#12 The Skeletal System

Main Lesson Book
We began, of course, by reviewing the previous lesson, The Urinary System. Students completed their summaries and illustrations for their main lesson books.

Day One Story
We spent an entire week on the combination of the skeletal and muscular systems. For an introduction on Day One, I had Leah dissect her freshwater perch specimen (from our Intermediate Dissection Kit from Home Science Tools) during morning work time. Fish were the very first animal to evolve to have bones! Students were able to watch this dissection if they wished.

In the afternoon I read Bones: Skeletons and How They Work by Steve Jenkins.

Day Two Story & Exploration
I took my story for The Skeletal System from Linda Allison's book, Blood and Guts: A Working Guide to Your Own Insides.

The chapter is called "Bones and Body Plan: The Shape You're In." I required that the older students take notes during the lesson.

We started with pages 21 (Bone Dry?, Bone Hard), 22 (Bone Formation), and 23 (Amazing Facts). I searched pharmacies and hardware stores near me but was unable to buy 6% hydrochloric or muriatic acid. However, someday I would really like to do the Knot a Bone activity on page 23. If anyone knows of a source for these chemicals, please let me know!

Next we read page 24 (Kinds of Bones, Joints) and I got the Steve Jenkins book back out and we looked again at the full-size illustration of the human elbow joint. We did the Landmarks activity on page 25. Then we did the Inside a Long Bone dissection activity on page 27.

Next we read pages 28 (Body Plan), 29 (Primate), and 30 (Basic Vertebrate Shapes). We did the Make Your Own Flexible Spine activity from page 58 of The Human Body: 25 Fantastic Projects Illuminate How the Body Works. I highly recommend using empty spools of thread for this and having extra powdered sugar ready!

We also looked at my MRI from November 9, 2006 and I showed the students my disk bulge between L1 and L2. We talked about all different kinds of disk injuries including bulges, slipped disks, and pinched nerves.

Finally, we did the Make Your Own Joints activity from The Human Body: 25 Fantastic Projects Illuminate How the Body Works. This is really hard to do with floral foam (which was a disappointment since I had been waiting years to do this activity). I recommend only doing the saddle joint. We found it fine to cut the foam with regular dinner knives. I got dry foam cylinders from Walmart. The shape is called a "mug plug" and comes in a two pack (you need one two pack per saddle joint). They measure 2.6 x 3.7 inches.

Day Three Review & Exploration
We started by reviewing the saddle joint and looking at our model. This joint is located in only one place on the human body -- the base of the thumb -- and it's the reason your thumb is opposable. To see the importance of this joint, I had the students spend one hour doing the Great Thumbless Survival Test activity on page 30 of Blood and Guts.

After the hour was up, we discussed how it went. I had great fun watching a student play Yahtzee thumbless!

We reviewed the parts and function of the skeletal system by looking at the nomenclature three-part cards from ETC Montessori. I laid out and matched the pictures and definitions, and passed out the vocabulary cards to the group. As I showed each picture and read each definition, the child who had that vocabulary term came forward.

We also looked at the The Skeletal System page in our atlas of the human body, the Wall Chart of Human Anatomy.

Main Lesson Book
Students began to draft their summaries and illustrations for The Skeletal System.

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