In order for students to really understand how sound waves travel and transfer from place to place, I decided that this lesson would be two days in order for them to really absorb and process their understanding. In order for me to understand what students know about hearing and how our ear receives sound waves, I asked them to sketch their ear and how they think it works. I gave them white drawing paper and asked them to use colored pencils to draw how they think their ear works when they hear a sound. I instructed them to label parts of the ear and write an explanation of their drawing. I explained that I wanted them to start their explanation with an "I think" statement. In their explanation, they needed to include how they think a sound can be loud or soft. And finally, how does your ear know how to distinguish high and low sounds?
We laid out the drawings around the perimeter of the room. I asked them to take notes on anything they thought was different and more exact than their drawing. I wanted them to consider the possibilities of other people's thinking and impressions. I roved the classroom and discussed what impressions that my students were getting from looking at the drawings. As I roved, I asked questions like: What did we notice? What was unusual or different from their own thinking? One student remarked that his friend added the brain and he thought that was important. As they were explaining the ear to me, I could see how the next steps of this lesson would help solidify their understanding of how the ear works.
To settle the class down and to add to the appreciation of how we hear, I showed them a very special clip of a seven week old baby who hears for the first time. The room was absolutely still and then comments about the baby smiling started to emerge. I explained that while the baby cries instinctually, hearing was essential for the baby to speak words and that we learn phonemes, or our smallest sounds because we can hear. Students were ready to discuss their drawings as I proceeded with the questions.
After they were finished, I asked them to keep their drawing, set it aside and watch this clip about how the ear actually works. I asked them to look back at their drawings and share what parts fromt he clip they had included in their drawings. This way, they understood that their understanding was partially correct and that the video completed their understanding with more facts.
Connection of Prior Knowledge:I asked them how they think the eardrum hears? One student said that she first heard about it from a friend whose eardrum burst from an infection. Another student said that a cartoon was the reason she knew about it. We discussed the importance of treating ears gently, not putting things in our ears and I asked if seeing how the ear works helps them understand why putting a Q-Tip into the ear could create serious damage. After all the sharing, I explained that often we understand how something works from what we observe or experience, but that knowledge is key to understanding true facts. It was now time to move ahead and experiment some more with sound!
Objective: Students study how sound is transferred using a device using chosen materials. I gave my students choices of building materials to produce the best "telephone" possible with the materials provided.
A supply of these suggested materials:
wire cut in 3-4 foot lengths
string cut in 3-4 foot lengths
yarn cut in 3-4 foot lengths
I started this portion of the lesson with having them think about how sound travels through a solid object by having them place their ear on their desk and then tap it. I asked them to increase the force. What did they notice?
I told them that today we would explore this Driving Question: How can we prove sound waves travel (transfer of energy) through a solid object by using a model?
Then, I paired them up with appropriate partners who work well together and told them that they need to come up with a way that they can prove that sound waves travel through a solid object and transfer the energy by creating a device that they can talk through and be heard. I told them that they could any of the materials I had laid out except that they could not use more than two cylindrical objects. They could use combinations of different cylinders. They could use a cup with a funnel (cone), two funnels, or two cups, but not more than that. (This was partially due to the fact that I was limited on my funnels!) But, they were were welcome to use any of the other objects in combination or change anything that wasn't working as they created their device.
I reminded them that it was important to use care in working as a team and discuss their ideas as they planned. They began!
As students began gathering their materials, I could hear the plans being shared between the pairs. Some returned items and some gathered more. I roved the classroom to see what was going on. I asked students, "Why do you think this works?" could see combinations of different things, but the straws seemed to be the favorite "in between" piece. Experimenting, playing, listening and trying ideas were the key focus on this part the lesson. It was truly exploration and through this experience they quickly understood that choosing the correct shape of the cylinder made a difference, as well as what materials needed to connect the two pieces. I noticed that no one chose the small plastic film containers, nor the two large tin cans. I asked one group why they had brought back the tin cans ( I was thinking this would be the first choice to stick with), they shared that they didn't think the large cans were easily held, but probably "contained a lot of sound but lost the sound." These remarks made me understand that there are some misconceptions about how our ear works and how sound travels.
So, as students progressed I could see that they had understood the engineering process of trying to make their "phone" work at its best. This would be the key to them understanding how the transfer of energy works with sound and how we receive that sound. After twenty minutes things slowed down. They were ready to present and share their ideas.
I gathered everyone in a circle with their new "phones." Students shared how their "phones" worked and I let them talk about them. They were excited about them. They expressed that it was a fun experiment. I explained that we were going to return to it tomorrow, but with a different perspective. I told them that tomorrow we would examine the engineering process they had practiced today and start to think about and compile the scientific process they used to solve a problem and prove a phenomena.