Tuning Fork Lab

Guiding Question: How does the density of a material affect the properties of sound travelling from a tuning fork?

Hypothesis: I think that the denser the material the object the louder the sound is going to be.

Materials:

- Tuning fork C256

- Hollow wooden box

- Desk

- Wall

- Metal Railing

- White board

- Notebook and Pencil to record observations

Procedure:

1. Gather all the materials above.

2. Take your tuning fork, and hold it by the side with only one piece of metal. Gently bang it on the side of a desk. Place the small piece of metal of your tuning on the desk, and with your ear on the desk, listen to the sound vibrations. Record your observations.

3. Do this for all your other materials.

Data Chart:

Medium	Density	Sound description
Hollow wooden box	0.63g/cm3	Low, buzzy sound
Desk	0.63g/cm3	Low, quiet buzzy sound
Wall	1.1g/cm3	High sound, loudest, short vibrations
Metal railing	8.60g/cm3	Very high, one long, dragged out sound
White board	2.7g/cm3	Higher than wooden box, kind of fuzzy

Data Analysis:

From my data I can see that this was my order of denseness in my mediums; hollow wooden box and desk, wall, whiteboard, and metal railing. This also sort of combines with my observations for each sound, since the least dense materials made lower sounds, and the materials with higher density made higher sounds. The metal railing, the material with the higher density had a very high sound, and according to me it was one long and dragged out sound, with no buzziness or fuzziness. Something weird that I noticed was that the hollow wooden box and the desk both have the same density, but according to my observations the desk had a quieter sound than the hollow wooden box. I later found out that the reason that the two mediums had the same density was that they both were made from oakwood. Perhaps the reason that the desk had a smaller sound was that it was bigger and the waves were more spread out. Otherwise, I might have made unaccurate measurements such as not tapping with the same force on the tuning forks, or possibly having my ear from different distances from the source of the sound.

Conclusion:

Looking at my data, I can conclude that sound travels faster in denser materials than in less dense ones. Also, the higher sounds come from the denser materials. I can see this because my densest material, the metal railing, with a density of 8.60g/cm³ , produced a much higher sound than the wooden box and the desk, which were made of oakwood and had a density of 0.63g/cm³ . This proves that sound travels faster in denser materials. This is probably because since sound is a longitudinal wave it needs a medium to travel through. (otherwise it can’t travel). I think that the more medium the sound had the faster it can travel through it. Therefore, the more compacted the medium is (the more dense it is), the sound can travel more quickly through it. This also means that liquids such as water transmit sound slower than for example rocks, so basically solids can carry sound faster than liquids. This also means that gas would be even harder for sound to travel through, since it’s even less dense. Therefore, sound is heard better travelling through solids than travelling through anything else.

Further Inquiry:

After this experiment, something I’d like to do is try a lab comparing different tuning forks to see which works better. Then we could compare them and see how the sound changes through each one in the same medium. We could also have tried some other mediums, such as glass, the floor or maybe even a laptop, if we do it carefully. Something else that I’d like to do is to try using the tuning forks and recording observations through a liquid, instead of using a solid as a medium. However, we might need special instruments then, since it probably won’t be so easy to hear it. It would also be cool to try sound through a gas, but I don’t know how that’d work either, since you can’t really tap the tuning fork against gas. Well, maybe you could, but it wouldn’t make a sound, or at least one that is hearable to humans.

Sites Used

http://www.wolframalpha.com/

Current Event about situation in Japan

http://www.nzherald.co.nz/japan-tsunami/news/article.cfm?c_id=1503051&objectid=10712802

After the earthquakes and tsunami in Japan, everyone has been evacuated out of the area. One of the places affected by the natural disasters is Fukushima Daiichi. Everyone was evacuated but 50 employees working to avoid the possible meltdowns of the earthquake- hit nuclear power plant. These workers are working and trying to cool down fuel rods by injecting seawater into them. The is a very dangerous job, not only because of the potential danger of the power plant breaking but also because of the radiation and health care of the workers. In one hour, David Richardson states that those at Fukushima are receiving in one hour the same amount of radiation as a United States nuclear worker receives in his whole career. This could lead to long- term health issues, and diseases such as cancer.

"You are still breathing this into your lungs, and there is passive absorption in the skin, eyes and mouth and we really do not know what long-term impact that would have," says Lee Tin-lap, a toxicologist at a Hong Kong university.

Recently the radioactivity showed that the radiation level was 400 millisieverts per hour, which is 400 times the amou nt the normal parson is supposed to have in a year.

"There is no doubt it is an amount that would have (a harmful) effect on the human body”, says Chief Cabinet Secretary Yukio Edano.

Now, we have proper gear and clothing against radiation, but this hardly compensates for all the harmful things in the air. Now, around 200,000 people have evacuated from nine towns within 20km of the Fukushima Daiichi nuclear power plant.

I am pretty shocked hearing that the situation in Japan is this bad- I thought it was just a tsunami with no major consequences, except for slight damage. However, this has been affecting lives of a great number of people. I think that we shouldn’t be risking the lives of these workers to make sure the power plant isn’t going to explode, since the radiation and just danger in general from more natural disasters, or the nuclear power plant itself. Maybe, instead we could pour the seawater in through planes or helicopters, not risking human lives. Otherwise, if our technology is advanced enough we could use robots. If the nuclear power plant is going to explode, 50 workers pouring seawater on it probably isn’t going to stop it from happening. Then they would die together with everyone else. If it doesn’t explode, they would just be wasting their health and harm their bodies, exposed to lethal radiation. Because of the situation with all the natural disasters, I just think that the wisest thing to do would be to evacuate the area and just get everyone as far away as possible from the power plant.

Properties of Sound Lab Summary

Experiment 1

Distance away from middle	Description of sound
1 cm	Low drum beat
2 cm	Higher than 1 cm
3 cm	Higher than 2 cm
4 cm	Higher than 3 cm
5 cm	Higher than 4 cm

Experiment 2

Tightness	Description of sound
Tightest	Higher pitch than tight
Tight	Higher pitch than short
Loose	Low, soft sound

Thickness of Rubber Band	Description of sound
Thick	Low drum
Thin	Higher drum

Length of rubber band	Description of sound
Shortest	High pitch, soft sound
Long	High pitch, louder sound
Longest	High pitch, loudest sound

Conclusion Questions:

How did the sound change when you changed the amplitude (how far the rubber band was away from the middle point)?

The pitch of the sound gets louder.

What happened when you changed the thickness, length, and tightness of the rubber band?

1- The thicker the rubber band the lower the pitch of the sound.

2- The longer the rubber band the louder it is.

3- The tighter the rubber band the higher the pitch.

Sally is playing the guitar and notices that one of her strings is flat (pitch is too low). What can she do to fix it?

Sally should tighten her string. In this way, the pitch will be higher, and she won’t have a flat sound.

How People Produce Sound

From this lab I have learned that a sound can be produced with many different parts combined of your mouth. This is mainly when your breath is party stopped by your tongue, teeth, or lips. Some sounds are made from similar movement inside your mouth, such as the letter t and d. When your mouth muscles pronounce these letters, your tongue starts at the top part of your mouth and goes down, and your lower yaw goes down. However, there are many different letters, and all of them make specific mouth movements. The vowels, (a,e,i,o,u,) and the letters k and g are made without closing your mouth at all or without having anything block the sound from your vocal cord. These are called open letters. All of the other letters are called stopped letters, since there is some sort of a barrier from when they leave the vocal cord to when they are outside your body. Another thing I learned from this lab is that we have true and false vocal cords. From this experience I am now also able to visualize a vocal cord, which will be very helpful as we continue studying sound.