It's A Heartbeat Away

by Math4
(Teacher's note: this group is practicing the multiplication algorithm, multiplying multi-digit factors and working with multi-step applications of the algorithm.)

We came into the room on Monday morning and our teacher had this up on the board:

We then all started asking questions and sharing ideas about what might make our hearts beat faster or slower.

• 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
• depends on what you're doing
• might matter what you're eating
• running beats fast
• depends how long you live
• health condition might affect
• months have different numbers of days
• leap years...
• does gravity matter?
• does mass/weight matter?
• does our heart slow down while sleeping?
• does fatigue or dehydration affect?
• does age matter?
• rate is always changing... need an estimate
• does height matter?
• get resting, then exercising, get an average... rate between the two
• everyone will have a different answer
• does respiration rate matter?

We wanted to figure out how many times our heart would beat in a minute while we were sitting down. We thought this might be a lower number of beats because when you’re exercising your heart beats faster. We called this our resting pulse. We used this to calculate how many times our heart would beat in an hour and then in a day. Then we tried jogging around to get our exercise rate.
This got us interested in how gravity might affect pulse rates and what the differences might be for someone on the International Space Station. We tweeted some questions to space to get some more information. 

We learned that Suni Williams has the record for female EVA time (50hrs 40min). We wondered how many times her heart beat during those EVAs. Our school nurse came and talked to us about how our hearts work, how it beats, why it beats and some of the different things that make it beat faster or slower. We learned that when you are excited, your heart beats faster. Since Suni was out it space, she was probably pretty excited and maybe nervous or even a bit scared, so her pulse rate might be like our exercise pulses. 

When we measured our own pulses, we found that everyone had different rates. We decided to “average” our data and use the pulse that was in the middle of the class data. Our teacher told us that is called the median. Our median resting pulse rate was 76 beats per minute and our median exercise rate was 106 beats per minute. We used the median exercise rate to find out that Suni’s heart beat about 322,240 times during all of her EVA time!

We also got curious about pulses of other animals. We asked ISS National Lab what the Medaka fish pulse was. We decided to give the Medaka fish 85 days mission, the same length as CMDR Hadfield’s mission. The Medaka have a pulse of 116 beats per minute. That means their heart would beat 14,198,400 times during that mission!

Read more about the Medaka fish on ISS.

We also figured out that our hearts would beat about 39,945,600 times in 2013!

This was a lot of fun. It was a great learning experience. It was cool to learn about how many times our heart beats. It was fun learning about what could affect your heart. 

Try these experiments out in your classroom and see what you find. Write us in the comments section and let us know what  you learn.