Monday, September 17, 2012

Blood & the Heart Science Lesson

About this post
So I'm up to bat again for teaching at the beloved Co-Op (or 'coop' in our shorthand emails;^)). I chose Science- well, really, it chose me because I began to get all these random ideas of what I could excitedly teach the kids so I went with it. Never look an inspiration gift-horse in the mouth. Or re-invent the wheel...I'm happily recycling these LP's for our homeschool classroom, too. Even though Babygirl is in my coop class this time around, I think she can bear to hear it all again for the sake of her sister's learning.

So for the next seven weeks or seven posts, I will be sharing my lesson plans and class happenings with you in a slightly different format than the norm. Also, my target age range is 4-7 year olds. Bear with me. 


We had a fun discussion about the function of blood and the heart in the body in class. Here's a summary below of the most important points I sent home to parents for review.

We spoke about red blood cells (RBC's), white blood cells (WBC's), platelets & fibrin, and plasma. Then we made some red blood cells out of Play-Doh to get a sense of their shape. We rolled the 'Doh into a ball and then pinched it slightly between our thumbs and index fingers to get that nice, double-concave shape.

A Happy Trio, Wikimedia Commons
Allah designed blood cells this way to give them the max surface area for allowing as much Oxygen to latch on and ride on through the body while still helping the cell maintain a flat, portable, traffic-free shape for the blood vessels. To get the same surface area otherwise, they'd have to be a sphere. Sphere = not so portable and tend toward traffic jams through vessels/not enough cells getting through in time to deliver constant Oxygen supply.

  • RBCs are busy moving Oxygen around the body. They have a big job, get damaged and torn, and wear out after awhile. No worries, the body disposes of old ones and makes new ones every day in the yellow, goopy bone marrow and pumps them out into circulation (ha!)
  • WBC's rush to, attack, and wrap around and eat up things that try to make us sick (living germs and viruses). Confession: I (WBC) wrapped myself around a kid (germ/virus) and pretended to gobble them up in front of the class for a happy visual and some comic relief.
  • Platelets are involved in clotting. They block the exit of blood from the body if you're cut and keep things out, too until fibrin can come along and weave a net over the wound that we commonly call a "scab". It's the body's own band-aid.
  • All these things float around in a yellowish sea of Plasma.
  • How much blood?: Babies & little kids have less than a quart, big kids have less than 3 quarts, and adults have 5.5 quarts. I used a gallon pitcher marked with a dry-erase marker to show them what each quantity looked like. Alternative: I really wanted to use a bunch of zip-lock quart-sized bags with red-colored water in them but given my luck with anything that stains red and will spill (ie ANY liquid), I decided to play it safe since I had to transport everything I needed for class a long way. Insha'Allah, I will definitely do this at home with the daughters, though!

The Heart
We looked through "A Drop of Blood" for the great info and (microscope) images, as well as "Hear Your Heart". Both books are by Paul Showers and highly rec his books. (Thurs book rec?) 

Image of Heart via Heart Healthy 
We talked about Arteries (carry blood Away from the heart) and Veins (carry blood into the heart) and the size and shape of the heart muscle (your own personal fist-sized, not exactly shaped like a Valentine's heart). It pumps and squeezes constantly and never gets tires (Alhamdullilah!). Unlike their hands, which I had them hold up, open and squeeze tightly shut as many times as they could before they began to grow tired.

We did some exercises to get it pumping, practiced taking our pulses at our throats and wrists, and made a "stethoscope" by wrapping a toilet paper roll in construction paper to listen to it. Their amazement that it worked and they could hear a strong heartbeat only matched mine the first time I tried it myself.

Last, we did an activity on circulation that I *tried* to simplify as much as possible for them. It's a very complex process but as long as they understand the following, we're good:
1) The blood only flows one way around a healthy body (when it backs up or reverses is obviously when you will have problems), and that 
2) Blood gives Oxygen a ride and "drops it off" as it travels through the body. 
3)Then, the blood goes back to the heart and lungs to pick up more oxygen, only to be sent around to do more "dropping off" again and again. Hence the term "circulation".

1) Decorate their stethoscope (no time in class) and try it out on parents and siblings.
2) Take a flashlight into the bathroom and shine against the hand, behind the ear and into the mouth to see the red color of the blood running through their bodies.
3) Watch any (all!) of these animations online. *Preview them for your kids before showing in case they're easily grossed out- the heart can look kind of creepy in action but the scientist in me delights at things like this.
4) Coloring page on blood. I wrote out coloring key at the bottom of the paper. Click here to see a color image online. 

Cool links