Tuning Fork Lab

GUIDING QUESTION:

How does density of various solids affect the way the sound waves travel from the turning fork?

HYPOTHESIS:  

I think that sound from the tuning fork will travel best in metal, because I think that metal is the most dense of all the materials we are testing the tuning fork with.  This means that the sound will be louder and clearer, because there won’t be so much space between molecules/particles in the metal for the sound to travel through.

Control=Force, Tuning fork, Frequency, Length, Temperature (Loudness change)

Manipulated=Materials, Temperature

Responding=Pitch, Loudness, How long the sound lasts (Properties of sound)

EXPLORATION:

Materials:

Tuning Fork

Metal

Plastic

Wood

Paper

Notebook

Pencil (To record)

Procedure:

1. Find and gather the densities of following materials below.

2. Use a tuning fork, hit it against a manipulated variable.

3. After banging towards the object, place the small part or the edge of the tuning fork towards your ear.

4. Record the vibrations and the loudness of the manipulated variable.

5. Use this method to find the loudness of the other materials.

Data Tables:

Tuning Fork: 512C

Weight: 27.3g

	Metal	Wood	Plastic	Paper
Density	7.85g/cm3	5kg/cm3	7.85g/ml3	0.78g/cm3
Loudness	Can be expressed as very loud	(Ultra) VERY Loud, and its vibration lasts very long.	Bit loud, Bit soft - it is hard to determine	Very Soft; can’t hear that much
Other Observations	Measured on the metal attached to the board. The sound of the metal has caused disturbances to the classmates next to me (vibrations last for a long time.)	Measured on a wooden chair Could have similar frequency with metal	The plastic containing no materials didn’t vibrate that long due to the manufacture quality  (plus, the loudness might vary on the quality of the plastic)	The paper lasted only about 1 sec, the vibration lasted very short. Maybe the heavier the manipulated variable, vibration last longer
Vibration (Time Lasting) 3 Trials	10 Sec 8 Sec 8 Sec	11 Sec 10 Sec 8 Sec	4 Sec 4 Sec 3 Sec	2 Sec 1 Sec 1 Sec

Analysis of Data:

The table above shows that metal and wood are very similar in transmitting sound from place to place.  They are both pretty efficient, as they were pretty loud and the sound lasted for a very long time.  Wood might be a little better for listening to tuning forks, though, because the sound lasts a few seconds longer than on metal.  

 

Conclusion: 

My hypothesis was incorrect.  I believed that metal would be the best substance for listening to sound from the tuning fork, but I was wrong.  It was really wood that was the best sound transmitter.  This makes sense, because after we discovered the densities of each material, we found out that wood is more dense than metal.  There might have been some error in how we recorded the density of each material.  We looked them up on the internet, and we discovered that each type of metal, wood, plastic, and even paper, has a different density (steel and aluminum are different, oak wood and maple wood are different, etc.)  We weren’t sure which metal, plastic, or wood we were using, so we just picked the option that made the most sense.  Unfortunately, we had/have no way of telling whether or not what we thought made sense is actually true, so there is a big possibility there is error there.  

Further Inquiry:   

If I were to do this project again, I would also include hollow objects.  When testing the tuning fork and the sound it produced on metal, wood, paper, and plastic, we rarely used something that was hollow.  The chair is not hollow, paper is not hollow, plastic is not hollow, and metal isn’t either.  I have my own tuning fork at home that I use to tune my violin, and I always place it on the body of my instrument to hear the sound.  Usually, it is clear, loud, and easy to hear:  I can hear it well without placing my ear on the instrument.  This might be because since a violin is hollow, there is more room for the sound to reverberate and echo.  This may double or triple how loud the tuning fork is.  Next time, we should do wood, hollow wood, metal, hollow metal, plastic, hollow plastic, and paper.