Sound Vibrations and Frequencies

Researching about sound, sound vibrations and soundwaves.
Harshini Patil
Grade 7


What Is Sound, Soundwave, and Sound Frequency?

Question/Problem: What is the scientific definition of sound, how is the sound created, what are soundwaves and sound frequencies, and how do human beings process soundwaves through their brain?  


Hypothesis: If a sound is created by the vibration of an object, then a sound is a form of kinetic energy because kinetic energy is the movement of matter that depends on mass and motion, therefore, because particles are matter being moved when something vibrates, the particles gain kinetic energy and sound, soundwaves, and sound frequencies are being produced.    


What Is Sound?                                                             Sound Waves | PASCO

Sound, just like electricity, is a form of both, kinetic and potential energy (mechanical energy). Sound is a wave or vibration that can travel through solid, liquid, and gas. Evidently, Sound is an energy that can be heard and made, it is created by a mechanical movement that is produced when particles vibrate. As human beings, we call sound by a lot of different names, for example:

  • Strident or undesirable sound is called noise                                                                                                
  • Instrumental and congenial sound is called music
  • The sound made by someone and is used to communicate with each other is called language       

No matter what type of sound is made or what made the sound, they are all produced the same way: Through vibrations

How is Sound Made?                                                  Audiology Worldnews

Sound is a wave or a vibration made when an object moves in any way. The vibration of the object becomes the source of a "domino effect", as the particles from the surrounding medium (solid, liquid, or gas) start vibrating and bumping into each other and causing other particles to start vibrating too. This cycle continues until the vibration reaches our ears, which can detect the vibrations and the ears send signals to our brain. When these vibrations are transferred from particle to particle, sound waves are being created.


                                                                                        Air particles bumping into each other

                                                        Sound Waves - Teach Me Audio 

The Three Types of Sound:

  1. Anthrophony: The word "anthrophony" comes from a combination of two words which are "anthro" which means human and "phon" which means sound, therefore, anthrophony is the sound made by humans and their creations such as musical instruments, machines, and even language. 
  2. Geophony: Geophony is the sound made by the earth and the environment around us, it comes from the word "geo" which in Greek, means "earth-related". Examples of geophony are rain, thunder, and waves. 
  3. Biophony: The sound made by non-human animals in a given environment. Examples of biophony are chirping birds, croaking frogs, and roaring lions. 



Soundwaves are what is created when particles create an ongoing and consistent sound effect that travels in all directions. It is a horizontal wave that runs lengthwise and can travel at 761 mph or 1100 feet/second. This continued motion created, is called a soundwave. Soundwaves have different shapes depending on the pitch or frequency of the sound. There are two different types of soundwaves:

  1. Transverse Waves: A disturbance moves perpendicular (90 degrees) to the direction of the wave.  

Transverse and longitudinal waves review (article) | Khan Academy

      2. Longitudinal Waves: The disturbance moves in the same direction (parallel)  as the direction of the wave. 


The section where the particles bump against one another is called compression, when particles are vibrating however not bumping into each other, it is called a rarefaction. The highest expanse of the wave is called the crest and the upright length between the crest and the trough of the soundwave is referred to as the wave height. The amount of space between crests or troughs is called the wavelength and can affect the wave's frequency. The baseline is in the middle of the wavelength and is between the crest and the trough of the soundwave, the measurement from the trough or crest to the baseline is called the amplitude.     

35 Label Of A Wave - Labels Database 2020 (The baseline is the red line running across the middle)

Sound Frequency: Sound frequencies are measures in hertz (unit) and can have widely ranged pitches, or volume, depending on how it is made. A sound frequency is the number of times a sound wave repeats itself per second. The lower the waves, the lower the times the wave fluctuates and vibrates, the higher the wave, there is more vibrating and the wave amplitude is also higher. The lower the wave fluctuation, the lower the sound, and the higher the sound wave fluctuation, the higher the sound. Therefore, when there are a certain number of waves, passing over a fixed place over a given number of times, the frequency is high, and we hear low frequency sounds when the number of waves becomes less. Research shows that human beings can hear sound frequencies from 20 to 20,000 hertz. Frequencies that are lower than 20 Hz are called infrasound, and frequencies that are higher than 20.000 Hz is called ultrasound

Bass Traps 300mm High Performance Studio Acoustic Foam & Corner Cubes | eBay  

How do Humans Detect Sound? When soundwaves make their way through our ear canal (the tube that leads to the eardrums), the vibrations make our eardrums vibrate too, these vibrations continue until they reach the other parts of our ears (malleus, stapes, and incus). These parts of our ears send a signal to the cochlea, the part of our ear that has the job of sending signs and indicators to our brains about familiar wave sounds (languages) which then converts those sounds into meanings that we can comprehend. As mentioned before, the eardrums are only capable of detecting frequencies from 20 Hz to 20,000 Hz, while other animals in the world are capable of detecting much higher and lower frequencies than us. 

                                                                    Understanding how the ear works - Hearing Link  

                                               Hearing Range of Frequencies (GA_M-SND20) - YouTube


Fun Facts:

- Sound travels faster in water than through any other medium

- There is no sound in space because there are no particles to bump into (it is a vacuum)

- The loudness of sound is described as volume, and we use decibels (DB) to quantify the volume

- Sound waves can bend around objects and be reflected off of materials as well

- Dogs can hear a higher frequency than humans, allowing them to hear things that we can't

- Light travels faster than sound, this is why on rainy days you might be able to see the lightning before the thunder 

- Human baby cries can be louder than car horns (about 115 decibels)



                                                             If sound waves... Should I wave back?? - Futurama Fry | Make a Meme

                                                                                                     *** Thank you***

Harshini Patil, Fairview School, Mrs.Shoults 

Grade. 7


Application: Where Would This Information Be Useful In Life?

Scientists use sound frequency in a lot of different ways, for example, biophony scientists use gadgets and mechanics to determine which animals are living in a certain environment by detecting the noise they make. In the Amazon forest, many microscopic species that cannot be seen very well have been discovered using the sound frequency they make. Scientists can find out whether or not a species is still living there, has gone extinct, or if the breed is thriving in the environment by comparing the pitch or lack of frequency about every once a year. This way, through a period of time, they can figure out how the species has been living in its habitat. 

In the military, the army can use different frequencies through any medium to communicate with their allies. They can send code messages without anybody noticing or any sort of social communication. Even if the enemies detect the frequency, they will not be able to decode the messages.  




Conclusion:  In conclusion, a sound is a vibration that is made when particles vibrate and bump into each other, sound can travel through any medium that contains particles and has the capability of bumping into each other. Soundwaves are the motion in which particles continue to intersect one another and sound frequency how many times several soundwaves pass through a place at a given time. My hypothesis was incorrect because a sound is not a form of mechanical energy, which is a type of energy that is made when both potential and kinetic energy is possessed in an object. Soundwaves are very similar to sound because sound waves are created when sound vibrations occur. They are created when particles continue bumping into one another and the sound travels further and further. 






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I would like to thank my family for supporting and helping me with my project whenever I needed help and encouragement. When I had trouble figuring a concept out, they would try to help me as much as possible.

I would also like to acknowledge my science teacher as well because she really helped me understand and clarify instructions I did not understand. She gave me very useful feedback and made sure my work was up to the best of my ability. 


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