After looking at a bunch of instruments and hearing Mrs. Brinza play them, we began to recognize patterns among them:  all the high-pitched sounds came from the shorter things (bars, strings, tuning forks) and all the low-pitched sounds came from the longer things. A  student asked to do the stick-thing again, but this time, change the stick's length in lieu of the amount of force going into it. So that's what we did!

We saw some patterns we were thinking would happen, but wanted more specific data from the sound app (this one now changed the pitch, but kept the volume the same).  And here's what we found:

1.  The number of waves (back and forth motions) we saw increased in the same time period as the pitch got higher, and the converse was true.  Low-pitched sounds had fewer waves in the same time frame.
2.  The amplitude (height of the wave) stayed the same.

This amount of waves per second we defined as frequency...and we figured out that Hertz is the way to measure the number of waves in a second!

We used our stick/table/motion detector set-up to gather some great data the other day, and today we turned to another student investigation idea, using an app!

We used a volume app to see what happens to the waves when the volume increases and here's what we found:

We saw the following:
1. The height of the waves kept increasing as the volume increased.
2.  The number of waves per unit of time stayed the same.

We officially defined this "height" as amplitude, and this reference lets us understand that the volume was changing.  We're wondering what happens when the number of waves changes...we're thinking that's related to pitch since that's the other way we know sounds can change!

Early in our unit, students created a list of investigation ideas, and most recently, we decided to revisit them as our table/laser/drum experiment wasn't all that we hoped it would be.  Mrs. Brinza got her hands on a device that tracks motion and displays it in a graph.  Since we kept hearing each other say, "Vibrations cause things to move back and forth, back and forth," this seemed like a good place to start.

We set up the motion tracker to be in front of a wooden stick (made of pine) and we ran the tracker after we hit the stick with both a gentle and a hard push. We saw the differences in the graph.  

"But how is this relating back to sound?"

One student responded with, "We saw the light do things on the ceiling yesterday, like when we beat the drum hard we saw big jumps in the light, moving bigger distances.  When we beat the drum softly, we saw barely any jumps in the light.  This makes me things that louder sound make taller waves and softer sounds make shorter waves."

Well said, 6th grader.  Here are pictures of the actual data we collected over two 6th grade classes.

What would graphs of actual sounds of different volumes look like for us to compare to our motion graphs?  Hmmm.....great idea!

After exploring instruments and seeing that they all produced sound with some sort of back and forth "springy" motion, this got us thinking about whether everything that produces a sound is springy, too!


So with Mrs. Brinza's help, we set up an experiment to gather more evidence about this, since the class wasn't in agreement.  We also made a slow-motion video of the light to see if it really moved (as caused by the movement of the table).  Check out the video below.

We've still got some questions about these vibrations as they relate to louder and softer sounds, and many students are asking for some better sort of "collection of the vibration" with either a better zoom-in or some sort of app to see the difference in these vibrations.  Stay tuned!

We spent today setting up our Driving Question Board, knowing we had questions that stemmed from our consensus model we established yesterday.  We tried really hard to build off of each others' questions.

From there, we also created a list of possible investigations to do that could answer our questions...leaving Mrs. Brinza some work to do overnight!  Thank goodness some of these things are readily available in our school!

We agreed that we hear sounds because they come from somewhere (a source) and then they are received (hence the sound receiver someone coined).  However, we had lots of discussion about what is happening between the two. We recognize that the sound must move, but we weren't sure if the sound should be represented as a particle or not.  

So we put some sounds over a scale (Mrs. Brinza's phone, the class' smartboard speakers, and a student yelling), but none of them registered weight on a scale.  Because of this, we're thinking that sound can't be a particle, and instead must be a form of energy, since energy makes matter move...like heat from the sun makes the water particles move (we connected this back to fog!).  

We've got lots of things to think about, and we're starting to ask some great questions!  We're going to set up our DQB tomorrow focusing questions on the sound source, what happens with the sound as it moves away from the source, and then what happens to the sound receiver!  Stay tuned!

To launch our new unit, Mrs. Brinza shared a neat video she found online here.  We saw some pretty neat things from the video, which Mrs. Brinza documented:

We also spent some time developing our initial models about this phenomenon, which was super neat to see!  We'll be sharing out our ideas behind our models tomorrow.