Lots of Bots


Ted Beyer, Educational Innovations, Inc.by Ted Beyer

Bots in a Name?

Brushbots, bristlebots, scooterbots, and any other cleverly named bots have been around for years.  You know—the toothbrush head (or something similar) paired with a tiny vibrating motor and a battery.  For years, classroom teachers and homeschool parents have been using them to introduce even young students to the principles of engineering and robotics.

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The Science of Sound Waves


Michelle Bertkeby:  Michelle Bertke

Sound can be a difficult concept to portray because the sound waves cannot be seen or touched.  Luckily, there are several at home experiments that demonstrate the properties of sound waves.

Water tank to show ‘Sound Waves’

Sound WavesYou can use a fish tank half filled with water to give a visual demonstration of ‘sound waves’.  Water is a perfect medium to show the propagation of waves. This demonstrates how sound waves travel though the air.  There are two ways to display this activity.  One way is to simply press your hands onto the top of the water and allow the waves to be made by the pressure of your hand.  This allows students to see how waves travel though a medium.  You can also use this to point out the aspects of a wave such as frequency and amplitude.  Another way to show waves is to place a speaker next to the tank and allow the sound to produce the waves.  This can show that sound is a form of pressure just like your hand. Read the rest of this entry »


Talking Tapes | When You Want Your Students To Make Noise!


by: Tami O’ConTami O'Connornor

On a field trip with my 5th grade students to a local science museum, we saw one of the science instructors conduct a lesson on sound. It was such a simple idea, with easy-to-find materials, that I brought it home to do with my Girl Scout troop the following week.  Since then, I have modified and expanded the lesson so it would fit any elementary or middle school grade lesson plan on sound.

The first thing students must understand is the simple concept that vibrations create sound.  Even very young children can grasp this concept.  You can conduct a number of activities using tuning forks and such, but the easiest demonstration is to have students touch the front of their throats and hum.  Once they understand that the vibration of the molecules in an object creates sound, they find it easier to understand that sound cannot travel through a vacuum (an area devoid of matter).

The lesson I conducted started off with a single piece of yarn.  Each child was given a 12-inch length and asked to make sound with it.  Generally speaking, very few of my students were successful.  Some realized that, by holding one end of the yarn in one hand, and then running the yarn between the nail of their thumb and pointer finger of the other hand they produced a faint sound.  This was a good beginning!

Talking TapesNext, I gave the students a coffee cup, a paper clip, and a pencil.  I asked them to punch a small hole in the bottom of the cup with the point of the pencil and to thread the yarn through the hole.  They knotted the end of the yarn inside the cup to one end of the paper clip and then pulled the paper clip to the bottom of the cup. The paper clip was flush with the bottom of the cup, and the yarn extended from the bottom of the cup, like an animal’s tail.

Talking TapesWhile doing this, many students realized that, when they inadvertently ran their hand along the yarn, a sound emanated from the cup.  Without any additional instruction, the children began to experiment on their own.  After a short time, I gave every other student a small cup of water. I instructed them to wet their yarn in the water, without wetting the cup.  As these students ran their hand (or, better yet, their thumb nail) down the yarn it was clear that the sound became significantly louder.

What’s the science behind this activity? The friction between the yarn and students’ fingers caused the yarn to vibrate.  Because there was no way initially to amplify the sound, it remained faint.  As soon as students attached the yarn to the cup, however, the sound became much louder.  This is because the sound waves resonated within the cup and were amplified.  This is the principle at work when children play “telephone,” by stringing two cups across a distance.  The cups amplify the vibrations carried by the string to the listener’s ear.

Talking TapesSimilarly, children can change the pitch of the sound by changing the size of their mouth.  This leads to the next step of the lesson.  I distributed aluminum cans of various sizes and had the students attach the yarn to the bottoms of the cans in the same way we did with the cup.  The results should be obvious.  The smaller cans produced a higher pitch while the larger cans produced a deeper and richer sound.

Talking Tapes

Talking TapesThe final activity in my lesson involved Talking Tapes.  These tapes are utilized in much the same way as the yarn in my original lesson. By running their thumb along the plastic strip, students can actually make a paper or plastic cup talk! These tapes are specially molded so that, when vibrated in just the right way, they produce audible speech. And, nothing creates a “buzz” in a classroom like tapes that “talk” to the students!

The principle is the same as a diamond needle traveling through a record groove (if you remember records!).  The Talking Tapes include five assorted phrases and say such things as, “Science is Fun”, “Happy New Year”, and “Be My Valentine”.  Educational Innovations carries Talking Cups and a plethora of other Super! Wow! Neat! materials to teach sound in your classroom!


