Are sound and noise the same thing?
At a scientific level, sound and noise are technically the same - they are vibrations in the air (or in
water) that we pick up with our ears. The bigger the waves are (their amplitude), the stronger the
vibrations are, and the louder the sound is. However, sound is something that we hear in general.
Noise is something that we can hear, but don’t necessarily want to hear.
How do we measure sound?
Sound is measured in decibels (dB). Decibels are named after the one-and-only Alexander Graham
Bell, scientist and inventor of the telephone.
Did you know?
Alexander Graham Bell was keenly interested in studying sound because both his mother and wife
were deaf.
One way sound is measured is with a sound level meter. This device has a microphone connected to
an electronic circuit and display. It picks up the amount that air particles are being “pushed around,”
which we perceive as sound. These pressures are then translated to electrical signals and displayed as
the sound level, measured in dB. This method is usually best for taking a measurement at one point in
time. In other words, it’s best for measuring an environment that has a constant level of sound and
can be used to see what level of sound someone is exposed to in that area over a day.
Another method is by using a noise dosimeter. This also has a microphone and recorder attached to it,
but is used to record sound levels throughout the day and then averages the total noise someone is
exposed to. This is usually attached near someone’s ear so it can accurately record the level perceived
by the person throughout the day. This is best for measuring environments where sound levels
constantly change and is also measured in dB.
Left: Sound Level Meter and Analyzer (Sensidyne, LP [CC BY-SA 3.0] via Wikimedia Commons). Right:
Noise dosimeter installed on a soldier during training (Public domain image by Pascal Demeuldre
via Wikimedia Commons ).
What sound levels are safe?
In general, sound levels that are below 85 dB are considered to be safe. However, sound levels that
are 85 dB or more are considered dangerous. In fact, the louder the sound, the more quickly it can
cause permanent damage to your ears. For example, listening to a song at 85 dB for 8 hours will
cause permanent damage. But listening to a song at 100 dB can cause permanent damage within 15
minutes!
Decibel levels for some familiar sounds (©Let’s Talk Science using an image from iStock).
In case you are curious, here is a list of sound levels and how quickly these can cause harm. Why does
danger rise more quickly than the number of decibels?
Because when a sound level rises by 10 dB sound pressure goes up ten-fold. However, because our
brains adjust what we hear, it only sounds twice as loud to us.
Sounds don’t have to be damaging to be uncomfortably loud, though. Most people find sounds in the
range of 60-65 dB uncomfortable. The World Health Organization (WHO) suggests that the optimal
sound level in a classroom should be at or below 35 dB.
What are the negative effects of noise?
Noise doesn’t necessarily have to be loud to have an effect on someone’s health. For example, a
squeaky door which keeps opening and closing is not loud, but can be extremely annoying! Some
negative effects of such noise may include:
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You feel more stressed than usual
You heart beats faster than usual
You sweat more than usual
You are unable to sleep well
You get angry or annoyed by the smallest things
You feel anxious and uneasy
In some extreme cases, people who are constantly exposed to stressful noises can end up with
cardiovascular disorders, such as heart attacks or heart disease.
Did you know?
The sound of nails on a chalkboard is on a list of the most annoying sounds in the world!
Often, people feel their quality of life can be affected by noise as well. For example, some people
have a harder time enjoying their backyard because of nearby traffic or overhead aircraft sounds.
What are the positive effects of noise?
Okay, so we have been focused on all the negatives when it comes to noise. But, there are some
positives as well! Music can help you work more efficiently, especially when you’re doing routine or
less difficult tasks.However, studies have shown that music can make it harder for you to work on
more complex tasks, such as learning something new.
Do you think she is listening to music? Why or why not? (image via Pixabay).
In other words, music tends to be more helpful when doing daily chores, but may not be the best idea
when you are trying to solve complex physics problems for homework. The reason for this is when
you are overwhelmed or stressed, extra noise can worsen your stress levels. But, it can still be helpful
in giving you extra focus when you are just reviewing old information.
Let’s do a little recap...
Sound is measured mainly in decibels. You can measure sound at a specific point in time with a sound
level meter or get an average of sound levels over a period of time with a noise dosimeter.
Sounds that are 85 dB or greater can be dangerous and cause long-term damage to your hearing.
Ideally, it is best to listen to sounds less than 85 dB.
Sound can have negative and positive effects depending on the situation and type. Unwanted sounds
(AKA “noise”) which annoy you can lead to a stress response. This can make you anxious and irritable.
When you’re doing complex tasks (like learning new information), noise can make it difficult for you
to focus. However, music can be helpful and make you more creative when doing less difficult tasks. It
may also help you focus on certain routine tasks as well.
Sound is not as simple as you may have thought! As you can see, sound and noise can affect you in
different ways. Who knew listening could be so complex?