Slinky Intervals: Interactive Music Theory Fundamentals Pt. 1
- Nicholas Shea
- Dec 2
- 7 min read
Updated: Dec 3
This is the first post in a series that describes hands-on activities I use in Theory 1 to help students understand more abstract concepts, like interval sizes, and keep them engaged at 7:30 am.
Intervals
I don't know a single theory instructor who truly enjoys teaching intervals. There are so many fiddly bits, even though all we inevitably want is for students to be able to recognize them in the context of a key, a chord, or scale. Following Michael Rogers, intervals inhabit a tricky position in the fundamentals sequence, creating a pedagogical chicken-or-the-egg situation; namely, do you start with scales or intervals first?
Starting with scales allows students to have a tonal frame of reference for select intervals, typically as they relate to scale-degree 1. The upshot is that you really only need to know the difference between whole steps and half steps to get started. However, most students will only truly be fluent with the C-major collection, perhaps followed by F and G, meaning chromatic intervals will still escape them unless they're also proficient at (1) understanding the intervallic quality between any two scale degrees, and (2) manipulating these relationships while keeping in mind the fixed half steps between C-B and E-F.
Starting with intervals is equally complex. Students ultimately need to focus first on the generic interval between any two pitches, then consider the following manipulations:
A sharp on the top note expands the interval.
A flat on the top note contracts the interval.
A sharp on the bottom note contracts the interval.
A flat on the bottom note expands the interval.
Things then get trickier when both sharps and flats are involved while also considering diatonic half steps.
In semesters past, I drew countless lines of varying lengths above a staff to show how sharps, flats, or natural signs change the size and quality of an interval. One handout included the following examples.
Example 1. Thirds of varying qualities, their total number of half steps represented using blocks.
It doesn't take much to intuit how students might become confused. Despite my best efforts, saying again and again "G to B is a 3rd, regardless of what intervals we tack on," students often failed to disentangle the number of semitones from the generic interval size. Thus, the augmented third of G to B# was incorrectly reported to be a number of things: a major third, a perfect fourth, and occasionally "a fifth."
After spinning my wheels for two academic years, I reflected on alternative ways to reach students. Some way to uncomplicate this finicky topic. I needed to cut through the monotony of counting half steps. And I needed students to understand the expansion and contraction of intervals. Eventually I realized I needed something tactile.
The slinky activity
The slinky activity is designed to help students realize:
Generic intervals are fixed.
A flat on the bottom or a sharp on the top of an interval expands it.
A flat on the top or a sharp on the bottom of an interval contracts it.
The value of knowing the interval quality between any two pitches in the C-major collection.
Materials
Painter's tape.
A plastic slinky. (Or multiple in different colors.)
Two music stands.
Two sets of single-sided 8.5''x11'' pages with generic note names printed on them (A,B,C,D,E,F, G).*
Two sets of single-sided 8.5''x11'' pages with a sharp and flat printed on them.*
A large-ish space.
At least four student volunteers.
*I laminated these. They're less likely to fall off the stand.
Getting set up for class [see the following Example 2]
Place 13 strips of painters tape on the floor (or on the back wall) at the front of the classroom where students can see them. The strips should be evenly spaced. Leave at least 6'' of space between each strip.
(Optional). Write the numbers 0–12 above the strips for ascending intervals. Write 12–0 below the strips for descending intervals.
Place two stands on either side of the 13 strips. Make sure they're in front of the 13 strips of tape.
Place the generic note-name pages face down on the left side of the stands. Then, place the accidental pages next to them on the right.
Example 2. How to set up the classroom space for the slinky activity.
Introduction
Start the class by holding the slinky in your hands. Then, hand one end to a student and slowly move away from them. As you do, suddenly stop and ask, "What is this thing we're holding?" Move away again, then ask, "Is this still a slinky?" Now move toward the student until the slinky is almost completely contracted, then ask one more time: "Is this still a slinky?"
Explain to students that intervals are like slinkies. Once the generic interval size is established — a third, fifth, sixth, and so on — it retains its generic quality. A purple slinky is still a purple slinky no matter how you stretch it. A third is still a third no matter how many accidentals you put on either end.
Begin the activity
Ask for at least four volunteers: two to hold the slinky and two to place the notes and accidentals pages. (You can also do six volunteers: two on the note names, two on the accidentals, and two slinky holders.)
