Create instruments that will make people want to get up and dance!

As you already know, music is more than just a stream of pretty sounds, such as the tinkling of chimes in the wind. And one of the things that makes it different is that music follows repeating patterns. The melody is the pattern of changes in pitch—how the notes go up and down. The string and wind instruments you made in Chapter 1 are great for playing melodies. But that is only part of what makes up a piece of music.

Music also has to have a repeating pattern that marks time. In most pieces of music, you can count the time in repeating groups of two, three, or four beats. The beat stays the same, no matter how long or short the notes are. The rhythm of a piece of music is the pattern of how the notes move along in time. Sometimes the rhythm moves along in step with the beat, but it can also make things interesting by making some beats sound stronger than others. Percussion instruments—drums and other types of instruments you play by banging on them—help keep the beat, but they are also important in creating the rhythm. The rhythm of a piece of music can be just as unique as the melody. If you can “name that tune” by hearing a few notes on the guitar or piano, you may also be able to recognize a song just by hearing the rhythm played on the drums.

Of course, percussion instruments do a lot more than thump. In fact, idiophones (instruments that vibrate throughout their whole body, like bells) and membranophones (instruments with a vibrating skin, like drums) may be the most versatile kind of instruments when it comes to changing the timbre of the sound they produce. One reason is that they can be made from almost any kind of material—wood, metal, leather, plastic, rubber, or cardboard. They can also be played in a variety of ways. You can tap them, rub them, or scrape them on their tops, bottoms, or sides, using your hands, sticks, or mallets. You can control how air affects their sound by making them closed or open, solid or hollow.

Some percussion instruments can even play a tune as sweet as any string or wind instrument. The pitch of an idiophone depends on its size and its mass, just like other kinds of instruments. On a membranophone, you can also change the pitch by changing the tension on its vibrating skin. There are even membranophones that let you change the pitch while you are playing.

Try making some of the idiophone and membranophone projects in this chapter and see how much sound you can really get out of them. Experiment with different materials and designs to find out how they affect the timbre and pitch. You may be surprised!

Got Rhythm?

There are a number of ways you can use rhythm to make a piece of music more interesting and even affect how it makes you feel.

You can make a song sound very different by singing it faster or slower than usual, or by changing the speed as you go along. The speed of a piece of music is called its tempo. Try singing a funny song at a slow crawl. (For example, the song that starts “If you’re happy and you know it clap your hands.”) Does it take on a heavy, serious tone? If you sing a sad song at a zippy tempo, does it make it more hopeful?

You can set the mood of a piece of music by choosing how many beats occur in each measure. (As discussed in the Introduction, a measure is a group of repeating beats.) The number of beats in a measure is known as its meter. In Western music, four beats in a measure is the most common. (An example is “Twinkle Twinkle Little Star.”) When you have three beats in a measure, or 3/4 time, your music can seem to swoop and soar. This is the rhythm used for the dance called the waltz. (“Rock a Bye Baby” with its gently rolling rhythm is also in 3/4 time.) Two beats per measure, or 2/4 time, can sound like two feet stomping. That’s the meter used for marches, which were originally written to help soldiers march together in formation. (Think of the song that starts “The ants go marching one by one. Hoorah! Hoorah!”)

When you put stress on a note, you make it more important than the other notes around it. A waltz usually puts the stress on the first beat—ONE two three, ONE two three. In 4/4 time, the most stress is usually put on the first beat, but the third beat also gets a little stress. In a syncopated rhythm, the beats that are normally weak get the most stress. This kind of rhythm throws you off-balance and makes you want to move. It is often used in rock and jazz music.

Standing Waves, Overtones, and Harmonics in Idiophones and Membranophones

Idiophones include bells, cymbals, clappers like castanets, shakers like maracas, scrapers, and blocks. (The spoons and the washboard from the Jug Band described in Chapter 1 are idiophones.) Membranophones are mainly drums, although the kazoo (and the comb and tissue paper from the Jug Band) can also be considered membranophones. Just like strings and winds, these instruments follow the rule that bigger, heavier instruments (or bigger vibrating parts) produce lower notes. But the standing wave patterns they produce are usually much more complicated.

