For the first program of our Fall 2014 season, I wanted to give our G3 scientists some activities that let them really go wild (after all, starting up school and homework after a lovely summer holiday can be pretty tough stuff!). And what is more fun than creating a lot of really obnoxiously loud noises? :)
SOUND is a very fun subject to study, especially since I have so many new faces in my G3 programs this season. I started us off with some brief descriptions of the nature of sound and how sound waves work:
- When objects vibrate, the vibrations are projected into the air and create sound waves.
- The sound waves are composed of tiny particles called atoms and the molecules that make up air.
- Even though you cannot see sound waves with the naked eye, you can often feel sound vibrations. [If you're looking to explore this further, how about testing out your very own "sound gun" at home? Trust me, it's a blast! :) ]
And most of the scientists successfully answered all of my tricky true and false questions. From the series of questions, we learned a lot of cool facts about sound:
- Outer space is the only truly silent place in our world…because there is no air to help distribute the sound waves.
- Sound vibrations can be carried through more than just air – they can also move through water, woods, metals, and plastics. As an example, Ludwig van Beethoven (the famous composer who was deaf) would often hold a long wooden stick in his teeth, resting the other end on a piano wire. When he played the piano, the vibrations from the piano wire would travel through the stick, through his teeth, through his skull bone, and then directly to his inner ear where he could make sense of the sounds.
- Snakes have no ears, but a bone inside a snake’s head picks up vibrations from the ground.
Did you know that owls are a bit lopsided? They have one ear slightly lower than the other so that they always have one ear a little closer to sounds on the ground where they look for their food/prey. [And as one of our G3 scientists pointed out, the higher ear is closer to sounds from above where predators might approach the owl...]
- When you put a sea shell up to your ear, you are not actually hearing the ocean. The shell ispicking up vibrations from all of the sounds occurring around you, and those sounds are making the air inside the shell vibrate and carry sound to your ear.
- If you ever hear someone’s stomach growling very loudly, you can say to them, “Your borborygmi is quite loud!” Borborygmi is the fancy scientific term used to describe the process that creates a growling stomach.
And I even found some cool examples of record-breaking sounds to share with our group:
The loudest natural sound in recorded history is still the volcanic eruption on the island of Krakatoa that occurred on August 27, 1883. The sound could be heard (and felt) 3,000 miles away!
- The pistol shrimp, only 2 inches long, can eject a powerful jet of water traveling at over 60 mph from it’s one over-sized claw. The snapping sound itself reaches 218 decibels (your eardrum ruptures at 150 decibels). And at the moment the jet of water explodes from the claw, portions of the stream can reach temperatures as hot as the sun!
- The loudest animal in the world, relative to size, is the water boatman.
- The loudest mammal is the blue whale; the loudest land mammal is the howler monkey; the loudest amphibian is the croqui frog; the loudest bird is the oilbird. [Source: National Geographic]
- Japan holds the world record for the most Theremin instruments playing in unison. What’s a Theremin? Check out the video below to find out…
But we never do just discussions in our G3 programs…we’re scientists after all! So I had a full series of small experiments for us to do, to help us explore sound in a variety of ways.
Experiment #1: Humming Hangers
This experiment never fails to impress! There are many sites that describe how to perform this experiment. It is a very simple experiment, but one with a very cool pay-off. You simply tie a piece of string or yarn (about 1-2 feet long) to each end of a metal clothes hanger. STEP ONE: Swing the hanger against a table or other solid object. What sound do you hear? STEP TWO: With the strings wrapped once around each of your index fingers, put your fingers in your ears and lean forward to swing the hanger against the solid object again. What sound do you hear now? RESULT: The first sound should be a light dinging noise; the second sound should be almost like a loud gong. ANSWER: With the second attempt, you are giving sound a more direct, quicker path to your inner ear…for a much louder, and more accurate, representation of the sound created.
Experiment #2: Visualizing Vibrations
- Paper towel tubes
- Balloons (any kind, any color)
- Small mirrors, about 1 to 2″ square (I got packs of 25 small square mirrors at Michael’s Craft Store)
- Scotch tape
This experiment gave us a handy way to see sound vibrations just using our eyes, though we needed to play around with the procedure to get the best results. All you need is a recycled paper towel tube [some versions use a tin can with both ends removed], a balloon, and a small square mirror. You cut the balloon in half (you really only need enough of the top of the balloon to stretch across the opening of the paper towel tube – try to get as flat a surface as possible). Once the balloon is stretched across one end of the tube, you can hold it in place with pieces of scotch tape. [NOTE 1: most procedures suggest holding the balloon in place with a rubber band. We learned that paper towel tubes are not made as firmly as they used to be (probably due to recycling), so they were collapsing in on themselves when we wrapped rubber bands around the ends. The scotch tape worked much better.] You then tape a small square of mirror to the center of the balloon (by putting a small roll of tape on the center of the balloon end, and then just placing the mirror on top of the tape roll), making sure the mirror doesn’t touch the tube itself. You then ask a partner to point a flashlight directly at the mirror. The light reflects off the mirror onto the wall in front of you. When you speak into the tube or make a noise, the vibrations caused by your voice will cause the light waves to vibrate as well. Now you can actually SEE sound vibrations! [NOTE 2: My scientists and I had the most difficulty with this experiment. There were varying degrees of success depending on how the flashlights were held, how firmly or loosely the mirror was attached to the stretched balloon, and how taught or loose the balloon surface was on the tube. This experiment definitely requires a little hands-on love from instructors and a decent amount of time to let kids work out the hiccups with their partners.]
*Experiment #3: Sound Sandwiches
The last time I did SOUND with my G3 scientists, we created Super Easy Noise Makers. I wanted to try something a little different this time around, and I definitely found a project that was equally as noisy, satisfying, and pretty much guaranteed to succeed for all! I believe this project, hands down, was our scientists’ favorite of the day (though several kids were still in awe of the cool result from the Humming Hangers – I actually sent the kids home with the wire hangers in case they only had plastic ones at home).
- Craft sticks, large and small (I used colorful ones just for some pizzazz)
- Rubber bands of various sizes (I used size 84 with the large sticks though this was probably a tad too big, and I used a standard home office rubber band for the small sticks; basically, you want to make sure that the rubber band will wrap flat around the sticks but will not completely cover the sticks…you should see a margin of the stick surrounding the rubber band on all sides)
- Drinking straws, cut up into 2″ pieces
You can click on the experiment title above to see a video demonstration of exactly how to assemble the sound sandwiches. They were fantastically fun! We made the large ones, the small ones, and even some triple and quadruple stacked sound sandwiches! Our scientists had a lot of fun imitating what they imagined old men laughing might sound like, and I’m pretty sure my large sound sandwich sounded like a dying animal (hahaha) :)
As always, my scientists went home with plates full of their projects and even a few extra supplies to help them recreate some sound sandwiches at home with younger siblings. I love how the G3 crew often leaves my program excited to share their knowledge with younger science lovers at home.
Next week be sure to check out the fun we’ll have playing with wind!…