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Traveling Circuits
Lesson 2
Fun with Functions
a one hour
introductory activity
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Lesson 2: Fun with Functions
Main Goal:
Help students grasp the concept of variables while teaching them to run functions.
Overview:
To begin, you will show the students an art project and share steps that they can
take to re-create it. These steps should be repetitive and simple to execute. In this
lesson, we will create a keychain using pipe cleaners and various types of beads.
Once students are familiar with the technique needed to create their keychain,
have them try to fit the whole “program” onto a special piece of paper.
Objectives: Students will
• • • • Learn to convert real-world activities into instructions
Gain practice coding instructions with symbols
Gain understanding of the use of variables
Learn why functions are useful in the world of coding
Materials and Preparation:
Estimated lesson time: 1 hour
Estimated prep time: 20 min
Materials
• Symbol Key (1 per group)
• Program Paper (1 per person)
• Beads (4 per person)
• Hoops (2 per person)
• Special Bead (1 per person)
• Bead Baggie (1 per person)
• Pipe Cleaner (1 per person)
• Rubber Band (1 per person)
Preparation
• Print out one Symbol Key for each group
• Print a Program Paper for each person
• Package Beads, Hoops, and Special Bead into packets for easy grabbing
• Twist Pipe Cleaners in half around the rubber band to prepare for beading
• Create a sample keychain to display for class
Key Lesson
Vocabulary:
Algorithm - A series of instructions on how to accomplish a task
Function - A piece of code that can be called over and over
Program - A set of code that a machine can follow
Variable - A symbol that can be used as placeholder for an unknown (or changing) value
TRAVELING CIRCUITS - SERIES 1 COMPUTER SCIENCE
© 2013 www.thinkersmith.org
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Traveling Circuits
TM
Series 1: Hands-On Activity 2
Lesson Plan
Introduce:
Before you pass out supplies, show the students the pre-made keychain and let
them know that they are going to learn how to create one for themselves. Tell
them to listen carefully while you teach them the algorithm describing how the
keychain was built.
Put a bead on and twist, put another bead on and twist.
Put on a hoop and twist. Bead, twist, bead, twist, hoop, twist.
Add a special bead, then curl the tail like a snail.
Did everyone get that? One more time, it’s:
Bead, twist, bead, twist, hoop, twist. Bead, twist, bead, twist,
hoop, twist. Special bead, curl like a snail.
Have the class repeat the sequence along with you a time or two, until you are
confident that they are familiar with the pattern.
Adjustments:
Grades K-3
• Try this lesson all together as one class.
• Students may need to be guided toward discovering what patterns repeat.
• Read through the finished program several times, challenging them to jump up to
the “definition” for f1 when you point to the symbol “calling” f1 in the program.
Grades 4-6
• The lesson should go as expected for this age.
• If you have extra time, try having them do the same thing for the song “Head,
Shoulders, Knees and Toes”.
Grades 7+
• This can be an individual activity.
• Challenge students to apply this method to something else from life, such as a song,
a dance routine, or a recipe.
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Lesson 2: Fun with Functions
Steps:
1. Show students sample keychain.
2. Verbally explain how the keychain was made.
3. Have students repeat sequence.
4. Attempt to document “program” on small piece of Program Paper.
5. Point out that you are running out of room.
6. Challenge students to use f1 and f2 sections for sequences that repeat.
7. Let students fill out their Program Papers in groups.
8. Share a few programs that the groups created.
9. Have groups translate their programs into physical keychains.
10. Show off keychains to classmates.
Kickstart:
Once the class is comfortable with the pattern, let them know you’re going to write
it down so that they have a “program” to follow. Tell them that you don’t want to
write the words over and over, so you’re going to draw symbols to make it easier.
Describe what each one means, according to the diagram below:
Add Bead
Add Hoop
Twist Pipe Cleaner
Add Special Bead
Curl Ends of Pipe Cleaner
These symbols will come in handy later.
Now, have the class start helping you fill in the “PROGRAM” section of the Program
Paper. You should be able to get through about six symbols before the class
notices that something is wrong. If they don’t help them out by asking, “Am I going
to be able to get all the way through this program, here?”
They’ll likely confirm that you won’t, but may have no idea where to go from
there. Unfold the Program Paper (or grab a new one) and suggest that there is a
solution. Let them know that these papers have two special areas where you can
store instructions that you use multiple times, those areas are called “functions”. In
order to “call” the function, you only need to place the name of the function in the
program box where you want the defined actions.
TRAVELING CIRCUITS - SERIES 1 COMPUTER SCIENCE
© 2013 www.thinkersmith.org
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Traveling Circuits
TM
Series 1: Hands-On Activity 2
The Activity: Pass a Program Paper to each group, and let the students work together to ponder
through what your words just meant. How will they find repeating sequences,
program them into the function areas, then call the functions to make their
program accurately replicate your keychain?
Travel around and answer questions, but try not to give any clear directives. See
what the class can work out.
Give the students about five minutes, then ask if anyone wants to share their
solutions. Review solutions as a class, analyzing for accuracy. How many solutions
were found that will work? Which solution takes the fewest number of steps?
Duplicate one of the solutions to keep on display for the class.
Once the groups have all filled in their Program Papers with a program that gives
them a correct keychain, ask the class if they’re ready to create their bauble. Pass
out the packets of pre-prepared beads.
When the students have their beads, but before you give them their pipe cleaners,
go back to the program on display. Point to one of the bead symbols, and highlight
that you don’t know what color of beads the students might have ended up with.
You may not even know what size hoop they have, or what shape their special bead
is. Ask them if that should prevent you from letting them know what order to put
their bead, hoops, and special bead. Emphasize again that *this person* may have
red beads, while *that person* has blue, but regardless, we can use the symbols
that we drew as placeholders for the various options. In fact, another name for
those placeholders is “variables”. Variables are words or symbols that you can use in
your program that indicate where something will go, even if you don’t quite know
what that something is before you write the code.
Now that everyone understands, functions and variables, give them their pipe
cleaners and turn them loose to create their keychains!
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Lesson 2: Fun with Functions
PROGRAM
As you start filling in the rectangles with symbols (variables), it
will soon become apparent that you will not be able to display
the entire program using only these eight spots.
f1
f2
PROGRAM
Add the function boxes, f1 and f2, for repeating
sequences, then call the sequence from inside the
program.
f1
f1
f2
TRAVELING CIRCUITS - SERIES 1 COMPUTER SCIENCE
© 2013 www.thinkersmith.org
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Traveling Circuits
Symbol Key
Lesson 2: Fun with Functions
TM
Fun with
Functions Key:
Add Bead
Add Hoop
Twist Pipe Cleaner
Add Special Bead
Curl Ends of Pipe Cleaner
TRAVELING CIRCUITS - SERIES 1 COMPUTER SCIENCE
© 2013 www.thinkersmith.org
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Traveling Circuits
TM
Program Paper
Lesson 2: Fun with Functions
f1
f2
PROGRAM
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TRAVELING CIRCUITS - SERIES 1 COMPUTER SCIENCE
© 2013 www.thinkersmith.org
Traveling Circuits
TM
Series 1: Hands-On Activity 2
Here are some samples of the
keychains described in the
lesson. Feel free to change the
algorithm to suit the age group
of your class.
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Lesson 2: Fun with Functions
TRAVELING CIRCUITS - SERIES 1 COMPUTER SCIENCE
© 2013 www.thinkersmith.org
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