11: Poetic Variables

Activity 11: Poetic Variables

<Mobile

Activity Description

15 mins.

Variables allow for a lot of freedom in computer science. This lesson helps to explain what variables are and how we can use them in many different ways. This activity helps set up the next one, in which the girls will use a variable to improve their Paint Pot app.

Objectives

By completing this activity girls will

identify variables and determine their values.
define and call variables in the context of real-life activities.
create situations which require the use of variables.
use teamwork to enrich creative game play.

How to Implement

Call four volunteers to the front of the room and line them up. Let the girls know that you are going to write a poem for each of them.
On the board or chart paper write this sentence, using the first girl’s name (suppose it’s Jill):

My girl Jill, standing proud is a fine example for the crowd.

Erase the board or flip to a new sheet of paper and for the next volunteer (we'll say her name is Annie) write:

My girl Annie, standing proud is a fine example for the crowd.

Again, erase the board or flip the paper and write the poem for your next volunteer:

My girl Jenny, standing proud is a fine example for the crowd.

As you write a poem for the final volunteer, inquire as to whether everyone in the group would like a poem written about them. Maybe the whole school (or town, or museum, etc.)? How long would that take? Can we do this more efficiently?
The girls will likely pick up on the fact that only one word is changing, and that word is simply a person's name. Help them see the location by circling Jenny's name and writing "firstName" next to it. Explain that it would take a long time to write a poem for everyone if you couldn’t start until you knew who you were writing about.
Pose these questions to the girls:
- How long do you think it would take to make a video game if you couldn't start until you knew every person's username?
- How expensive would video games be if they had to be created separately for each person?
- How do you think we can get around that?
By this time, it's quite likely that the group will come up with the idea of having a placeholder. If so, they're most of the way into understanding where this lesson goes.
Ask the girls what would we call that placeholder? We need to call it something that makes sense. We wouldn’t want to call it “age” if it was a placeholder for their name, right?
Tell the girls that you’re going to add some more volunteers. Give them each a piece of paper to write their names on, and have them tuck their paper inside individual envelopes labeled firstName.
Now, write the poem on the board with a blank space labeled “firstName” where the girl’s name will go. Now ask a girl to pull her name from her envelope, and that’s what you’ll write in the space. When you erase the board, only erase the portion with the last girl’s name in it.
Call on another girl to show her variable. Repeat as many times as is entertaining.
Introduce the concept of variable, a name or placeholder for a piece of data that can change in value.
Remind the girls that there is a lot of important, everyday information that changes value. Here are some examples:
- your age
- your height
- your location
- today’s date
Explain that when we take complex data and simplify it, that is called abstraction. Using variables is just one way to practice abstraction.
Wrap-up discussion:
- Ask the girls if they can you think of anywhere they’ve seen variables before?There is at least one variable at the top of most homework handouts? Can you think of what it could be?
- Why do you think that programmers do not put spaces in variable names?
- Variables can be used to store numbers, too.Suppose I have envelopes labeled num1 and num2, then I write num1+num2, then I write num1+num2? What happens if the “num1” envelope contains the number 4 and “num2” contains the number 5?
- Can you think of a way we could use variables in our PaintPot app?

Resources & Materials

envelopes (4 or 5)
slips of paper (4 or 5)
chart paper or whiteboard

Notes to Educators

Background Information: There are two types of variables, local variables and global variables. When you create variables, you’ll have to think about whether you want to use the variable at multiple places in your code or if you want to use it in just one place.

Global variables can be used anywhere. You can never reuse a name when using a global variable. If you did, your app won’t know which variable to use. Luckily Thunkable won’t allow you to create two variables with the same name. If you’re in doubt of which variable type to use, use global.

Local variables can only be used at one spot in your code. If you need a variable to keep track of something in just one place, use a local variable. The local variable will only be able to be used inside the “local variable” block and Thunkable won’t let you use it outside of it. Unlike global variables, local variables can have names that have already been used.

Standards Alignment

Interim CSTA K-12 Computer Science Standards: 1B-A-2-1, 1B-A-5-3, 2-A-5-7, 2-A-6-10

Next Generation Science Standards: 3-5-ETS1-1, 3-5-ETS1-2

Common Core Standards for English Language Arts: W.5.2d, W.5.6, SL.5.1, L.5.6, SL.6.1, SL.6.6, RST.6.3, RST.6.4

Attribution

This work, Poetic Variables, is a derivative of “Variables in Envelopes” by code.org CC BY-NC-SA 4.0, licensed under CC by SciGirls

Report abuse