --> 00:14:17,820 to raise support for the continued development of Scratch 257 00:14:17,820 --> 00:14:20,260 Jr. In fact, among the things they are hoping to do-- 258 00:14:20,260 --> 00:14:22,820 >> RAMON: Is release an iPad version this year, 259 00:14:22,820 --> 00:14:25,470 hoping to release an Android version later this year, 260 00:14:25,470 --> 00:14:28,685 and develop resources in curricula for teachers and students alike. 261 00:14:28,685 --> 00:14:30,560 If you'd like to contribute to this campaign, 262 00:14:30,560 --> 00:14:33,610 do just head to this Kickstarter URL here. 263 00:14:33,610 --> 00:14:36,170 Or, for more information, take a look at this clip. 264 00:14:36,170 --> 00:14:46,730 >> [MUSIC PLAYING] 265 00:14:46,730 --> 00:14:48,650 >> MARINA: We're working on Scratch Jr., which 266 00:14:48,650 --> 00:14:51,340 is a programming language for young kids, specifically designed 267 00:14:51,340 --> 00:14:53,005 for five to seven-year-olds. 268 00:14:53,005 --> 00:14:56,810 And it's designed with them in mind, so it's developmentally appropriate. 269 00:14:56,810 --> 00:15:01,750 And children can create animated stories, interactive games, collages, 270 00:15:01,750 --> 00:15:05,410 or anything they imagine. 271 00:15:05,410 --> 00:15:08,325 >> SPEAKER 7: I like Scratch Jr. because there's 272 00:15:08,325 --> 00:15:12,430 so many programs that you could make. 273 00:15:12,430 --> 00:15:14,864 >> SPEAKER 8: It's like you can make your own movie. 274 00:15:14,864 --> 00:15:19,480 >> SPEAKER 9: You basically get to make your own game and do it yourself. 275 00:15:19,480 --> 00:15:21,120 >> SPEAKER 10: Do you know what that does? 276 00:15:21,120 --> 00:15:22,120 SPEAKER 11: No, tell me. 277 00:15:22,120 --> 00:15:24,720 278 00:15:24,720 --> 00:15:26,864 >> SPEAKER 10: It makes it wait 50 seconds. 279 00:15:26,864 --> 00:15:27,530 SPEAKER 11: Wow. 280 00:15:27,530 --> 00:15:29,742 How did you know? 281 00:15:29,742 --> 00:15:32,157 >> SPEAKER 10: Because the clock. 282 00:15:32,157 --> 00:15:34,100 And it's set to 50. 283 00:15:34,100 --> 00:15:36,450 >> MARINA: We design Scratch Jr. to match the development 284 00:15:36,450 --> 00:15:37,840 abilities of young children. 285 00:15:37,840 --> 00:15:41,530 We look at cumulative social personal capabilities, 286 00:15:41,530 --> 00:15:44,290 and we design the features of Scratch Jr. 287 00:15:44,290 --> 00:15:46,230 To match what young children can do. 288 00:15:46,230 --> 00:15:49,370 We work with teachers, we work with children, we work with parents. 289 00:15:49,370 --> 00:15:52,400 And we observe what they were able to do, what they were not able to do, 290 00:15:52,400 --> 00:15:56,070 and we went back and redesigned Scratch Jr. many, many, many times 291 00:15:56,070 --> 00:16:00,430 so we can really be a tool for young children. 292 00:16:00,430 --> 00:16:01,960 >> RAMON: That's it for CS50 Live. 293 00:16:01,960 --> 00:16:04,780 Thanks to all the contributors and the staff behind the camera. 294 00:16:04,780 --> 00:16:07,800 >> DAVID: Thanks so much to Ramon for filling in for my voice today. 295 00:16:07,800 --> 00:16:13,245 >> RAMON: This was CS50, and this is 12 programmers blowing glass. 296 00:16:13,245 --> 00:16:16,165 >> [MUSIC - AMERICAN AUTHORS, "BEST DAY OF MY LIFE"] 297 00:16:16,165 --> 00:17:10,058 298 00:17:10,058 --> 00:17:11,849 SPEAKER 12: And that's how you make a bowl. 299 00:17:11,849 --> 00:17:14,470 This CS vickvee-- Ah! 300 00:17:14,470 --> 00:17:15,839 And now I made the blooper reel. 301 00:17:15,839 --> 00:17:18,584 Fantastic. 302 00:17:18,584 --> 00:17:44,427 >> [MUSIC PLAYING]