Day 3-4: Construction of Sound Amplifiers

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SWBAT: Follow a design and budget to construct their sound amplifer

Big Idea

Providing students with time to try multiple solutions to a problem helps model how engineers solve problems and demonstrates that perseverance pays off.

Distributing Materials

10 minutes

Material distribution strategy:

I like to have materials ready to go ahead of time, with the exception of tape.  I gather cardboard and cut it into 10 x 10 cm square, organize cups by size and set up a class store.  In order to "purchase" materials, students must present a detailed and neat sketch of their design and a completed budget before I "sell" them materials. 

Note: There is no actual exchange of money.  Students must opt for one of the 3 insurance policies at that time, as well.  I don't allow them to purchase insurance afterwards (just like real life).  I do allow groups who have remaining funds to purchase more materials, but they must present their budget to me to prove that they have enough money.  This works well and I have used the strategy for many other lessons in the past.

In terms of tape distribution, I have a meter stick taped to a desk near the class store.  I then measure the tape and have students roll it onto pencils or pens.  I have them put labels on their pens or pencils with tape that include their names and class period.  Leftover tape can be used to build another design--this minimizes waste and teaches resourcefulness.   

Build Designs

40 minutes

Now that students have their materials it is time to construct their first designs.  

I have the testing area set up in the hallway.  Controlling all sound is impossible, given our circumstances, so I have the kids do their best to test in the quietest environment possible.  

Some groups finish constructing rather quickly, so they are able to test out in the hallway.  Other groups may have more elaborate designs, which take longer to build.  As the educator, I have to anticipate these variations from group to group, while still maintaining order.  I suggest that you embrace the chaos.  Good noise isn't a bad thing!

The remainder of class is spent having kids construct and test designs.  Once they construct and test their first design, students go back to the design phase and come up with alterations or totally new designs.  They then complete a new budget and go through the process again.

Most groups have at least two designs.

Test Designs

1 minutes

Once students have finalized their construction, they have to collect data using the decibel app they downloaded to their phones.  This will require a controlled, i.e. quiet environment, so you might have to silence the class for a brief period of time.  As the teacher, you can determine what song and part of the song to play. 

Students should all play the same part of a song-- you can have them find one on YouTube to play. You may want to ask them, before telling them they must use the same song/same part, to consider what happens if they all test using different songs. (If they all play different songs then their decibel levels will be different, skewing the result.)  

Once they are done testing, students will resume building and the noise level can go back to conversation levels.

I used my smartphone and a tablet that I have access to in my class for each test.  I played the same song, "Call Me Maybe", for 37 seconds in each test.  We recorded the lowest and highest reading on the decibel app at during that time.  Additionally, we recorded the volume without the amplifier to establish a baseline reading (the control group).

Cleaning Up and Designating a Storage Area for Each Period

5 minutes

It is good practice to designate a storage area for each group and review clean up procedures prior to the chaos that ensues when clean up time actually arrives.  I like to place pieces of paper on shelves that have the name of each period on them.  I like to perform a call and response "clap - clap, clap, clap-clap-clap". Students respond with "clap, clap" to get students' attention and let them know that an important transition is about to take place or I have something important to share. This ensures that their hands are off their work and that they are looking at me and paying attention.

I then remind students where their materials and designs will be stowed for the night and how the room should look -- clean and organized -- and how it should look during the cleaning process -- calm and orderly.  I then allow them to finalize their thoughts within each group and they clean up.