So for our next unplugged activity we are going to be looking at introducing the concept of a variable using an activity. Now, what I've done for you here is we're using an activity from code.org and they have a description, fairly detailed, about an activity that you could do with students in your classroom. So I wanted to sort of vicariously maybe do it for you. I've modified it a little bit because I don't have students here in the classroom to bring in. But it's possible that this would also be useful for you to use in reviewing the key takeaways of that activity with your students. All right, so the key thing that we're using to introduce variables believe or not are poems. So let's say I want to write a nice poem, congratulatory poem for students in my class. Or maybe Serena is a student in my class. So I could say my student Serena, standing proud is a fine example for the crowd. But she's not my only student. I also got Chris. Well, I could say, my student Chris, standing proud is a fine example for the crowd. But those aren't my only students. Well, I have Neymar. My student Neymar, standing proud is a fine example for the crowd. Yeah, I have a very select classroom here. But it's kind of nice to use the energies of sports figures that students look up to. And by the way, I got these from a code.org video, so I feel okay about using them. All right, but boy if I have a lot of students in my class this is going to take me a really long time, especially instead of just copying the words and putting them out there. What if I was writing this out by hand? How long would that take? Yeah, that's going to be a really long time to write out a poem for every student in my class or my school. So one of the things I'm going to point out here is that this really are all the same poem, there's only one thing that changes each time. That's the Serena, Chris, and Neymar. So what could we do with that? Hm, well let's see. We could realize that essentially, yes, there is essentially a template that is the same for everybody. And I could just write out that template and then, depending on who I want to have the poem for, I could maybe just copy their name down into this blank line that I put there. And then I'd have this personalized for Serena. But when I was ready for Chris, I could copy his name down and put it into that blank. And, don't want to leave out Neymar, all right. So, this could be a way of much more quickly producing a poem for each person. But we need to understand that there's this blank, right? And we're going to call that a placeholder. And it's really good idea because we could have more than one placeholder sometimes, that we'd give it a name that's hopefully descriptive of what goes in that place. So, I decided to use First Name because I'm using the first name of my potential students here. So one of the other things we then want to say is hey, what do we fill in there? Well Serena's going to have a first name. And one time the first name variable is going to have Chris in it, and then another time, we'd have Neymar in there. So depending on who I was picking to write this poem for, I would sub in the appropriate first name. So the key that we want to take away from this is that variables are simply placeholders where we store data that maybe will change depending on who we're writing a poem for or depending on when we're running a program. So variables just serve as placeholders to hold data. Now, there are other places that you're probably familiar with, maybe in the world of computing, that use placeholders. All right, your experience might have varied based on your experience playing video games. But the one thing I want to point out here is that placeholders are a really common way that our students are used to seeing variables. And there's a lot of words up here but basically there's the same thing for each player. On the left we have Player 1, on the right we have Player 2. But some things that we would keep track of is your score. Maybe if we have life points that you get used up and then after when they're gone, you're dead. And so that's important and moreover there need to be different score and life points for Player 1 as there are for Player 2. That seems pretty obvious. Also obvious, those values change over time. Player 1's name, Player 2's name, maybe those don't change for the entire game, but we still need to have those as a variable because we want to display them in our game. And then maybe there's even these, I don't know what these things are at the bottom, POWs. But they look like things [LAUGH] that are maybe dynamic and change in terms of many you have at any given point in time. So video games are maybe a little bit more closely related to computing then poems, but can be a really great way to get students understanding placeholders.
