[MUSIC PLAYING] RAMON: Hello, world. This is CS50 Live. I'm Ramon Galvan, filling in today for David-- DAVID: Who's lost his voice. RAMON: Today, he'll be the Andy Richter to my Conan O'Brien. As we tour Harvard campus today, blow glass today. But first-- DAVID: And so, so much more in today's episode. But first, a look at a recent field trip. RAMON: Recently, this past weekend, we took a trip to St. Louis to be visit LaunchCode for the first ever CS50 Hackathon outside of Cambridge. And our own Shelley Westover has put together a little scissor reel to show you what happened. DAVID: Let's take a look. SPEAKER 1: So I'm here to announce today that David Mayo and a team of 12 educators from Harvard University are coming to St. Louis, Missouri on March 28. DAVID: We are so pleased to announce the first ever CS50 Hackathon, that will be going on the road to St. Louis. [MUSIC - AMERICAN AUTHORS, "BEST DAY OF MY LIFE"] SPEAKER 2: Woah, that was a lot faster than I expected. SPEAKER 3: Shelley's driving the bus. Oh, super wet. Wait. Second thoughts. I'm going. I'm not looking back. Oh no! Damn it! It's all over. DAVID: And what you all have been waiting for here tonight is our first ever on-the-road CS50 Hackathon. [CHEERS] [INAUDIBLE] put faces to the YouTube views, I guess. [LAUGHTER] SPEAKER 4: And this is CS50, and this is LaunchCode STL. DAVID: The ultimate goal is to get to at least midnight, at which some excellent donuts will be served. And we'll be here a bit longer after that, but you should be proud if you can make it all the way we to midnight tonight. SPEAKER 5: 200 or so people are here tonight, and we're all really excited to be a part of Harvard's CS50 and have you part of our city. Glad to have you. SPEAKER 2: End on a joke. SPEAKER 6: What's the first sign of a nosy pepper? It's jalapeno business. SPEAKER 2: Hey, Chad. They don't love you. Sorry, bud. RAMON: You may also recall from last time, code.org. A non-profit that has been getting everyone excited about computer science. And it turns out that founder Hadi Partovi was actually a former CS50 TF, and he wants to say hello. HADI: Hello, world. My name is Hadi Partovi. I run an organization called code.org. We're best known for our Hour of Code Campaign. That's something we launched for the first time last year in 2013, and the last three months the Hour of Code has already reached 30 million students, showing that computer science is something that is applicable and something that anybody can learn. It's useful whether you want to become a doctor, a lawyer, an astronaut, or even the president. And those of you who are learning it in CS50 today, you're learning things like how to write a for loop or repeat loop, an if-then statement, or how to program your own functions. These are concepts that anybody can learn, and are fundamental to how all of computing around us works. I myself was a CS50 TF when I first went to Harvard. So it's exciting for me to record this video for you all. So enjoy yourselves. This is CS50. RAMON: You may also know that Mark Zuckerberg, created the Facebook back in his college dorm room. This is how it originally looked like. Also, you may not know that the original URL was not the Facebook or Facebook.com. DAVID: No, rather, it was this one here. RAMON: Roam.175-29.student.harvard.edu. DAVID: Which was the host name of Mark's computer in his dorm room. And in fact, pictured here is Mark with Chris Hughes and Dustin Moskovitz, two of the students with whom he went on to found Facebook itself. Now, Mark comes back to campus from time to time, and in fact, in 2005, he visited CS50 with Professor Micheal D. Smith and gave a guest lecture. In fact, if you look really closely, you can see Mark down up front. But let's take a look at a clip. MARK: Wanting to look people up, I think, is kind of a core human desire. Right? I think that people just want to know stuff about other people. So I think that providing an interface where people could just type in someone's name and get some information about them is generally a pretty useful thing. So growth has been pretty good. It was tough to figure out exactly how to gauge it, because when we did college, we opened it up at Harvard. Then we opened it up at a couple of colleges around Harvard. And the idea was always, we are really short on money and equipment, so while getting as little as possible, we want to maximize our growth. So we want to launch at the schools that we think are going to grow the quickest based on the fact that the people at those schools are going to have the most number of friends at the schools that we're already at. We took a different approach for high school, because we could just launch it everywhere at the same time. So we didn't really know how it was going to grow. I think it's growing at more than 5,000 people a day, which is pretty good. RAMON: For the full lecture, click on this link. DAVID: But not yet. You can get the full hour of Mark's talk there on the internet. RAMON: And now, let me introduce a current Harvard undergraduate, Sean, who wants to give you at tour of Harvard's campus. SEAN: Hi there. My name's Sean and I'll be your tour guide today. Originally hailing from New York City, I'm actually now a sophomore living Cabot house-- best house-- concentrating in neurobiology on the mind-brain behavior track, with a secondary in visual environmental studies on the film production track. Welcome to Harvard. Hi there. Welcome to the Science Center Plaza. It's said that over 10,000 people will come through these doors every single day, because there's a large number of things you can do in it. So one of the things I love about the Science Center Plaza is that during the summer, it becomes even more of a hub. Because we have all of these food trucks that line up from all different places in Boston. And in addition, we have crafts fairs, we have a weekly petting zoo, we have chessboards and bean bag chairs. So everyone loves to come out, whether to do homework or just chat, or just grab a bite to eat. So looking over here now, we have Memorial Hall Complex, which is exactly where CS50 lectures are held. So if you want to follow me to our next stop, we'll talk more about it there. So welcome to the inside of Memorial Hall Complex. Now, there's some really cool things about this building that you can see right here. First thing you notice is all of that stained glass. This building actually contains the second largest amount of secular stained glass in North America. Now why? This place was actually founded in 1870 as a war memorial, commemorating the lives lost of Harvard undergraduates who fought for the Union during the