Instead of going back and forth like on a chordophone or aerophone, the sound waves created inside a hollow percussion instrument like a drum bounce off the round walls at all kinds of angles. As a result, many percussion instruments make noise rather than notes. The sound of a cymbal crashing or a bass drum pounding can be used in your musical piece, but they can’t carry a tune.

Other kinds of idiophones and membranophones create layers of notes in the form of overtones. Think of the multiple notes you can hear when you bang on a gong (or a metal garbage can lid). The overtones sound fuzzy because they are not harmonics of the fundamental frequency. It’s as if you hit a bunch of random keys on a piano keyboard at the same time. Instead of a chord of pleasant notes that points your brain toward the fundamental frequency, you get a jumble of unrelated notes that never quite blend.

But some kinds of percussion instruments produce distinct notes that are clear enough to create melodies. That’s because their overtones are harmonic frequencies. In fact, to make them sound better, some instruments are specially designed to produce overtones that are closer to the harmonic.

Take the marimba, an instrument consisting of a row of wooden bars that looks very much like a xylophone. When you strike a marimba bar with a mallet, it creates a standing wave pattern that is related to the length of the bar. But the nodes (the parts of the standing wave that stay still) of the fundamental frequency are not on the ends, like they are on a guitar string. A guitar string is held in place at the ends. On a marimba, the bars rest on a support, and the ends are free to flap up and down as it vibrates. So the nodes for the fundamental frequency are further in toward the middle.

To make the note more pure, the bar on a marimba is thinned out underneath where the nodes for the fundamental frequency are found. The wood is more flexible at the thinner spots, so the bar tends to bend there. This bending action makes the fundamental frequency stronger and dampens other overtones, so the pitch sounds clear and true.

Project:
Singing Bowl

Did you know you can make metal bowls sing simply by rubbing them the right way? The singing bowl was originally used for religious ceremonies in Tibet, in the Himalaya mountains of Asia. Today it is also used in music for relaxation and meditation.

The typical singing bowl is made of bronze, a mixture of metals that can include copper, silver, nickel, and gold. It is usually small but very thick and heavy. To play the singing bowl, you rub a short, wide wooden mallet called a puja around and around the outside of the bowl. The puja is usually padded with a covering of leather or felt.

The singing bowl works thanks to stick-slip motion. As you rub the puja against the edge of the bowl, the molecules of the mallet stick to the molecules of the bowl for a moment—held together by the force of friction. Keep pushing and the mallet shoots forward just a hair, until it sticks again.

The sound of an authentic singing bowl is very pure. That’s because there is only one standing wave, and it travels around the edge of the bowl, right behind the puja. As you play, you will notice that the tone goes up and down in volume. When it’s softer, the node of the standing wave is passing by your ear.

For the best results, look for the heaviest metal bowl you can find. The stick you use as a puja should be as wide as you can comfortably hold, and very smooth.

1. Rest the metal bowl in the palm of your hand. Don’t grip it; it has to be able to resonate. If the bowl is too big, you can set it on a table, but you may need to place a soft cloth or mat underneath it to keep it from sliding around.

   

2. Hold the wooden spoon with the flat part facing up. Grasp the end of the handle as if it were a very big pencil.
3. Tap the edge of the metal bowl with the side of the wooden spoon handle. Hit it just hard enough to make it ring.
4. To keep the vibrations going and help them build, start to rub the rim of the bowl with the side of the wooden spoon handle. Go all the way around in smooth circles, pressing the spoon against the bowl firmly. You don’t have to go very fast. As the vibrations build, you will feel them in your hand. You should also hear a loud hum start to build. See if you can make the sound louder or softer by changing the speed of your mallet.

Variations:

• Try using different-sized wooden mallets to see if the sound changes.
• Try rubbing the mallet on the lip of the bowl instead of the side to see if that changes the pitch. With a metal mixing bowl, you may be able to produce two or more different notes by changing the angle of the mallet.

