Scientific Experiments with Sound

Striking – water glasses

Material Description:

• Two sets of 4 identical straight sided glasses. One set is marked in a graded fashion to indicate the amount of water needed to produce the first 4 tones of a major scale the other set has no indication.
• Pitcher of water
• Mallet
• Bucket

Method:

1. Pour water into the 4 marked glasses.
2. Strike each lightly with the mallet and grade them in order from lowest to highest.
3. Pour water into the other 4 glasses so that their sounds will match the sounds of the first 4 glasses.
4. What do you observe?

Statement:

As you strike the glass, the glass vibrates, producing a musical tone. The more water there is in the glass, the slower the vibrations. Slower vibrations produce lower musical tones.

Striking a tuning fork

Material Description:

• Tuning fork
• Wooden table/box
• Dish of water
• Towel / sponge

Method:

1. Strike the tines of the tuning fork gently on your knee and then place the base of the tuning fork on a wooden surface. Notice the sound produced.
2. Strike the tines of the tuning fork gently on your knee and then place the base of the tuning fork in a dish of water. Notice the sound produced.
3. What do you observe?

Statement:

When the tuning fork is held in the air, a very soft sound may be heard. When the tuning fork is placed on wood, a louder sound is produced. Wood is an excellent conductor of sound waves. It acts as a “sounding board”. Water is a poor conductor of sound. The vibrating tines of the tuning fork make small waves in the water.

Note: A tuning fork that is marked A 440 means that it vibrates 440 times per second. This is the sound that is played by the oboe before an orchestra concert begins in order that all the instruments may tune themselves to the same pitch.

Striking – spoon on a string

Material Description:

• Metal spoon on with a string or thread is tied (18 inch in length).

Command:

1. Wrap the loose end of the string or thread around your index finger two or three times.
2. Gently place that finger in your ear.
3. Lean over slightly so that the spoon hangs freely in front of you.
4. Tap the spoon with your finger.
5. What do you observe?

Statement:

A bell like gong will be heard. The vibrations travel up the string with greater intensity than in the air.

Variations:

• Tap the spoon with a metal object such as a coin.
• Tie two strings or threads to the bottom corners of a wire coat hanger. Put both fingers in the ears and have another person tap the hanger with a wooden spoon.

Note: Elementary children will usually begin to explore various items in the classroom environment by suspending them on a string and striking them to see if they will produce a sound. The children could make lists of those that do and those that don´t.

Sliding – making a crystal glass ring

Material Description:

• A crystal or fine wine glass with marks at 3 graded levels.
• Pitcher of water
• Towel/sponge
• Finger bowl containing water
• Bucket
• Tray

Method:

1. Wash your hands
2. Pour water from the pitcher to the lowest mark on the glass.
3. Dip your finger in the bowl of water.
4. Steady the glass with your other hand.
5. With moderate pressure slide the tip of your wet index finger around the rim of the glass until a clear ringing tone is produced.
6. Repeat the procedure, this time with the water at the middle mark.
7. Repeat the procedure, this time with the water at the highest mark.
8. What do you observe?

Statement:

Sliding the finger tip on the rim of the glass makes the glass vibrate. This vibration produces a sound. The more water in the glass, the slower the vibrations and the lower the sound. The vibrations of the glass also produce waves in the water.

Blowing – bottles

Material:

• Two sets of identical bottles.
• One set is marked in a graded fashion to indicate the amount of water needed to produce the first tones of a major scale the other set has to indications.
• Pitcher of water
• Towel/ sponge

Method:

1. Pour water into the 3 marked bottles.
2. Blow across the top of each bottle until a musical tone is produced.
3. Grade the bottles in order from lowest to highest.
4. Pour water into the other 3 bottles so their sounds match the sounds of the first 3 bottles.
5. What do you observe?

Statement:

As you blow across the opening of a bottle, the air column inside vibrates, producing a musical tone. With more water in the bottle there is less space for the air column. The shorter the air column, the higher the sound.

Other activities:

Children may play simple tunes (e.g. Hot crossed buns) by ear on the bottles. One child may play by alternately picking up and putting down the bottles as needed or 3 children could play, each having one of the bottles and playing whenever their note is needed.
Note: Be sure to set a policy for cleaning the bottles so children are not sharing germs with other.

Blowing – soda straws

Material:

4 soda straws or hollow reeds of graded lengths bound together side by side so that the tops are all even and the bottoms are graded from longest to shortest.

Method:

1. Place the long straws top edge against the bottom lip. Pucker lips as for whistling and blow across the top opening of a straw until a musical tone is produce.
2. Do the same with the other straws.
3. What do you observe?

Statement:

The longer the straw, the lower the tone produces.

Plucking – playing a rubber band.

Material Description:

• Styrofoam/paper cup
• Rubber band cut so that it is one long piece.
• Half a match stick.

Method:

1. Make a small hole in the centre of the bottom of a cup.
2. Tie one end of the rubber band around the match stick.
3. Push the other end of the rubber band through the hole in the bottom of the cup.
4. Hold the cup in one hand and pull the end of the rubber band with the other hand.
5. As you vary the tension of the rubber band, have another person pluck the middle of the rubber band
6. What do you observe?

Statement:

The more tension there is on the rubber-band, the higher is the sound.

Note:

A small musical instrument may be made by placing 3 rubber bands around an open box. By adjusting the tension on the rubber band, the first 3 notes of a scale may be produced. A simple song may be played on the instrument.

Instruments:

Instruments are rally vibrating machines. As they vibrate they make the air around them vibrate, too then the vibration go travelling through the air and when they reach the eardrums of the player (which they do in the tiny fraction of a second) that ear drum vibrates also and that give the player the sensation that we call “ sound”. A fraction of a second later the vibrations reach the ear drums of the audience (if there is no) and then that audience has that same sensation. Nearly all instruments are so made that the player can make them vibrate quickly, which produces the sensation of what we call a high sound or slow, which produces what we call a low sound.