![]() Take the phone into different rooms, a library or to a playground or park. Try measuring background noise levels in different locations.How does the decibel level change as you get farther away? Start out with the phone right next to the source and then slowly walk away. Try to find a relatively constant sound such as a running faucet or a person humming. Find out how distance from the sound source affects the sound level.How do all the different sounds compare? Which ones are the loudest? You can also try running some appliances such as a microwave or vacuum. There are plenty of other everyday sounds you can try as well-for instance, running a faucet or a clicking light switch. This can be as simple as clapping your hands or knocking on a door. Is everyone’s “normal” voice the same decibel level? Who can yell the loudest? If there are other people around, try measuring their voices as well.Does the whisper even register or is it drowned out by the background noise? How loud is your yell? You can also try other sounds such as whistling or humming. Try whispering, talking and even yelling at the phone. What is the decibel level? Does it fluctuate with background noises, such as a car driving by or a bird chirping? Put the phone down, sit perfectly still and hold your breath. Determine the level of background noise.Make sure the app is working: Talk at a normal volume, and you should see the numbers fluctuate. Some apps will just display a number on the screen whereas others will display a meter or a graph. There are plenty of free options available, but some apps may have ads or in-app purchases enabled. Ask an adult to help you search for a “decibel meter” or “sound meter” app on a smartphone or tablet. ![]() Multiple locations to take the phone (optional).Other people whose voices you can measure (optional).Adult (to help verify and download the app).Smartphone or tablet with internet access and permission to download and install an app.So if you want to explore the sounds of the world around you, all you need is a phone! Modern smartphones, however, (which already contain built-in microphones) can run apps that will display the sound reading in dB directly on the phone's screen. ![]() What does all this have to do with a smartphone? If you wanted to measure sound levels previously, you would have had to buy a stand-alone decibel meter-a device with a microphone and a screen that would display the sound level in dB. Note the loudness of a sound also depends on your distance from the source of the sound (it will get quieter as you get farther away)-so to do a direct comparison of different sounds, you have to keep this distance constant. That’s why hearing protection is recommended for people using equipment such as lawn mowers. Sound levels above 80 dB can cause hearing damage over long periods of time, and sound levels above 120 dB can cause immediate damage. Sound confusing? Don’t worry-here's a list of reference sounds and their approximate decibel levels: Rather, 0 dB is chosen as a reference level at the threshold of human hearing. Zero dB doesn’t mean there is no sound at all. A 40 dB sound is twice as loud as a 30 dB sound, and four times as loud as a 20 dB sound, etcetera. For example, a 30 dB sound is twice as loud as a 20 dB sound. What does that mean? For every increase of 10 dB, the loudness of the sound doubles. The decibel scale is a little unusual because it is logarithmic rather than linear. Sound is measured using a unit called decibels, abbreviated dB. But how do we measure sound? You might describe a sound as “quiet as a whisper” or “louder than a jet engine,” but you probably wouldn’t use a number. ![]() You wouldn’t bat an eye at someone saying they are six feet tall or it’s 70 degrees outside. You’re probably familiar with the units we use to measure everyday quantities, such as length or temperature. How quiet is a library? How loud is that truck roaring by? Try this activity to find out! Please let us know what you think! E-mail with feedback about the use of technology in this-and future-Bring Science Home activities.ĭid you know that you can use a smartphone as a scientific instrument to explore the world around you? Smartphones contain many built-in electronic sensors that can measure phenomena such as sound, light, motion and more! In this activity you’ll use a phone's microphone to examine the loudness of different sounds in your environment. This is our first activity that requires the use of a smartphone or tablet. We recognize technology is now more widely available than it was when we began this series in 2011 and that it can add value to scientific exploration. Editor's Note: We have strived to maintain accessibility in our Bring Science Home activities by limiting the required technology. ![]()
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