The tuning fork sound lab

The sound 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 objects which have a higher density will not transfer sound as well as the objects with lower density will. This is because the objects which are denser have particles that are more packed together, which prevent the longitudinal waves of sound from travelling as easily, as they do in mediums where the particles are less packed, and the density is lower.
Exploration: For this lab there are several materials that I used. Firstly, I used a tuning fork, which was 341.3 F. The materials that I did the lab on were the bin (plastic), the whiteboard (aluminum), table (oak wood), window (glass), cardboard textbook, as well as plastic bottles.

Step 1. Choose a tuning fork, and then choose the materials with which you would like to test the sound on.
Step 2. Tap the tuning fork on the table, or any other stable object, and hold the opposite end to the object that you are testing.
Step 3. Hold your ear to the object that you are testing, and listen to the sound.
Step 4. Describe the sound that you heard, including the pitch, the loudness, etc.

Controlled variable: The tuning fork, and the force we apply, as well as the temperature we did the lab in.
Manipulated variable: The variable we changed was the different objects we used, and the different materials we used.
Responding variable: When we combine the two variables above, the different result we would get is the pitch, loudness and even intensity of the sound waves.

Record and Analyze: Below you can find the information table, where we recorded all our observations.

I see that the sound traveling only partially gets affected by the density. Our observations are also influenced by how far from the tuning fork I am, as well as how loud I hit the tuning fork, etc. All of those variables can affect what we hear, and what we observe.

Conclusion: From the data that I have collected, I can conclude that the density only partially affects what happens to the sound, and how sound travels. It is very difficult to keep the force the same, because you never know how hard you hit the tuning fork the previous time. My hypothesis was correct, but, as I said above, it was very hard to make this lab completely fair. I can also conclude that it is not very easy to write about the pitch and the loudness for each material. Sometimes, the pitch could be very high, and the loudness quite faint. This made it quite difficult to interpret the data.

Further Inquiry: As I said above, I think there were many places for error, which we didn’t necessarily see at first. We didn’t pay much attention to the force we applied, and I think that is something we should have done. Also, it was hard to control the temperature, so we never really knew whether the classroom is colder or warmer then it used to be the previous class. From the data, I can see that density is not everything that affects the way that sound travels, and why it has higher or lower pitch, different loudness, etc. One of the questions that I have unanswered after completing this lab is what are some other factors that affect the traveling and the properties of longitudinal sound waves.

Sites used:
http://wiki.answers.com/Q/What_is_the_density_of_aluminum
http://en.wikipedia.org/wiki/Oak
http://answers.ask.com/Business/Constructions_and_Materials/what_is_the_density_of_glass

Properties of sound (amplitude, frequency, pitch, etc)

This lab was supposed to help us determine how changing amplitude and frequency can change the sound percieved. We paired up with someone else, and we were supposed to have one person tighten the thicker rubber band, and the other person pluck it. Firstly, we were supposed to plucj it from the distance of one centimeter, two centimeters, three centimeters, and then finally four and five centimeters. My hypothesis is that the higher we pull one part of the band, the louder the sound will be. However, I am really not sure about the pitch.

My conclusion is that the thicker rubber band acted as a guitar string. As you know, as you pluck the guitar string more, the louder the sound it would be. I can conclude this because the more you pluck the string, and the further you take it back, the bigger disturbance you are causing to the air particles, and therefore, the vibrations will cause a louder sound, and a higher pitch.
I found this experiment very interesting, and it deepened my understanding of the sound waves, as well as what can cause bigger and smaller disturbances, and vibrations. I would have liked to do this experiment with a thinner band, because I think that the pitch would be even higher.