Project:
Tunable Water Glasses

Musical glasses are usually thought of as a party trick, but in fact, famous classical composers like Mozart and Beethoven wrote pieces for glass instruments. There are two ways to play tunable water glasses, and this activity lets you try them both. The first way is to play them like a series of bells that you strike to get a tone. Different sizes and shapes of glasses will create different notes and different kinds of overtones. The other method uses just your finger and a little water to get the glass vibrating, just like the singing bowl in the previous project. Listen for the differences between the notes and the overtones that each style creates!

1. Line up the wine glasses in front of you in size order. Take the spoon or pencil and tap each glass to hear what note it makes. Larger glasses will usually produce lower notes—but not always! The thickness and shape of the glass may affect the notes as well. Rearrange any glasses so that the notes go up in order.

   

   

2. If you want to change any of the notes, add some water to those glasses. (To keep spills contained, you may want to place each glass on a paper or plastic plate.) Adding water lowers the pitch. Why? Because adding water is like increasing the mass of the glass—the glass and the water together figure into the speed of the sound wave’s wavelength. You can tune the glass by adding or pouring out water until you get the note you’re looking for. Depending on the glass, you may be able to produce several notes. (Bigger glasses seem to have a wider range.) As you fill the glass, you may notice that some notes sound better than others. This could be because the note is one of the harmonics for the fundamental frequency of the glass.

   

3. When you have a nice selection of notes, try playing a tune with your glass organ.
4. Next, try playing the glasses by rubbing them. With one hand, hold the base of the glass. With the other hand, dip a finger in water. (If the glass has water in it, you can dip it right in the glass.) Rub your wet finger around the rim of the glass. As your finger moves around the rim, you will hear the glass start to emit a ringing tone. If you have trouble getting started or keeping the tone going, re-wet your finger or adjust the pressure of your finger on the rim of the glass. You may have to press hard at first, but you should quickly figure out how much pressure you really need. It may not be a lot. (In larger glasses, you may be able to see ripples on the surface of the water as you play. This is a result of the sound waves traveling through the water.)
5. Try playing a tune again, this time using the rubbing method. Do you hear more overtones, or different notes, than when you tap the glass?

Project:
Rainstick

A rainstick is a South American instrument made from a dried cactus branch. The needles on the cactus are broken off and the points are pushed into the hollow branch. When the branch dries out, small pebbles are poured inside and the end is plugged.

As you tilt the rainstick, you hear a soft whooshing sound as the pebbles slide around and bounce off the needles. You can make a cardboard version and decorate it however you like. Make a few with different kinds of fillings, or combine smaller materials with larger materials to get different sound effects.

1. Find the spiral seam that runs down the cardboard tube, or draw your own. Start at one end of the tube and use the pushpin to poke a line of holes along the seam. To make measuring easier, you can make the spacing between the holes the same width as one or two fingers. When you’re done, insert a nail into every hole. (If the cardboard tube is very thick, mark the spots with a pencil, then use a hammer to pound the nails in.)

   

2. Keep the nails from falling out by sticking a strip of tape over the line of nails. If you like, cover the outside of the tube with decorative paper, ribbon, or tape.

   

3. To make covers for the ends, fold a piece of wax paper in half. Place it over one end of the tube and press it down as tightly as possible. Remove the folded sheet and smooth out the wrinkles. Around the circle left by the tube, draw a bigger circle. Cut around the circle you drew to make two round end covers.

   

   

4. Attach one of the end covers by folding it back down over the tube. Pull the paper as tightly as you can and wrap some tape tightly around it. Trim off the excess wax paper, and then use long strips of tape to connect the cover to the tube, going up the side, over the end, and down the other side. You want to muffle the sound at the ends a bit in addition to securing the cover.
5. Now it’s time to add the noise. Pour in a handful of dried rice or other noise-making material. Test it by covering the open end with your hand as you tilt the rain stick. If you need to, adjust the amount of rice until you get the sound you want. Then seal off the other end with the other round piece of wax paper. Tape it securely as you did for the first end.

Variation:

• Try out different types of dried grains as noisemakers. A combination of different sizes also sounds nice.

