Sound
Lesson: Science
Year 4 are learning all about sound. We started the topic looking at what sound looks like and how it travels. Everyone tried to draw a sound they heard that day and write a few things they THINK they know about sound. We have also tried to think about the questions we want to answer over the topic.
In our second lesson we investigated how sound travels. We learnt that sound travels through vibrations between small particles. We learned that sound travels through the air, glass and water but that it can't travel in a vacuum (such as space). To understand these complex ideas we acted out the interaction between particles so we could see how a sound is transferred. We also examined how helpful our hearing is and how we have evolved the ability to identify where a sound has come from.
In our third lesson we looked at how we could classify and group sounds. We had a lot of fun trying to make loud and quiet sounds using a decibel meter and then went off around school to capture different loud and quiet noises. Take a look to see how we got on and what noises the class thought were loud and quiet.
After learning about each state of matter, we asked ourselves whether sound would travel through the air better than a solid. To test this, we made a prediction and set about making some string phones. We chose to make three 20m phones and three 40m phones. Being the creative class we are, we decided that measuring out each string would be very boring, so we measured the length of the classroom and ran the string in lengths. Sadly, we did not foresee that groups would start to ball up the string and we were left with a great mess of tangled phone lines. How long is a piece of string? Too long with that many tangles... However, as good scientists we went back to the drawing board and were able to make each phone out on the field the next day. We discovered that sound travelled best along the solid despite only three members of the class making that prediction. We ended the lesson looking at a slinky which was able to show how vibrations travel across a space. This would definitely be a good lesson to try at home!
In order to gain more practical experience, a series of mini experiments were set up in the classroom. The children were asked to make observations and use their knowledge of sound to explain what was happening. One activity was researched based. The children had to use the internet to find what objects made different noise levels. Two experiments were based on pitch. In the straw experiment, the children had to observe what happened to the noise a straw made when they cut it. In the band experiment, the children had to see whether the thickness of a band affected the noise it made. When using the coat hanger, the children had to see whether sound travelled better through a solid or through a gas. Finally, the tuning fork and drum experiments tested the classes understanding of vibration.
Our final investigation was muffling. The class were given a set of materials which they could use to muffle an alarm clock (something to help them in later life). However, we found that alarms were designed well and that most of our materials weren't up to the task. After conducting one experiment, with mixed results, we tried to develop our experiment and conduct a large class study to compare different materials. It was clear that fabric did the job best so at least we know that, if we don't want to be disturbed, we should wrap our alarms in clothes if we want to lie in!
To end the unit, we spent time thinking about the questions we had asked at the start of the unit. We thought about which sources of information we could use and how to phrase our questions so we could find right answer. Take a look to see what we found out.
