How Do We Hear? Applying the Engineering Process Day 2

9 teachers like this lesson
Print Lesson


Students understand the engineering process by identifying design flaws and redesigning the product to address the flaws.

Big Idea

Using their newly designed "phones," students rediscover the engineering process as well as explore why their invention works, explaining how sound waves travel through solids.

Let's Collaborate

5 minutes

Today, our lesson is the capstone of understanding if our invention demonstrated how sound waves can travel through solid objects. This lesson supports the basic understanding that energy travels through different mediums, transferring it from one place to another. So, I decided that we needed to get ready to discuss our findings through thinking about the engineering process.

I began by asking students if they thought their inventions worked? Did your invention prove that sound can travel through solids? What else did you discover?

Students shared several things.

Reflecting on Our Work

25 minutes

To get students to really reflect upon their team effort to produce an invention that would transfer sound from one place to the next through a solid object, I pass out a collaboration worksheet that helps to guide them in their thinking. I ask them to get with their partners and begin thinking about the engineering process that they went through. To refresh their memory, I display the Five Steps SB File and briefly went over each step. I explain that the worksheet is based around these ideas and that I want them to reflect on their work process.

As they worked, I rove the classroom and visit groups to discuss what they were finding. This independent work time enabled students to discuss in depth what they had done the day before. I thought it was important to respond to the observations that my students' energy levels need to have outlets during investigations. There was a lot of excitement yesterday as they worked. Today, it is more relaxed and the reflection process can take place. 

Pulling It All Together

20 minutes

After they worked together to really examine their design, we came back to our desks for a whole class discussion and reflection. I wanted them to share what they had found after really examining their design. Explaining why they chose certain materials was key to understanding how they could prove sound waves travel through solids and that energy is transferred. Collaborating on our ideas helped support their learning.

As we discussed materials some students realized that a thicker and longer tube might work better. And when you listened into the cup , it made the sound louder. I asked if a  cup or funnel worked better and got different explanations. This was debated a little. One group had used a bowl and that worked well to listen with, but they noticed that talking into the bowl didn't work so well. Their "phone" was a one way device. You could only talk into the cup and listen to the bowl. 

I asked students,"What did you change?" Several groups had changed out parts. I had wondered about the large tin cans because I thought they would gravitate toward those. One group said didn't use the tin cans. They had tried them and didn't like how they worked. One group said that  they decided not to use the little cylinders even before trying them out. They were too small to receive the sound. I asked if they thought that certain shapes of the ear and mouth piece mattered?Cups  transferred better was one discovery. String was abandoned for straws across the board. Sound traveled better through the straws because there was "more space to move," as one student put it. Their thoughts flowed out easily about their discoveries and their conceptions of how sound travel strengthened through it. 

Wrapping It Up

10 minutes

After all the sharing and ideas flowed out and I had felt like all the questions had been answered and shared, I asked, "How do we know that sound waves transfer from place to place? What is our evidence?"

Students explained that talking into the cup and listening on the other end and hearing it through the other cup, bowl or funnel proved that the sound traveled through the object. The energy had transferred. 

I asked how engineering had helped them discover it? They talked about how they had to redesign an idea until it worked. It told them that this is how inventions work. The person tests the idea over and over, changing materials and design until they get the best product to solve a problem.