Civil War. Now, this building is filled with history. But it's also filled with a lot of cool other things. Some of you may recognize this building. It's actually the place where CS50 lectures take place. So this is actually just outside of Sanders Theatre, where David Malan actually gives his lectures. This space is really cool because it's actually three functions. First, there's Sanders Theater. But also, below us, there's a bunch of classrooms and rehearsal rooms. And just over that wall is the freshman dining hall, which looks like Hogwarts. If you don't believe me, Google it. But in any case, back to Sanders. So by day, we all know it as where CS50 takes place. By night, this place is also an incredible auditorium for a large amount of concerts, run not only by students but famous performers. For instance, Wynton Marsalis. Last year, we actually had Matt Damon as the recipient of the Arts First Medal of Honor. And then this year, we actually have Margaret Atwood. So there's a lot of awesome things about having a space that's not only driven for academics, but also for your extracurricular activities. RAMON: Now this week in tech news. DropBox has made quite a fuss lately, but I know nothing about this. DAVID: Well, at least this tweet went out of late, which you wouldn't mind reading-- RAMON: Wow, @DropBox. DMCA's take down in personal folders. This is new to me. DAVID: So DMCA, for those unfamiliar, is the Digital Millennium Copyright Act. And this is a US law that essentially governs the use and sharing, or prohibition of sharing, of copyrighted materials. Now it turns out, this is actually nothing new. Even though the internet was a bit abuzz with this story of late. DropBox does indeed analyze the files that you have in your DropBox if you attempt to share a file, like a movie that's copyrighted, or song that's copyrighted, or the like. Because if a company or movie studio determines, wait a minute. That is our movie, or that is our song, they can let DropBox know by sending this take down notice. DropBox then computes what's called a hash, which is a unique identifier that looks like a sequence of characters and numbers that, with very high probability, uniquely identifies that particular file. They then add that hash to a blacklist, and any time they notice you or me or anyone on the internet trying to share that same file, whereby that same file presumably has the same hash, they disallow it. So this is a very common approach. This has been done for some time. It doesn't mean that DropBox is snooping around your files. It doesn't mean that they're deleting your files. It simply means that if you're trying to proactively share a file that someone has claimed ownership of, they will clamp down in that case. RAMON: That was all above me. But what wasn't, recently, we also had an opportunity to visit Third Degree Glass Factory, founded by LaunchCode and Square co-founder, Jim McKelvey. DAVID: So, it turns out that the Third Degree Glass Factory was actually inspiration for Jim's company, Square. So Jim is quite the artisian when it comes to making glass. And he actually created these beautiful faucets out of glass in the glass factory's bathroom. Now as the story goes, a couple came in some time ago and asked if they could purchase such faucets for their own home. Jim, at the time, wasn't able to process credit card companies from these folks, and thus was born the inspiration for Square, a company that now allows you to do exactly that by swiping a credit card on your, for instance, iPhone with which to process payments. RAMON: I have a flip phone. And now, 60 seconds of David blowing glass. [MUSIC - THE BLACK KEYS, "EVERLASING LIGHT"] RAMON: And now, some work from your classmates. You may recall this, from Pset 4's Breakdown. DAVID: Breakout, in fact. Which uses the Sanford Portable Library, a graphical user interface with which you can make games like this. It turns out, you may remember a game like this from 1989. Let's take a look. [VIDEO GAME SOUNDS] DAVID: Now upon completing Pset 4, one of your classmates had this to say on Facebook. RAMON: More than 20 years ago, I bought this similar game, "Alleyway", for $25. I can't believe I've created it. DAVID: Now you may also recall, recently we headed down the road to MIT's Media Lab where our friends John Maloney and Mitchell Resnick, creators of Scratch, kindly sat down for a chat with us. At the time, they gave us a sneak preview of Scratch Jr., a new version of Scratch, in development, that's targeted at students even younger than those for whom the original Scratch version was born. Now, the media lab is in the process of doing a bit of campaign to raise support for the continued development of Scratch Jr. In fact, among the things they are hoping to do-- RAMON: Is release an iPad version this year, hoping to release an Android version later this year, and develop resources in curricula for teachers and students alike. If you'd like to contribute to this campaign, do just head to this Kickstarter URL here. Or, for more information, take a look at this clip. [MUSIC PLAYING] MARINA: We're working on Scratch Jr., which is a programming language for young kids, specifically designed for five to seven-year-olds. And it's designed with them in mind, so it's developmentally appropriate. And children can create animated stories, interactive games, collages, or anything they imagine. SPEAKER 7: I like Scratch Jr. because there's so many programs that you could make. SPEAKER 8: It's like you can make your own movie. SPEAKER 9: You basically get to make your own game and do it yourself. SPEAKER 10: Do you know what that does? SPEAKER 11: No, tell me. SPEAKER 10: It makes it wait 50 seconds. SPEAKER 11: Wow. How did you know? SPEAKER 10: Because the clock. And it's set to 50. MARINA: We design Scratch Jr. to match the development abilities of young children. We look at cumulative social personal capabilities, and we design the features of Scratch Jr. To match what young children can do. We work with teachers, we work with children, we work with parents. And we observe what they were able to do, what they were not able to do, and we went back and redesigned Scratch Jr. many, many, many times so we can really be a tool for young children. RAMON: That's it for CS50 Live. Thanks to all the contributors and the staff behind the camera. DAVID: Thanks so much to Ramon for filling in for my voice today. RAMON: This was CS50, and this is 12 programmers blowing glass. [MUSIC - AMERICAN AUTHORS, "BEST DAY OF MY LIFE"] SPEAKER 12: And that's how you make a bowl. This CS vickvee-- Ah! And now I made the blooper reel. Fantastic. [MUSIC PLAYING]