Explain: two students will hold the ends of the slinky. The crowd will then direct one of the slinky holders to move to the strip of painter's tape that correctly represents the total number of half steps in the interval.
Outline the following steps. I like to summarize these on the board.
Part 1: Generic intervals
The instructor indicates if the interval is ascending or descending.
Ascending: the left slinky holder moves.
Descending: the right slinky holder moves.
Note-name volunteers pick a note at random and place it on the stand. For additional fun, don't let the slinky holders see these note names.
Students in the audience say the generic interval out loud simultaneously. ("Sixth!")
Students in the audience say the quality of the current interval out loud simultaneously. ("Major sixth!")
Students in the audience direct the moving slinky holder to the correct tape strip.*
The instructor talks them through the answer.
Students sing the interval, e.g., a major sixth, by dividing the audience into halves.
Left half: sing bottom note, D.
Right half: sing top note, B.
You could also have all students sing the bottom note, D, then have the right half of the room progressive sing up by half step until you reach the major sixth.
In the mock example below, the interval is an ascending sixth between D and B — a total of 9 half steps. The student on the right (green circle) moves in response to the audience's directions.
Note: I like to do this "The Price is Right" style, with students yelling out the correct answers. Other instructors may opt to have students raise their hands instead.
Example 3. Using a slinky to realize the generic ascending interval between the notes D and B. The student on the right (green circle) moves according to the audience's directions.
Part 2: Chromatic intervals
Slinky holders step to the side, away from the tape strips.
Note-name volunteers add a sharp, flat, or natural to the existing note names, placing them on the music stands for the audience to see. (e.g., D#, Bb)
Students in the audience write down how this changes the number of half steps in the interval. You can have the following on the board for reference:
Top note, sharp: increase by 1 half step.
Top note, flat: decrease by 1 half step.
Bottom note, sharp: decrease by 1 half step.
Bottom note, flat: increase by 1 half step.
Slinky holders return. If ascending, the left slinky holder stays at 0 while the right slinky holder prepares to move. If descending, vice versa.
Students in the audience direct the moving slinky holder to the correct tape strip based on the new accidentals.
The instructor talks them through the answer. See Example 5.
Q: "What's the generic interval?" A: "Sixth."
Q: "What happens when we add a sharp to the lower note? The interval gets..." A:"Smaller."
Q: "What happens when we add a flat to the top note? The interval gets..." A: "Smaller."
Q: "We started with a major sixth. If we sharp the bottom note, D, it becomes?" A: "Minor sixth."
Q: "And if we also put a flat on the top note, B?" A: "Diminished sixth."
Sing through this process:
Start with the major sixth.
Have the bottom-note singers (left side of audience) sing their note up a half step.
Have the top-note singers (right side of audience) sing their note down a half step.
The resulting interval should sound like a perfect fifth.
Repeat Parts 1 and 2, changing the direction (ascending and descending) as you go. Swap out student volunteers after each cycle to keep things fresh.
Example 4. Visualizing the number of half steps between D# and Bb using a slinky.
Students also have access to the following diagram.
Example 5. Interval qualities based on half-step manipulations.
Some caveats
I admit I enjoy the chaotic nature of this activity. My Theory 1 class meets at 7:30a on Tuesday and Thursday, which means students are usually dragging when they cross the threshold. The mere presence of the slinky, the stands, and the tape on the stage tends to perk them up.
There's also a degree of unexpected variability that occurs with this lesson. One time the student volunteers produced minor 2nd between E and F, only to then add a sharp to E and a flat to F. At the time this caught me off guard. I really had to think for a second: they had just created a doubly diminished second. This was difficult to explain to the class! The moral here is be prepared to describe some weird intervals if you give students complete agency to assign note names and accidentals. To rein in the chaos, you may choose to start with some instructor-prescribed intervals.
During the lesson, I typically only refer to the note names and write them on the board as needed. Other instructors may prefer to also incorporate staff notation into the activity. It certainly makes it easier to literally see how the generic interval quality, a sixth in our present case, does not change when we add accidentals to the top and bottom notes.
Fin
I hope you found this lesson interesting! If you end up doing it in your class, I'd love to hear about it! You can shoot me an email at sheanicholasj at gmail dot com.
I also plan to upload a short video of this lesson in action once I edit it down.
Cheers,
Nick