G3 Program 18: SOUND!

For our final G3 program of 2012, I thought it was time to get a little noisy and tackle the topic of SOUND. We even had some special guests visit TRACK A on December 6th to take part in some of our fun:  State Representative Mary G. Fritz (Democrat) and Steve Senator Joe Markley (Republican).

As luck would have it, several of our G3 scientists had just learned about ‘sound’ at school, so they had a head start on our topic of the day. And they were all very well-versed on the subject. I started our program by briefly describing 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…(as seen in the demonstration of our very own “sound cannon” below)…


Ludwig van Beethoven

Ludwig van Beethoven

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.
  • When you put a sea shell up to your ear, you are not actually hearing the ocean. The shell is
    Lithograph of Krakatoa Eruption in 1883

    Lithograph of Krakatoa Eruption in 1883

    picking 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: http://www.nationalgeographic.com]

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

There are many sites that describe how to perform this experiment. This is a very simple experiment, but one with a very cool pay-off. You simply tie a piece of string (about 1-2 feet long) to each end of a metal clothes hanger. You swing the hanger against a table or other solid object. What sound do you hear? 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

Busy at work...

Busy at work…

This experiment gave us a handy way to see sound vibrations just using our eyes. 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). Once the balloon is stretched across one end of the tube, you can hold it in place with a rubber band. You then tape a small square of mirror to the center of the balloon, 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!

*Experiment #3:  Super Easy Noise Makers

I believe this project, hands down, was our scientists’ favorite. With a few simple steps, you can convert a standard plastic drinking straw into a crazy-loud noise maker! We had bendy straws on hand, so first we cut off the bendy end of our straws. We then flattened one end of the straw, cutting off the two corners at the tip. Essentially, you are creating the equivalent of a reed instrument, like a clarinet or an oboe. We then turned a recycled piece of paper into a giant funnel and taped it the opposite (non-cut) end of the straw. The final step – blow! It was the final step that was the most challenging. Some scientists got the knack of it right away – others need the help of their fellow scientists to figure out the best method to make the noise. TIP 1: Make sure the entire cut end of the straw is inside your mouth when you blow. TIP 2: Unlike the way you blow with a recorder, with this straw you need to purse your lips together a bit and focus your blowing.


Experiment #4:  Buzzing Noise Maker

This noise maker doesn’t create as loud a noise as the straw, but it has a lot of flare since you get to swing it around in the air by its string. Full directions can be found on the Steve Spangler science web site by clicking the experiment title above. This was probably the trickiest project for our scientists. You need to be careful with how you put the pieces together. And the size of the rubber band is directly related to the quality of the sound you produce…since the noise is created by the vibrations of the rubber band. We had large rubber bands that were too tight to produce much vibration. Likewise we had smaller rubber bands that didn’t vibrate enough to create much sound. However, some of our scientists came up with the clever idea of putting two of our smaller rubber bands side-by-side on the craft stick, and that definitely led to a better sound.

2012 has been a really fun year for me, and hopefully for all of my G3 scientists! I’ll have some really great projects and experiments ready for us in 2013. But for now…

H A P P Y   H O L I D A Y S !!!

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