## Friday, 16 May 2014

### Students in class 3 have been conducting experiments about sound.An experiment we recently conducted was about sound vibrations. In this experiment we used strings of various lengths, widths and materials and tested to see which string was most successful, when speaking to our partner of distances over two meters.

Here is Paige and Gloria's experiment

Sound - String telephone data sheet

What are the two thing that made the sound travel well in this experiment?
• The string has to be pulled tight so the string can vibrate so that the air molecules can move to your ear.
• You have to put a small hole at the bottom

Why did the sound travel well in each case?
Because the string vibrated which means that the air molecules moved and went into our ear.

What are the two thing that made the sound travel poorly in this experiment?
If you did a big hole the string wouldn't vibrate properly. If the string wasn’t pulled tightly then it couldn’t vibrate too.

Why did the sounds travel poorly in each case?
The thicker the string the better the sound. If you have a long as as as as  string and it is pulled tight you will still be able to hear each other.

How do sounds travel from one cup to another?
Here is why it works. When one person talks into his/her cup, the bottom of the cup vibrates back and forth with the sound waves. Imagine the bottom of the cup moving back and forth very quickly (1,000 times per second or more) with the sound waves of the speaker's voice.
The vibrations travel through the string by pulling the string back and forth. Therefore, the bottom of the second cup should start to vibrate back and forth just like the bottom of the first cup is vibrating, producing sound waves.
The second person can hear the sound waves and can therefore hear what the first person says.

Name: Paige and Gloria

Title of experiment: Cup Telephones

Question:
(What do we want to find out?)
We want to find out who it works and which string will let us hear each other better.
Hypothesis:  (what do you think will happen?)
We think that if the string isn’t pulled tightly then there will be no sound.
The Plastic Rope will work the best

Procedure:
How will we find out?
(Step by step)

Step 1 : Poke a pin sized hole in the bottom of the polystyrene cup
Step 2 : Get the cotton string and thread it through the bottom of the cups.
Step 3 : Tie a bit of popsicle stick to the end of each string and put the popsicle stick in the cup.
Step 4 : One person stays in place and the other goes back until the string is pulled tightly
Step 5 : Whisper into polystyrene
Step 6 : We untied the string from the popsicle stick and tied the next bit of string which was the wool.
Step 7  : We tied the the wool to the popsicle stick
Step 8 : After testing we untied the wool and tied the plastic rope on and tested that.

Results:
What actually happened?
With the 1st string (Cotton) we found that it was quiet. If the string wasn’t pulled tight enough then we could not hear each other
With the 2nd string (Wool) it was a bit louder. The tighter the better. The looser the quieter.
With the last string (plastic rope) we could hear each other the best.

What did we learn?
What we learnt was we don’t need fancy phones to communicate, however this is except if you communicate and the person is far away then you could only hear them quietly because the vibrations can’t travel far enough.

### Here are what Quziyah and Mua discovered throughout and following their experiment

Talking through cups - Scientific experiment

Question:
We want to find out if we could hear each other from far just by using cups, a small string, a small rope and a thicker string. When the string is pulled tight it will work better and then you can then hear each other clearly .

Hypothesis:
We think that we will be able to hear better with the plastic string because when we first used the thin string, we couldn’t hear each other clearly. Since we couldn’t hear our voices properly, we think that the thicker the string gets, the better you can hear the other persons voice.

Procedure:
First we were given three strings, two pins and also two cups, and the ice blocks stick.
After collecting all of the equipment we needed to poke a small hole at the bottom of each cup that will be big enough to fit a very thin string into it.
Next we concentrated to put the string through the hole and tie the string to the ice block stick. Eventually we got it through without a struggle. After that we went outside and tested it out. We couldn’t really hear each others voices by speaking into the cup so we changed the string and attached a thicker string which was a rope.
We did the same thing we did to the thinner string and tested it out. This time we could hear each others voices clearer. My partner and I were onto the last string.

Results:
After following the instructions, we found out that we could hear better with the wool rope. We think that the reason for this is because the voice goes throw the string and it vibrates to the other cup .

Conclusions:
We learned that the vibrations travel through the string into the other side of the cup making the other person able to hear their voice. We also learned that you have to pull the string tight enough because if it’s crooked then the vibration won’t be able to travel.