I Just Know It!

"I just know it" are words that no mathematician would ever utter. No, instead mathematicians must provide proof of their conjectures and generalizations about their math ideas that convince their peers they are correct. Mathematicians do this by having clear representations and multiple pathways to solutions, not just by being "good at math." In our classroom math is the authority, not status.

 Your fourth grade mathematicians are being asked to think critically about strategies for multi-digit addition and subtraction during this unit. They have shown different strategies for dealing with these types of problems and have discussed how some solutions are more efficient for certain problems. For example, we had a great debate about how you would solve 999+1,765. "Why would you go through all of the hassle to do the standard algorithm (regrouping) way?! It is SO much more efficient to just add 1 to 999 and take 1 from 1,765!"

This type of conceptual understanding of numbers and how they work is essential to developing into strong mathematicians. We must be able to think flexibly about how numbers work in order to find strategies that help us to be accurate and efficient. Then we need to be able to communicate, discuss, and represent those ideas to our fellow learners.

The kids know that I  love teaching math because everyday my mind is genuinely blown by the way that we can think differently about these concepts. I have told them my woes of workbook pages and procedures that I never understood when I was in elementary school and they remind me everyday that we never stop learning!

Stop That Sound!

This week we continued to investigate our sound energy phenomenon. We tested our original hypotheses around how sound waves travel, how sound is absorbed or echoed and how sound travels best through certain materials. 

By using tuning forks and water we were able to see how sound waves travel and determined that the singer had to have a great amplitude in order for the sound waves to be carried to the glass and break it. Then we used what we knew about matter and connected it to our inquiry task through a close reading activity. Mrs. Parker and Mrs. Eaton helped to further illustrate the students' ideas around how sound moves by having them act out how they would move if they were solid, liquid, or gas molecules. This activity lead us to the conclusion that the glass had to be empty for Jaime to break it. If it had water in it, the students thought that he would have to be at a much higher pitch or it might not have even broken at all.

Lastly, we thought about how sound is echoed or absorbed and tested an iPad sound generator in three different conditions: empty box open with lid off, empty box closed with top on, and a box with the generator wrapped in a material of the groups' choosing. All of the students chose to wrap their generator with cotton batting because they predicted that the sound molecules would have a harder time moving through the thick absorbent material. Their data was conclusive with this hypothesis and the decibel readings were all considerably lower when the batting was blocking the sound. This lead the scientists to want to watch Jaime again and they decided that he was able to break the glass even when he was behind a glass because it is a solid and the vibrations were still able to echo off of the material and break the glass. They wondered if he would've been able to break the glass if it had been covered in cotton!

Next week we will conclude our investigation and use our observations, new learning, and data to write a strong conclusion as to how this breaking glass phenomenon is scientifically possible. 

Stay tuned!