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Project Summary

Difficulty	3  –  5
Time required	Short (several days)
Prerequisites	To do this science fair project, you'll either need to know which key is middle C on your piano or keyboard or have a friend or family member show you. See the Experimental Procedure for more details.
Material Availability	This science fair project requires access to a piano or keyboard.
Cost	Very Low (under $20)
Safety	No issues

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Objective

Compare the vocal ranges of people to determine if puberty and gender affect vocal range.

Introduction

Have you ever started singing a song, and then realized a little way into the melody that the notes were either too high or too low for you to sing? If so, the song was outside of your vocal range. A person's vocal range is the lowest and highest notes (along with all the notes in between) that a person can comfortably sing.

To understand what might determine a person's vocal range, it is important to first understand what is happening when a person sings. First, the air is expelled (breathed out) from the lungs. It is carried out of the body through a tube called the trachea, which is part of the throat. On its route through the trachea and out of the mouth, the air passes through the larynx, often also called the voice box. The larynx contains folds of tissue, called the vocal cords. The vocal cords vibrate as air passes through them, and this vibration creates sound. If you place your fingers at the base of your throat and sing or talk, you might be able to faintly feel these vibrations.

Figure 1. This photo of a patient's larynx was taken by a doctor using a small camera attached to a thin tube (called an endoscope) which was put into the patient's mouth and down the throat. Both the trachea and the vocal cords are labeled. (Modified from Samir, 2007.)

The pitch of the sound a person makes is determined by several factors, including the size and tension of the vocal cords, and how fast they vibrate. By changing some of these factors, people can produce different pitches, which means they can sing a variety of notes. But one thing a person can't control is the length of his or her vocal cords. Vocal cord size is similar in young males and females. As children go through puberty, however, their vocal cords grow longer. By the time they're adults, most females have vocal cords that are between 12.5 millimeters (mm) and 17.5 mm long; adult males usually have longer vocal cords, between 17 mm and 25 mm in length (Titze, 2008).

Do you think the difference in vocal cord length between adults and children, and between people of different genders, might affect the vocal range of each group of people? You can find out the answer in this science fair project by comparing the vocal ranges of four different groups of people: male adults, female adults, male children, and female children. Since puberty is a period of time when a person's vocal range may be changing, you'll need to make sure all the people you examine in this science fair project are either done with puberty, or haven't entered puberty yet. For this reason, only gather data from children age 9 or younger, and adults age 21 or older. Who has the highest vocal range? How about the lowest? Get ready to take "note" of the answer!

Terms, Concepts and Questions to Start Background Research

• Vocal range
• Expel
• Lungs
• Trachea
• Larynx or voice box
• Vocal cords
• Pitch
• Puberty
• Gender
• Middle C
• Magnitude

Questions

• What is vocal range?
• How do people produce sounds when they sing?
• Why do musicians need to know their vocal range?

Bibliography

For more information about vocal range, try these websites:

• Wikipedia Contributors. (2008, November 10). Vocal range. Wikipedia: The Free Encyclopedia. Retrieved November 10, 2008, from http://en.wikipedia.org/w/index.php?title=Vocal_range&oldid=250915806
• Vocalist.org.uk. (2008). Vocal Range—Finding Your Keys! Retrieved November 10, 2008, from http://www.vocalist.org.uk/vocal_range_key.html

For more information about middle C and other notes on the piano, try these websites:

• Wikipedia Contributors. (2008, November 12). Middle C. Wikipedia: The Free Encyclopedia. Retrieved November 12, 2008, from http://en.wikipedia.org/w/index.php?title=Middle_C&oldid=246498918
• Bean, K.R. (n.d.). Where's Middle C, and Why Do I Need to Know? or Finding Your Way Around the Keyboard. Retrieved November 12, 2008, from http://www.pianofinders.com/pianomanual/WhereIsMiddleC.htm

These resources provide good information about the biology of singing:

• Titze, I.R. (2008). The human instrument. Scientific American, 298 (1):94-101.
• Kidshealth.org. (2007). Your Changing Voice. Retrieved November 12, 2008, from http://kidshealth.org/kid/grow/boy/changing_voice.html

For help creating graphs, try this website:

• National Center for Education Statistics. (n.d.). Create a Graph. Retrieved October 24, 2008, from http://nces.ed.gov/nceskids/CreateAGraph/default.aspx

Materials and Equipment

• Piano or keyboard; if you do not have your own, see if your school will let you borrow one for this science fair project.
• Volunteers
  1. 10 adults (age 21 or older), 5 male and 5 female
  2. 10 children (age 9 or younger), 5 male and 5 female
• Lab notebook
• Graph paper

Experimental Procedure

Finding and Naming the Notes on a Piano or Keyboard

To start this science fair project, you'll need to be familiar with the names and locations of notes on the piano so that you can both play them, and write down in your lab notebook which ones you are playing.

