Science project

Air & Sound

Research Questions:

  • Why do we take a deep breath before yelling/screaming?
  • How do you increase the loudness of an instrument?
  • What is the relationship between air pressure and sound level?
  • How do megaphones/speaking trumpets work to amplify sound?

Have you ever been told to turn your music or the television volume down? In most cases it is to accommodate others, but exposure to prolonged loud noises can affect our hearing. Loudness is measured in decibels (dB). The decibel is a ratio between the loudness of a sound relative to a reference point, usually the sound pressure level of air. The human hearing range, with respect to loudness, is between 0 to greater than 130dB. Breathing is around 10dB and normal conversations range from 40-60dB. At around 85dB the chances of noise induced hearing loss increases. Prolonged exposure to sounds such as a motorcycle engine or kitchen blender can affect your perceived range of loudness and frequency (pitch). Some sounds can even produce pain such as an ambulance siren, around 130dB. In this experiment students will produce sounds and measure loudness in decibels. By examining the force it requires to create sounds of varying loudness students can then find the relationship between air pressure and loudness.


  • Sound-level meter (found at electronic/computer stores or a physics laboratory)
  • Musical instrument – woodwind or brass
  • Megaphone/ speaking trumpet – construct with poster board

Experimental Procedure:

  1. Find a quite room to perform your sound level meter readings. Setup your meter so that the microphone is free from any obstruction. Produce all your sounds approximately 2 meters from the microphone. Setup a chair or marker so you can remember that position. Record the sound pressure levels in dB for each of your sounds.
  2. Speak at your normal volume.
  3. Speak at your normal volume but use a megaphone.
  4. Scream.
  5. Scream with a megaphone
  6. Whisper.
  7. Whisper with a megaphone
  8. Play a note on the instrument of your choice at a moderately soft loudness (mp). What kind of breath do you need to take?
  9. Play that same note at a loud level (f). What kind of breath do you need to take?
  10. From your data figure out the relationship between air pressure and sound level.

Terms/Concepts: Sound wave; Decibel; Sound pressure level; Amplitude; Musical dynamics – piano, forte, mezzo-piano, mezzo-forte, pianissimo, fortissimo.


Decibel Exposure Time Guidelines

Author: Melissa Bautista
Disclaimer and Safety Precautions provides the Science Fair Project Ideas for informational purposes only. does not make any guarantee or representation regarding the Science Fair Project Ideas and is not responsible or liable for any loss or damage, directly or indirectly, caused by your use of such information. By accessing the Science Fair Project Ideas, you waive and renounce any claims against that arise thereof. In addition, your access to's website and Science Fair Project Ideas is covered by's Privacy Policy and site Terms of Use, which include limitations on's liability.

Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state's handbook of Science Safety.

Add to collection

Create new collection

Create new collection

New Collection


New Collection>

0 items

How likely are you to recommend to your friends and colleagues?

Not at all likely
Extremely likely

What could we do to improve

Please note: Use the Contact Us link at the bottom of our website for account-specific questions or issues.

What would make you love

What is your favorite part about