Project:
Cup Song

The Cup Song project is all about rhythm. It’s a variation of playground clapping games, but instead of using your hands, knees, and other parts of your body, you use a plastic cup and a table. As an instrument, the plastic cup is like the stamping stick, a primitive instrument used in many ancient cultures. The stamping stick is played just as you would expect, by taking a large stick and banging the end on the ground to create a thumping sound. But because the cup is hollow and lightweight, you can create a range of different sounds by banging it on a table, against your body, and even just sliding it or running your hand along it.

The cup song became a viral hit when actress Anna Kendrick used the cup song rhythm to keep the beat as she sang the song “You’re Gonna Miss Me” in the 2012 movie Pitch Perfect. She learned it by watching a YouTube video inspired by the group Lulu and the Lampshades (now called LandShapes). (Watch the video here: https://youtu.be/DWCOYJg9ps4.) The tune was originally recorded in 1937 by A. P. Carter under the title “When I’m Gone,” and it may have been based on an even older traditional folksong.

Try to master the popular cup song rhythm in the following activity, and then see what new rhythms and songs you can create with musical cups!

1. The cup song rhythm consists of a series of moves, some of which are repeated in different ways. They include clapping your hands together, tapping them on the bottom of an upside down cup, banging the rim of an upside down cup on the table, bonking the rim of the cup against your open palm, and banging a “corner” of the bottom of the cup on the table. You can even use sounds produced by your hands sliding on the cup as you pass it from hand to hand. Here are the moves of the first part (to get the rhythm, see the sidebar that follows this activity):

   

   

   

   

2. For the second part, you have to lift the cup with the same hand as before, but make sure your thumb is pointed down. These are the next moves:

   

   

   

   

   

   

   

3. The cup should now be back in the starting position. Repeat the rest of the steps in order as many times as needed for the song. (Again, see the sidebar for help with the cup song rhythm.)
4. Adaptation: If the moves are too hard, try lifting and banging the cup on the same spot (don’t move it to the side). When you pass the cup to your other hand, don’t cross them—just slap the table in front of your free hand.

Extension and variations:

• Try to sing “You’re Going to Miss Me” or other folksongs with the cup song rhythm. Here are some suggestions:
  • “Red River Valley”
  • “You Are My Sunshine”
  • “Shoo Fly, Don’t Bother Me”
  • “Down By the Riverside”
  • “This Little Light of Mine”
  • “This Land Is Your Land”
• Ready for a cup song challenge? Get a few friends and sit in a circle or around a small table where everyone can reach the person next to them easily. When you pass the cup from one hand to the next, grab the cup from the person next to you and give yours to the person on your other side—all while singing your favorite cup song.

Project:
Cookie Tin Steel Drum

Steel drums, also known as steel pans, come from the Caribbean island of Trinidad. They were invented in the 1800s, when the British government, which then ruled the island, banned real drums because they were used by criminal gangs. Instead, steel barrels used for storing oil were turned into makeshift instruments and used in local parades. In the early 1900s, players discovered they could create different notes by making dents in the top of the barrels, and it was then that the steel drum was born.

The simplest steel drum you can make is a dudup. It has only two notes and is used as a rhythm instrument. Try making a dudup before you move up to a drum with more notes. This project was adapted from directions on www.toucans.net.

1. To make the steel drum, remove the lid from the cookie tin (save it for later so you can store your mallet inside the tin) and turn the cookie tin upside down. With the marker, draw a line across the bottom of the cookie tin that divides it into two parts, one a little larger than the other.

   

2. With the hammer, carefully tap along the line to stretch the metal downward. You should end up with a shallow valley running along the line.

   

3. Time to test the drum. Balance the tin on the palm of your hand (if it’s too large, lay it across your lap, or set it up on two piles of books with a space in the middle). Hold the mallet (a pencil or other DIY drum stick) loosely in your other hand. Then tap on one side of the line and then the other to see what pitches you get.

