Key concepts
Do you enjoy singing holiday songs at school—or with friends or family? Singing can be a fun tradition, especially at this time of year. But have you noticed that different people tend to sing different parts of a song—or sing in different octaves? Have you ever wondered what the highest note is that you can sing? How about the lowest? Do you think males and females can reach most of the same notes? How about children and adults? In this "note"-worthy science activity, you'll get to answer some of these questions!
Have you ever started singing a song, and then realized a little way into the melody that the notes were too high or too low for you to sing well? If so, the song was outside of your vocal range. A person's vocal range consists of all the notes between the lowest and highest notes 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. When air is expelled from a person's lungs, it's carried out of the body through a tube called the trachea (or windpipe) in the throat. In the trachea, the air passes through the larynx (or voice box), which contains folds of tissue called the vocal cords. The vocal cords vibrate as air passes by them, and this vibration creates sound. If you place your fingers at the base of your throat as you sing or talk, you might be able to faintly feel these vibrations.
The pitch of the sound a person makes is determined by several factors, including the size and tension of his or her vocal cords. By changing some factors, people can produce different pitches, or notes. 

  • Piano, keyboard or a virtual piano online (such as this virtual piano keyboard).
  • Volunteers (at least three). If you want to compare how age affects vocal range, you will want some adults age 21 or older and some children age 9 or younger (all of the same gender to make comparisons easier). If you want to investigate how gender affects vocal range, be sure to include both males and females (all of the same age range).
  • Make sure you are familiar with the names and locations of the notes on the piano. Specifically, make sure you can find Middle C. Middle C is often called C4 because it is the fourth C key on a standard piano. If you do not know which key is Middle C (C4), you will need somebody who can show you or you can use this virtual piano keyboard, which has labeled keys. Can you find Middle C?
  • There are seven notes on a piano keyboard (A, B, C, D, E, F and G) that are repeated over. The white keys on the piano represent these notes. Can you identify these notes on the piano? (The black keys are smaller shifts in pitch, either sharps or flats, and will not be used in this activity.)
  • Familiarize yourself with the other notes on the keyboard. 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 (the fifth C key on a standard piano) is called D5, and so on. The keys to the left of C4 are lower in pitch. The B to the left of C4 is called B3, the B to the left of C3 is called B2, and so on. Can you identify C3, C4 and C5, and the notes in between these ones?
  • Get your first volunteer ready, and play C4 on the piano, keyboard or virtual piano keyboard. Can the volunteer sing the note back to you? If the volunteer can comfortably sing the note, then it is in his or her vocal range. (For this activity to accurately map vocal ranges, the volunteer has to actually sound like he or she is singing; if the "singing" sounds like grunting, growling, screeching or squeaking, then it does not count and the note is not in the volunteer's vocal range.)
  • 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. If the volunteer finds it helpful, he or she can sing "do," "re," "mi," "fa," "so," "la," "ti," "do," when singing increasingly higher-pitched notes (such as for singing the notes C4, D4, E4, F4, G4, A4, B4 and then C5). What is the highest-pitched note that the volunteer can sing? (This is the top of the volunteer's vocal range.)
  • To find the bottom of the volunteer's vocal range, go back to C4 and keep playing increasingly lower-pitched notes (to the left of C4) and have the volunteer sing each note back to you until you come to a note that is no longer comfortable for him or her to sing. If the volunteer finds it helpful, he or she can sing "do," "ti," "la," "so," "fa," "mi," "re," "do," when singing increasingly lower-pitched notes (such as for singing the notes C4, B3, A3, G3, F3, E3, D3 and then C3). What is the lowest-pitched note that the volunteer can sing? (This is the bottom of the volunteer's vocal range.)
  • Repeat this process with each of the other volunteers. What is the vocal range for each volunteer?
  • How do the vocal ranges of male and female children compare? What about male and female adults, and adults compared to children?
  • Extra: You could do this activity again but this time use at least 20 volunteers as follows: 10 adults (age 21 or older, including five males and five females) and 10 children (age 9 or younger, including five males and five females). How does age and gender appear to affect a person's vocal range?
  • Extra: Investigate several different musical instruments and their musical ranges. How does the human vocal range, which you explored in this activity, compare to the musical range of other instruments?
  • Extra: Do some research into the classification of vocal ranges for choirs (e.g., soprano, alto, baritone, etc.). You can use the resources in the "More to explore" section to help you do this. What ranges do your volunteers belong to? Which basic choral ranges are easiest to fill? Which are the hardest to fill?

Observations and results
Did you find that children typically have the highest vocal ranges (regardless of gender), and adult men typically have the lowest?
One thing a person cannot control is the length of his or her vocal cords, which affects the pitch of sound a person makes when singing. Vocal cord size is similar in young males and young females, which is why children—boys and girls—have a similar vocal range. (This is from about A3 to G5.) But as children go through puberty, their vocal cords grow longer, giving adults typically lower vocal ranges than children. 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. Consequently, singing voices for women are usually a little higher than for men, with the highest female voice (soprano) reaching C6 and the lowest one (contralto) going down to E3, while the highest male voice (countertenor, typically in falsetto) may hit E5, and the lowest one (bass) can drop down to E2.
More to explore
Why Are Human Voices Different?, from Pitara
Your Changing Voice, from KidsHealth
Comparing Vocal Ranges: How High and Low Can You Go?, from Science Buddies
Science Activities for All Ages!, from Science Buddies

This activity brought to you in partnership with Science Buddies