How people produce sound

There are different parts that make people produce sound, and those are the vocal cords, the epiglottis, the ventricular folds and the pharynx. The vocal chords vibrate, creating different pitches, and different sounds. Their vibrations are sound waves. The disturbance, or the thing that causes the vibrations, is the air that is pushed up from your lungs. The vocal chords for people with deeper voice are usually longer then the vocal chords of people with voices which are much higher. However, the sounds produced by your larynx, are majorly affected by your teeth, mouth, and tongue. Depending on how you move your tongue, or teeth, the sound that comes out will be different. Let's take two letters as an example: "d" and "t". When you first look at them, and look at the way you pronounce them, you can see that the way of pronouncing them is quite similar, but not completely the same. When you pronounce "t", your tongue touches your teeth more. A similraty that both of these letters have is that they are both produced when the breath is completely, or partially stopped, like all consonants. I am sure that you have noticed that men usually have a deeper, and lower-pitched voice than women. This is because during puberty, testosterone deepens men's voices, and makes their vocal boxes expand. However, when they are little, both boys and girls have a voice of similar pitch. Again, this is because the younger boys haven't gone through puberty yet, and their voices didn't deepen yet.
Larynx, and the vocal chords, can get an infaction, and can stop working, just like some other organs in our body. The disease that can cause this is called laryngitis. Laryngitis is an inflammation of the larynx. It makes your voice really hoarse, and makes the vocal cords irritated. There are several factors that can cause laryngitis, and those are overuse of the vocal cords, over-consumption of cigarettes and alcohol, etc.
For this experiment, there wasn't really a special procedure that we followed. All we did was pair up with a partner, and pronounce different words, such as "sister", "boat", etc. Then, we observed what we do with our mouth,  teeth and tongue to say certain words.

For the table below, it was really difficult to record data for a few reasons. Firstly, it was quite difficult to see where the sound was open, and when was stopped (when you stopped the air coming out from your mouth and vocal cords by using your mouth, teeth or tongue). In the table below,I just found one letter that I believed wasn't completely closed, and let a bit of air pass out of your mouth.

Earthquake Safety (What to do and how to protect yourself in case of an earthquake?)

There are several things that you should do if you were in an earthquake. The first, and most important thing, is that you should stay away from wobly, heavy objects, that could collapse and hurt you. This would also include windows, and any other glass objects. You should also move away from bookshelves. The smartest and safest thing you can do is hide under a table. Drop, cover and hold on! This means that you should go under the table, and hold on to it. If it moves, hold on, and move along with it. One thing that you shouldn't do under any circumstance is to panic. When you panic, you do not think straight, and you can get eve more hurt, and cause an even more dangerous situation then it already is.



Stay away from!

         



Of course, before you hide, or take any precautionary measures, you need to remember to turn off as many electrical devices as you can. This includes lights, stoves, etc.

If you are standing outside during an eartquake, you should try and find an open space. There are several reasons for this. Firstly, you do not want to stand near tall buildings, because they could collapse and kill you, especially if the foundation isn't very good. Trees and bricks could also fall, and either seriously hurt you or kill you, or trap you. When you are trapped, you can die from hypothermia, or from lack of water and food. Another thing that you should watch out for if you are outside is the electricity wires. The electricity and energy that they carry can be lethal during an earthquake.

Safety Kit!

One thing that you need during an earthquake is a safety kit. A safety kit contains carious objects that you would need if someone got injured during an earthquake. Those injuries could vary, from stepping on glass, to heavy objects falling on you, etc. The main parts of an effective earthquake safety kit include food and water for at least 3 days. This food should not expire quickly, and should be easily portable. The kit should also include water purification tablets, or a portable water filter. You never know where you might be when an earthquake strkes, or where you will have to go, so a water purification tablet-filter is necessary, since humans need at least 3 gallons of water a day. The kit should also have band-aids, desinfactants, gauze, and other materials for treating wounds. There should also be a flashlight, with extra batteries, as well as some sort of communication device, to help the emergency personnel  find you (this could include a radio, walky, talky, or something similar).



Why is our home not completely earthquake-safe?

There are a few reasons why I do not consider my home very safe in case of an earthquake. Firstly, all of the beds are next to or close to the windows. This is not very convenient, since glass can be very dangerous when an earthquake occurs. We also have a huge lamp that towers over the whole living room. this is very dangerous, since it can fall, and hurt someone really badly. In my home, we have quite a few shelves with books, clocks and other items on them, which could also be dangerous in an earthquake. In the living room, and our dining room, we have a few big framed pictures, whose sharp edges could be even lethal for someone.
To make my home more earthquake-safe, we would move the beds fruther away from the windows, or take off the walls some of the bigger paintings.
After the earthquake is over, all of us would go out, to check whether anyone is injured. If someone is hurt, we would either call the neighbours around us for help, and see whether any of them are hurt, or we would use the basic safety-kit materials that we have to help. Then, we would listen to the radio, and see how bad the situation is, and when it is safe to go outside, or to call/search for help.