This week in lunch lab we have been showing everyone how to use confuser phones and oven racks. The confuser phones are made of headphones tubes and bottles and the tubes are connected to the other side of the headphones. We had some challenges for everyone to do about sound like: they close their eyes and spin around and they have to point at the direction the sound was coming from. They guessed wrong because it sounds like the sound is coming from the left when it is the opposite direction. That happens because the tubes are crossed over.
The oven racks are only one ordinary oven rack with a string that you attach to the top and spoon that you hit the rack with. The objective with this experiment is to find out: what noise does it make if you tap oven rack when you have wrapped the string round your finger, and does it sound different if you put your fingers in your ears and tap the rack?
We discovered it does sound different because the vibrations travel differently to get through the string. It sounds deeper because the sound is vibrating through the string and not the air, and the deeper sounds vibrate better in the string.
We have also been doing string telephones in lunch lab. We got interested pupils to talk to each other from farther away by only using string and cups! We tried to use different techniques and see which ones work and which ones don’t. We tried bending the string around corners, which didn’t work because it stopped the vibrations so no one could hear each other. Vibrations are how sound travels through the air and in this case, through the string. We tested if it would work with the string dangly, and it didn’t work because, again, it stopped the vibrations from moving clearly enough. Then we tried crossing two of them over to get four people on one telephone at once, we thought that it would work because the vibrations should be able to travel through all of the stings, but to our surprise, it didn’t! The only way to get the normal string telephones working was to have two people on it at once and pull the string tight. The reason this works, is because the vibrations go through all the parts of it and we can hear it.
By Kye (yr 5), Leo and Wilfred (yr 6)