   

4. To adjust the quality of the sound as well as the pitch, you can hammer the line down a little more. You can also hammer each side separately from inside the tin. This will create a little “hill” that will stretch the metal even more. As you know from working with string instruments, more tension means faster sound waves. Your dudup is ready when it produces two clearly different notes on each side. Ideally, one side should be about four or five notes lower than the other; however, the exact pitch doesn’t matter, because the dudup’s job is just to create a beat with its two notes.

Extensions:

• Divide your drum surface into three or more sections to create extra notes.
• Build a stand for your drum. The string loops just described can also be used to hang the drum on a stand with arms on either side. Make a box-shaped frame for your drum from PVC pipe or wood. Add hooks to let your drum hang.
• Try some different mallets. Real steel drum mallets have relatively short handles that let you tap the drum at a close angle. They also have a smooth or round rubber tip. Try a small foam paint brush, or take a short dowel and attach a rubber ball or make a rubber-band ball on the end.

Project:
Wrenchophone

The Wrenchophone is a metallophone, a xylophone-like instrument with metal bars. (A true xylophone has bars made of wood.) Surprisingly, the metal tools that make up the Wrenchophone produce beautiful ringing tones. That’s because you are hearing mainly the fundamental frequency, without other overtones that make the timbre fuzzier. The base you put together to hold the bars helps to dampen the other overtones that might get in the way of the fundamental frequency. Try to make this Wrenchophone and see what kind of tones you can produce using found objects!

1. Take the wrenches or other metal objects you are using for your bars and lay them in a row, longest to shortest. Space them so they are easy to play. This will give you an idea of the size and shape of your Wrenchophone.

   

2. Can you figure out the best place to support the bars? That’s right, underneath the nodes, the parts of the standing wave that do not move! To find the nodes, measure each bar, and put marks at the spots that divide each bar into quarters. (You can do this quickly by eye by dividing the bar in half and then dividing each half in half.) The nodes for the fundamental frequency—the main note you hear when you set the bar vibrating—are near the outside marks, at the either end of the bar. (To be exact, the marks are 22 percent of the length in from each end of the bar. That is a little less than 25 percent, or one quarter, of the length.) For example, if your wrench is 12 inches (30 cm) long, the supports should go at about 3 inches (7.5 cm) and 9 inches (22.5 cm). If it’s 4 inches (10 cm) long, they should go at around 1 inch (2.5 cm) and 3 inches (7.5 cm).

   

   

3. The bars of your Wrenchophone need to rest on a base that will support them but also let them vibrate. Unlike string instruments, the ends of the bars are loose and also vibrate up and down. So your base has to let both the middle and the ends move up and down. You can make a quick and temporary base by laying two chopsticks horizontally (side to side), and resting two more chopsticks vertically (up and down) on top of them. To cushion the sticks on top, slide some rubber pencil grippers over them, or wrap them in foam padding. The cushioning helps dampen the overtones from interfering with the fundamental tone of the metal bars. Place the bars on the cushioned chopsticks so that the marks sit above the supports. As the wrenches get smaller, the chopsticks will need to get closer, until they are almost in a V shape.
4. Make a pair of mallets by sliding a large wooden bead onto the narrow end of each remaining chopstick until it is tight. Use a little white glue to hold it in place if you need to.

   

5. Test your Wrenchophone to see how it sounds. If you can, try to find bars that will create at least one full octave. This will allow you to play many songs. However, if you can’t manage to get every note, pick a nice arrangement of notes that sounds good to you. You may need to add or subtract bars, or rearrange them in a different order. If you are mixing wrenches made by different companies, you may find that the variation in weight between them means that a shorter wrench plays a lower note than a longer one.
6. Once you have the chopsticks where you want them, you can connect them permanently if you like with rubber bands, zip ties, or glue at the places where two chopsticks cross.

