Can You Hear It Now? Engineering Cheap and Effective Sound Amplifiers for Smartphones (2-3 Day Lesson)

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SWBAT: 1) Hypothesize, design and test ideas that lead to the loudest amplification of sound while music is playing from your smartphone 2) Analyze and use data to support your inferences

Big Idea

Engineering is often left out when teaching STEM classes. Students have seen how inquiry can be used to help explain phenomena that are backed by evidence. This challenge gives students the opportunity to incorporate their inquiry skills to solve a need.

Pre-Lesson Homework Assignment

My school has a relatively open policy for Bring Your Own Devices (B.Y.O.D.) for in-class use.  Granted, not all students will have access to Smartphones but that shouldn't dissuade you from doing this assignment--you only need one phone per group.  I would definitely suggest assigning the role of 'phone handler' to the person who owns the phone for each group.  If you find that many students in one group have phones, while other groups have no students with phones, then simply rework the groups so that there is one person with a phone in each one.

Another solution: If you own a Smartphone and have a tablet device, you could have a testing station in your room where students could insert the phone to play the music and the tablet can be used to record the decibel levels.  Note: A quiet space will be required for this--controls are important; great teaching moment to have with students.

Obviously, check with your administration and parents prior to doing the activity.

The phones don't have to be fancy, they just need to play music.  An iPod touch would work great, too.  Anything that has external speakers.

From a scientific control standpoint--not all speakers are created equal, so you will have students perform a baseline test without any amplification devices attached and then calculate the percent change--great math tie in--once their designs are being measured.

PRE-CLASS HW ASSIGNMENT: Have students download the following FREE Apps depending on what type of phone they have.  You may want to figure out how many students in each class have phones about a week in advance.  Give students more than enough time to download the apps.  Also, make a list of students who have phones.

iPhone owners should download this link

Android users should download this link.

Introducing the Need or Problem

5 minutes

Introducing the problem or need is your chance to grab your students' attention and get them to buy into the activity.  Make this time fun and exciting, maybe somewhat mysterious, if the behavior allows.  For this activity, we can get kids to buy into the idea of amplifying their smartphone by saying that we are going to have a dance party!  Teachers can then take out a Smartphone and start playing music directly from it.  Be funny.  Say something like, "Don't you looooooove this song, [insert student's name in the back of the room]?"  They will quickly realize the significant need for amplification and therein lies the problem -- how can we design and create a simple, yet effective, sound amplification system for our smartphones using basic materials?

Before you let students get started with designing their solutions, you should go over the expectations for the activity and how they will be assessed.  Hand out the description and review with the class.

Explain that, just as engineers, we too will be following the engineering design process during this project.   Remind them that it is really important that they record all data, major or minor alterations to their designs and any other information that might be useful in later stages.  

Note: This lesson will only be implemented if there are no significantly hearing impaired students in my class.  Equity is important in education and we certainly don't want to alienate students based on physical impairments or disabilities.  

Constraints and Budgets

10 minutes

Regardless of where they work, all engineers face constraints that inhibit their ability to create the most efficient and awesome solution to a problem.  Students can experience the reality of constraints through the implementation of a budget.  

Prior to students designing solutions, you must provide them with a list of materials and how much each one costs.  Hand out this budget sheet after you have gone over the rules and how students will be assessed, otherwise students won't listen and you will be answer many questions that were already reviewed.

Now that you have them really excited to get started, show them this rubric so that they know the expectations for the activity.  Important topics to convey to students, include: 1) All information, thoughts, data, etc. must be recorded in each student's science notebook--everyone must record their findings.  Why? It is helpful if someone is absent the next day and some reflection work will be done at home, so everyone needs the information and 2) Safety and respect for other peoples' property.  Phones are expensive and students' hard work needs to be respected.  This is especially true when designs are stored in and around the room.  Stress the importance of respecting others' work, just as they would like their property to be respected.

Designing Solutions

30 minutes

Give students ample time to sketch solutions to the problem.  I like to use the following strategy to make sure that everyone's voice is heard and that materials distribution is efficient:

Strategy to ensure all students are being heard:

1) Ask students to create at least 3 solutions, reminding them to look at the budget and materials sheet.

2) Each student shares their solutions with their group and students comment about what they liked and are concerned about in each design.

3) After each student has presented, groups either adopt a design to try or create a totally new design based on several students ideas.

4) They must then fill out a budget form and bring to me and I distribute the materials to them and they begin to construct their first prototype.