The Science of Sound

Here in the Seattle area, we are beginning a period of 6 weeks with no school. This post is my first-pass at a do-at-home session of my Family Inventors’ Lab and Discovery Science Lab. It’s intended to provide hands-on science activities that are easy for parents to do with kids at home. This one’s a loud one, since we’re new to being home all day with kids… I’ll plan quieter activities for future posts, as we all tire out!

Explore Sound Vibrations

In this video, I briefly demonstrate how sound travels in waves, and how the length of a string affects the sound it makes when it vibrates.

Make Sound Vibration Visible: Build a Chladni plate… First, find a container: a bowl, a pot, an empty can, a big plastic cup… Then, stretch a membrane taut across the top of it: saran wrap, a balloon, other plastic. Tape or rubber band the membrane so it is taut. Put your container next to, or on top of a speaker. Sprinkle a little salt or a few grains of rice on top. Now start playing music over the speaker, and see what happens!

You can find the whole tutorial here. If you have a device your child can use effectively to choose different music to play, you could let them explore this for quite a while, seeing how the salt responds to all different kinds of music. If you’re really lucky, your child will become captivated by this activity and you’ll be able to get some work done!

Note: if you put half and half in your coffee or tea, you may notice that when it cools a bit, a skin forms on the top – you can also see vibrations of music in that! (This fact often distracts me when I’m working at Starbucks. :-))

Seeing Vibrations on Instruments

If you happen to have a stringed instrument or a drum or a singing bowl for meditation in your house, get it out, and show your child what happens when  you play it. Help them notice that the instrument vibrates when it’s making noise. Faster vibrations mean a higher pitch, slower vibrations are lower. You can reduce the volume by dampening the vibration. If you don’t have an instrument, click on those links above to see videos.

Seeing Vibrations with Rulers and Rubber Bands

When your kid wanders over to your desk to distract you from your Work at Home day, try this: Place a ruler (metal, wood, or plastic) on the edge of a table, with an inch or two hanging off. “Pluck” it by pushing down and releasing. Then move it so 4 inches hang out and pluck, then 8 inches. Ask your child if they notice the difference in sound. (Here’s a video)  Make a musical instrument with rubber bands (see below) and have your child notice that they make different sounds depending on how narrow or wide the band is and how tightly stretched it is. (Here’s a video with a related experiment.)

ruler

Make an Ear Guitar / Telephone

Take 2 plastic cups or yogurt containers or 2 cans – poke holes in bottom, run string between them (tie knots in the ends of the string so they don’t slip through the hole). Two people stand as far apart as they can, so the string is taut, and take turns talking and listening. Try plucking the string like a guitar and listening. Notice how the vibration travels through the string. More details from Scientific American or Teach Engineering.

Explore Sound Vibrations with a Hanger

Tie two strings on the bottom corners of a wire hanger. Wrap those strings around your index fingers. Place those on your ear so the strings are touching your ear. Stand near a table or wall, and let the hanger swing so it bangs into the table or wall. Then listen to the sound vibrations. (Here’s a video of this.)

Listen through walls

If you need your child out of a room while you’re on a Zoom call: Send them to another room where they can use a glass on the wall to listen to noises in another room. Learn more here.

Listen Closely

What’s that sound?

This one’s super easy. Find an opaque container – a shoebox or whatever. Put an object inside. Shake it and have  your child guess what it is. (If you want, you could sing a song: “what’s in the blue box, the blue box, the blue box, what’s in the blue box, I don’t know.. let’s find out.”) Challenge them to go find a mystery object in the house to put in to challenge you. When they bring it back, you guess what it is, then tell them to put it away exactly where they found it and then find a new item. If you’re really lucky, this game might give you a few minutes to get some work done while they’re off searching for new items!

Match the shaker egg

Sorry, this one takes a little more effort to set up… Find a collection of opaque containers (like yogurt containers or easter eggs.) Fill them with items like dice, pennies, beads, salt, and so on. Make two of each filling. Kids have to shake the containers and find the matching ones.

Sound Symphony

Watch this Sid the Science Kid video (4 minutes), then do the experiment. (Gather a collection of plastic items, a collection of wood items, and a collection of metal items and have them bang them together to hear how different materials have different sound qualities. Or just let your kids rummage through your kitchen cabinets and try things out.)

Musical Instrument Exploration

If you have instruments of any kind at home, now’s the chance to let your child experiment with them. Let them freely explore for a while, making all the noise they want, to discover the properties of the instrument. Every once in a while, drop in a new nugget of information, or a new way to play the instrument to get a high note vs. a low notes, or to adjust the volume, or enhance or dampen the vibrations to change the sound.

Decibel Meter

You could explain to your children that volume is measured in decibels. A whisper is 30 decibels. A loud yell is 85. A jet engine is 140. You could download a decibel meter app onto your phone or tablet, and let them measure the sounds around them. A caution: the thing they’re most likely to do is YELL REALLY LOUD to see how many decibels they can produce.

What if your sense of hearing didn’t work?