Variations:

• Try using different mallets to see what kind of sounds you get, such as the pencil or rubber-band-ball mallets from the Cookie Tin Steel Drum project. You can even just use a leftover wrench as a mallet.
• Try making a xylophone-type instrument out of other materials. Remember, if you are making your own bars and they are all made of the same kind of material, you can figure out the harmonics by measuring out simple fractions (½, ⅔, ¾) of the longest bar. Here are some suggestions for materials to try:
  • PVC pipe
  • Copper pipe
  • Tree branches or driftwood
  • Bamboo poles
  • Stones (use a rock as a mallet)
  • Pieces of ceramic tile
• Try other ideas for supporting the bars. Here are a couple of suggestions:
  • Suspend the bars from strings; if you drill holes through the bars, place the holes at the nodes.
  • Place a line of cup hooks along two strips of wood and hang rubber-band “hammocks” between them to support the bars.

Project:
Packing Tape Bass Drum

Making a membranophone requires a material that can be stretched tight but stay stiff enough to make a booming sound when you tap on it. The earliest drumheads were made of animal skins. Today many drumheads are made of sheets of plastic. The drumhead on this simple bass drum is made of clear plastic tape that is stretched across the openings. Hitting one of the skins causes the air inside to vibrate and makes the skin on the other side vibrate too. This helps amplify the sound, making the bass drum one of the loudest kinds of (nonelectric) instruments. This project was adapted from a YouTube video by Alec Duncan of Child’s Play Music.

1. If the can or container you are using has a metal bottom, use the can opener to remove it. Your drum needs to be open at the bottom.
2. Choose one end to be the top. You are going to start to make the drumhead by stretching a piece of packing tape straight across the opening so that the tape goes through the center of the circle. Attach one end of the tape a few inches (5–10 cm) below the edge. Stretch the tape as tightly as you can as you bring it across to the other side of the can. Then press the same amount of tape down over the side before cutting it.

   

3. Repeat with a second strip of tape, but turn the can so the new strip forms an X with the first piece. Add a third strip between the first two strips. Then add a fourth strip in the remaining gap between strips to make another X.

   

4. Continue layering strips of tape across the opening the same way until the entire top of the can is covered. Be careful not to leave any openings. Then go around and make a second layer all the way around. When you have two complete layers of tape across the top of the can, turn it upside down. Press on the tape from the inside (sticky) side to make sure all the layers are stuck together tightly.

   

5. Use a mallet (see the “Cookie Tin Steel Drum” or “Wrenchophone” projects) or your hand to play a rhythm on your drum. See what kind of sounds and beats you can get out of it!

Extension:

• Try making several drums using different containers in different sizes.

Project:
Balloon Drum

For this project, you will create a kettledrum-type instrument. Instead of a tube (either open or with drumheads covering openings on both sides), kettledrums (also called tympani) consist of one drumhead that seals the opening of a bowl-shaped body. Sound waves bounce around inside, smoothing out the tone. In fact, real kettledrums are tunable. Players use winding keys like the pegs on a string instrument to make the drumhead tighter or looser, which raises and lowers the pitch. Kettledrums even have pedals that allow them to play multiple notes. See what kind of notes you can get with a stretchy latex balloon drumhead that can be pulled tighter over the opening to change the pitch.

1. To make the balloon easier to stretch, blow it up first and let the air out. Then cut the neck off the balloon.

   

   

2. Start to stretch the balloon over the opening of your can. It may help to hold the can between your knees and to have another person on hand to grab the balloon from the other end. “Hook” the edge of the balloon over the rim of the can closest to you. Then pull the two opposite “corners” until you can stretch them over the rim of the opening on the far side. If you have trouble getting the balloon on, or making it stay on, you may need a bigger balloon (or a smaller can or bowl).
3. Test the sound with your hand, a stick, or a mallet. To tune your drum, you can carefully pull the edge of the balloon up or down to make it fit tighter or looser around the can.

   

4. Once you’ve got it adjusted to your liking, wrap a rubber band or strip of electrical tape around the edge of the balloon to hold it on. If your drum body is a round bowl, the balloon may stay on by itself.

Variations:

• Use plastic food wrap instead of a balloon for your drumhead. Or, for a really tight fit, use plastic shrink wrap that’s made for insulating windows. You’ll have to tape it on first, then use a hair dryer to shrink it until it makes a good sound.
• Try making a set of drums using different containers in different sizes.