1. First, find middle C on the piano or keyboard.
   1. If you don't know which key is middle C, you'll need to find a friend, family member, or music teacher who can show you or figure it out using this article about middle C.
   2. There are many different labeling systems for writing middle C. In this science fair project, we'll refer to it as C4 and base the names of all the other notes around that. If you're already familiar with another naming system, it's okay to use the system you already know.
2. There are seven notes—A, B, C, D, E, F, and G—repeated over and over on the keyboard. See Figure 2, below.
   1. The white keys on the piano or keyboard represent these notes, the black keys are smaller shifts in pitch (either sharps or flats) and do not count as new notes in this science fair project. You'll only use the white keys for this experiment.
   2. The keys to the right of C4 are higher in pitch. The D to the right of C4 is called D4, the D to the right of C5 is called D5, and so forth.
   3. The keys to the left of C4 are lower in pitch. The B to the left of C4 is called B4, the B to the left of C3 is called B3, and so forth.

Figure 2. The top diagram shows the placement of the all the different C notes on a full-size keyboard. The bottom diagram shows a close-up with the names of the notes represented by the white keys around middle C. Middle C is highlighted in yellow in both diagrams.

Determining Vocal Range

1. Start by playing C4 on the piano or keyboard. Have the volunteer sing the note back to you. If he or she can comfortably sing the note, then it is in his or her vocal range.
   1. If the volunteer has to strain to reach the note, then it is not in his or her vocal range.
   2. The volunteer has to actually sound like he or she is singing. If the "singing" sounds like grunting, growling, screeching, or squeaking, then it doesn't count and the note is not in the volunteer's vocal range.
2. If the volunteer can sing C4, keep playing increasingly higher-pitched notes (to the right of C4) and have the volunteer sing them back until you reach a note that is no longer comfortable for him or her to sing.
   1. Remember to only use the white keys for this experiment.
   2. Make a data table, like the one below, in your lab notebook. Mark each note that the volunteer can sing with an "X". The highest pitched note that he or she can sing is the top of his or her vocal range. Note: You will probably need to include more notes than the ones shown in the data table below.

3. To find the bottom of the volunteer's vocal range, go back to C4. This time, keep playing increasingly lower-pitched notes (to the left of C4), and have him or her sing each note back to you until you come to a note that is no longer comfortable for him or her to sing.
   1. Remember to mark each note that the volunteer can sing with an "X" in the data table in your lab notebook.
   2. The lowest-pitched note that he or she can sing is the bottom of his or her vocal range.
4. Repeat steps 1–3 of this section for each of the volunteers. In the end, you should have data from a total of 20 people. You can include yourself as one of the volunteers, if you fit into one of the volunteer categories.
   1. You should have data from four categories of people, with five volunteers per category:
      • Male adults, age 21 or older
      • Female adults, age 21 or older
      • Male children, age 9 or younger
      • Female children, age 9 or younger

Analyzing the Data

1. For each category of volunteers, count how many of them were able to reach each note. Make a new data table, like the one below, in your lab notebook, showing the totals.
   1. For example, if all five of the male adults you tested were able to sing C4, write "5" under the C4 column in the "Male adults" row.

2. Using the totals in your data table, make bar graphs showing the number of volunteers who can sing each note. Make one bar graph for each volunteer category, for a total of four graphs.
   1. If you need help graphing, or would like to use the computer to make your graphs the Create a Graph website might be helpful.
3. Compare the four graphs.
   1. How do the vocal ranges of male and female children compare? Are they similar or different?
   2. How do the vocal ranges of male and female adults compare? Is one higher than the other?
   3. Look at just the male graphs. Does age affect vocal range for males? Now look at just the female graphs. Does age affect female vocal range?

Variations

• On average, how many notes are in a person's vocal range? Does gender or puberty affect the magnitude of a person's vocal range? Do trained singers have larger vocal ranges than non-trained singers? Modify the Experimental Procedure above to answer these questions.
• How does the human vocal range compare to the musical range of other instruments? Design an experiment to find out.
• Which choral parts (soprano, alto, baritone, etc.) are easiest to fill? Which are hardest to fill? Determine the choral range of each of your participants to find out the answer! Note: More information about choral ranges can be found in this Wikipedia entry about vocal range.

• For more science project ideas in this area of science, see Music Project Ideas.

Credits

Sandra Slutz, PhD, Science Buddies

Last edit date: 2008-12-12 10:11:00

Career Focus

If you like this project, you might want to think about career opportunities in Music.

Any time you hear music at a concert, a live speech, the police sirens in a TV show, or the six o'clock news you're hearing the work of a sound engineering technician. Sound engineering technicians operate machines and equipment to record, synchronize, mix, or reproduce music, voices, or sound effects in recording studios, sporting arenas, theater productions, or movie and video productions. Learn more about this career: Sound Engineering Technician.