No, this is not new news, but with the Cicada fever taking over the Mid-Atlantic states of the. US, it is a great opportunity for the average person to gain a bit of an appreciation for the beauty of the mathematical world. My students are anxiously anticipating the emergence of Magicicada Brood II in the Bronx. We've been monitoring the soil temperature since returning from Spring Break, sampling from six locations in the school yard and calculating the mean temperature. Which, by the way, yesterday was a full 2°C above the cicada trigger of 17°C! My Science 4 group spent a period yesterrday surveying the tree trucks for nymphs and molts and the ground around them for emergence holes. Despite several false alarms, no positive signs yet.

Marcus du Sautoy uses the 17 yr Cicada as an example of the pervasiveness of prime numbers (and his favorite number) in Music of the Primes and Num8er My5teries. These are both regular resources that I use in my Math 5 Number Theory unit, so my 5th graders are excited to experience something they've already learned about, and it will be a wonderful first hand refence for my 5th graders next fall!

Recently, in response to #Swarmageddon, The New Yorker posted an article on the role of prime numbers in natural selection. Here's how I shared it with my students via our Edmodo STEM Forum:

As we have often explored in class, and will continue to explore through this forum, Maths are EVERYWHERE! I always say that the numbers have always been there, humans have only found ways to decode some of their mysteries through Maths. Most exciting, we keep discovering new Maths, new ways of describing and understanding the universe in which we live.

http://www.newyorker.com/online/blogs/elements/2013/05/why-cicadas-love-prime-numbers.html

## Saturday, May 25, 2013

## Tuesday, January 8, 2013

### 40 Million Times A Year

I sometimes find myself surprised by my students' response to lessons or activities. This week in my 4th Grade Math class I have been experiencing one of those times. I began the week of reviewing the multiplication algorithm with the following prompt:

While I expected some interesting discussion about how the set up the problem, I did not expect the incredible level of discussion before doing a single calculation. And not by just the one or two über insightful students, but by the entire class. This simple prompt to initiate practice of a mechanical skill with real data has turned into a incredibly rich investigation. My students have engaged the school nurse, as well as outside experts via Twitter.

After presenting the prompt above, my students launched into an animated half hour long discussion, considering a wide range of associated questions:

As the discussion started to wind down, I asked for suggestions of what to do. Again, the idea of findinsg a median resting pulse was suggested. Not by name, but in concept: "Some people will have a slower pulse and some will be faster. We need to figure out what the middle [pulse rate] will be." We arrived at a median resting pulse of 76 beats per minute.

For homework, I asked them, "How many times will your heart beat in 2013?" And that brings us to the title of this post. Take care of your hearts my friends, it is a busy muscle.

How many times does your heart beat?...in an hour?...in a day?...in a month?...in a year?...in your life?

While I expected some interesting discussion about how the set up the problem, I did not expect the incredible level of discussion before doing a single calculation. And not by just the one or two über insightful students, but by the entire class. This simple prompt to initiate practice of a mechanical skill with real data has turned into a incredibly rich investigation. My students have engaged the school nurse, as well as outside experts via Twitter.

After presenting the prompt above, my students launched into an animated half hour long discussion, considering a wide range of associated questions:

- how many times does it beat in a minute
- How do we know how fast it beats?
- It matters if you're exercising or still.
- It depends on what you're doing.
- It might matter what you're eating.
- If you're running it beats fast.
- It depends how long you live.
- The months have different numbers of days and there are leap years.
- Does gravity matter?
- Does your mass/weight matter?
- Does our heart slow down while sleeping?
- Does fatigue or dehydration effect it?
- Does age matter?
- The rate is always changing.
- We need an estimate.
- Does your height matter?
- We need to get resting pulse, then exercising, get an average, something in middle.
- We need a rate between the highs and lows.
- Everyone will have a different answer.
- Does respiration rate matter?

As the discussion started to wind down, I asked for suggestions of what to do. Again, the idea of findinsg a median resting pulse was suggested. Not by name, but in concept: "Some people will have a slower pulse and some will be faster. We need to figure out what the middle [pulse rate] will be." We arrived at a median resting pulse of 76 beats per minute.

For homework, I asked them, "How many times will your heart beat in 2013?" And that brings us to the title of this post. Take care of your hearts my friends, it is a busy muscle.

*The investigation has continued to build. I will share more in my next post.*

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