Chladni Plates


Martin Sagendorfby:  Martin Sagendorf

An Odd Name: They’re named for the German physicist Ernest Chladni who popularized them in the mid-1700s.  His name is pronounced: kläd’nêz.

Chladni Plates are: Thin plates (sprinkled with fine particles) vibrated perpendicular to their plane.

How? – Then and Now: Long ago Chladni used a cello bow to excite the edge of a thin metal or wooden plate.  Today, we can use an oscillator, amplifier, and an electro-mechanical oscillator.  We have a great advantage, we can easily vary the frequency of excitation thereby providing a whole vista of experimentation.

A 17 in. x 14 in. Chladni Plate in guitar shape at 200 Hz

Chladni Plate Read the rest of this entry »


Pocket Sound Blaster


Norman Barstowby: Norman Barstow

Frequency, Wavelength and Pitch:

Sound is a tone you hear as the result of regular, evenly spaced waves of air molecules. The most noticeable difference is that some tones sound higher or lower than others. These differences are caused by variations in spacing between the waves; the closer the waves are, the higher the tone sounds. The spacing of the waves – the distance from the high point of one wave to high point of the next one – is the wavelength.

All sound waves travel at about the same speed in a given medium. So, waves with a longer wavelength don’t arrive (at your ear, for example) as often (frequently) as the shorter waves. This aspect of a sound – how often a wave peak goes by – is called frequency by scientists and engineers.

The word that musicians use for frequency is pitch. The shorter the wavelength is, the higher the frequency, and subsequently the higher the pitch of the sound. In other words, short waves sound high; long waves sound low.

The Pocket Sound Blaster

Many instruments produce sound by vibrating a column of air inside a tube, e.g. flute, trumpet, and saxophone.   A sound wave is created by a vibrating object. The actual frequency at which an object will vibrate is determined by a variety of factors including the object’s size, the material the object is made from, and the medium in which the sound wave is vibrating.

Since frequency = speed/wavelength, an alteration in either speed or wavelength will result in an alteration of the natural frequency.

When you blow into the side hole of the Pocket Sound Blaster, (SNG-600) the Pocket Sound Blasterrubber diaphragm vibrates as air pressure repeatedly increases and then is released.  The vibration then resonates through the chamber and exits through the Pocket Sound Blasteropen end of the tube.

Activity #1:

As you blow into the hole of the Sound Blaster, lightly touch the diaphragm to see whether the sound changes.  Does the pitch get higher or lower? Drummers can change the tension on their drum-heads to change the pitch.

Activity # 2:  Slide Trombone

As you blow into the hole of the Sound Blaster, insert your other hand’s thumb and move it in and out. Notice any change in pitch?  For longer tubes, use a cork on the end of a barbecue skewer or thin wooden dowel to change the column of air and to make your own ‘trombone’.

Activity #3: Length of the tube (column of air)Pocket Sound Blaster

Use cardboard tubes (toilet paper, paper towels, mailing tubes) of varying lengths to make the Pocket Sound Blaster tube longer. You’ll have to taper the ends of the cardboard tubes to make them fit the outside diameter of the Pocket Sound Blaster.

Pocket Sound BlasterShorter is Higher — Longer is Lower:   Change the length of this vibrating column of air by varying the length of a tube.  Because the Pocket Sound Blaster is short, it produces a higher pitch or frequency.  This happens because sound waves can travel, or vibrate, a shorter distance faster than a longer distance.

Activity # 4:

Since the Pocket Sound Blaster tube is approximately 3″ long, make a series of card board tubes in 3 inch increments (3”, 6”, 9”, 12” etc.) to see how this affects the tone.

Activity #5:

The diaphragm of the Pocket Sound Blaster is held on by the plastic ring. Gently Pocket Sound Blasterremove the ring and explore with other diaphragm material:  wax paper, parchment paper, zip bag plastic, other balloons, latex or Nitrile glove material, etc. What changes do you discover?

Activity #6: Sound Energy

Can the sound from the Pocket Sound Blaster perform work?

  1. Try to blow out a birthday candle with the Pocket Sound Blaster.
  2. Put some confetti or puffed rice cereal in the tube and blow through the side hole. What happens?
  3. Hold the Sound Blaster so the rubber end is upright.  Place some puffed rice on the latex and blow.  Observe the movement of the puffed rice due to the vibration of the surface.