Have them try on noise-cancelling headphones (if you don’t have those, even regular headphones or earmuffs will muffle sound) or ear plugs and see how differently they experience the world. (This can pair well with the above activities. 🙂 )

Learning about Earswhoseears

Guess Whose Ears?

Show your child these pictures: PDF. Have them guess what animals they see. Talk about the different shapes of ears and guess reasons why they evolved differently. (It’s OK if you don’t know… you can guess. Here’s a quick slideshow which might give you some hints.)

Make New Ears

Roll one piece of paper into a cone, with just a small opening at one end. Try holding that opening near (not in) your ear canal and listening through the ear trumpet. How do things sound different? Then turn the cone around, so the small opening is facing a sound, and the wide open end is over your ear. How is that different? Now use a paper plate (or a piece of paper). Flop it over your ear like an elephant ear. How is that different? Cut a slash in the plate or paper so you can curl it up like a deer ear. Cup that around your ear. How is that different? Read more details at Scientific American or Exploratorium.

cone cone2

Make a Musical Instrument

Craft Stick Harmonicas

I got this idea from Frugal Fun for Boys and there are also full instructions on the Exploratorium’s Science Snacks page. I LOVE this project!

Take a big WIDE rubber band, wrap it around a jumbo craft stick from one end to the other. Take a one inch piece of plastic straw, and put it under the rubber band, about a third of the way from one end. Put another craft stick on top of this, and wrap one pair of ends together with a skinny rubber band. Then put another straw on top of that wide rubber band (i.e. between it and craft stick #2) about a third of the way from the other end, and  rubber band the other end together. Put it up to your mouth and blow. (Blow… don’t hum.)

Make a Rubber Band Instrument

  • Stretch rubber bands around any margarine container or yogurt container or box. Strum across the top – the container acts as a sound box.
  • Cut a hole in a box (or use a Kleenex box that already has a hole in it). Stretch rubber bands around it and strum over the hole (like a guitar). If you want to get fancy, tuck a pencil under the bands to act like a guitar bridge. [You can make these into guitars if you want a more elaborate end product. Learn how here.]
  • Make a super cute mini banjo with rubber bands, a lid and a craft stick.

Make a straw whistle

As described on Allen Centre’s website and Crafts U Print. Or this cool water whistle from Steve Spangler Science.

This video also shows a fun noisemaker to make with a plastic cup and a string.

Books (and Videos) about Sound

Sounds All Around by Wendy Pfeffer, illustrated by Anna Chernyshova. I made a video of Sounds All Around for my students, to accompany our Zoom online class.

My Discovery Lab had just finished a session on anatomy / organs, where we did things like dissect a cow eye, and a brain. So, when I read the book to them, I interspersed it with two video clips: One called How Do We Sing that talks about how our larynx (voice box) works, and one called How Your Ear Works.

Meet the Orchestra by Ann Hayes. I made a video of Meet the Orchestra. This book, with great animal illustrations by Karmen Thompson introduces all of the instruments. I have inserted sound clips into the narration, so children can hear samples of what each instrument sounds like. (It also talks about how larger instruments play deeper notes, which ties into what we’ve learned in our hands-on activities.) It includes an excerpt from the 1812 overture by the Boston Pops.

The Listening Walk. Here’s someone else’s Video of it. Your child could watch the 7 minute video, and then you could go on a silent listening walk together.

Polar Bear, Polar Bear, What Do You Hear? – great sing-songy, rhyming text for kids to chant along with, where they meet a roaring lion, snorting hippo, hissing snake, and more. 4 minute Video.

Note the links to the books are Amazon Affiliate links and I get a small referral fee if you click through and make a purchase on Amazon.

Listening Games to Play

Copy the Rhythm

Clap out a rhythm, or tap out a rhythm. Ask them to copy you. You can also add sound effect words to help them remember the rhythm: Clap-tap-tap-tap. Clap-lap-clap-lap. Titi-titi-TA-TA. Or whatever! You can also sing note patterns and ask them to copy.

Count the Beans

Take a metal dish or pot and some dry beans. Have the child close their eyes.  Drop one bean, then two beans in quick succession. Ask how many beans you dropped. Continue with a variety of patterns, up to several beans.

Silly sound game:

Ask your child to make a sound with their mouth (whistle, hum, blow a raspberry, click tongue, and so on) or hands (clap, snap, clap legs, etc.) You copy it. Then you make a sound for them to copy.

What’s that sound?

Put your kid on YouTube for a while. (I’m officially declaring that when kids aren’t in school for six weeks straight, we can be a little lax about our minimal screen time rules!!) Play sound recordings and see if kids can guess the sound. Here’s a couple good options – just search YouTube for more: www.youtube.com/watch?v=h0Kp_J9kvNM or www.youtube.com/watch?v=IbXbDw_THso or https://www.youtube.com/watch?v=n1m4h79JZso or https://www.youtube.com/watch?v=pbxFOxz9c1g 

If you have more fun science of sound ideas, put them in the comments!

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