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Bone strength

By Diane Moore,2014-01-04 18:14
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Bone strength

    Context > Ceramics > Teaching and Learning Approaches > Bone strength

    STUDENT ACTIVITY: Bone strength

Activity idea

    In this activity, students create artificial bones made of paper to compare the relative strength of solid bones with hollow bones.

By the end of this activity, students should be able to:

    ; describe the main anatomical features of a large load-bearing bone like the femur ; compare the load characteristics of hollow versus solid paper ‘bones’

    ; explain the advantages of hollow versus solid in terms of bone construction.

Introduction/background notes

    What you need

    What to do

    Student worksheet 1 Basic bone anatomy match photos with correct caption

    Answers to student worksheet 1

    Student worksheet 2 Basic bone anatomy questions

    Student worksheet 3 Bone strength solid versus hollow

Introduction/background

    Hydroxyapatite minerals help to give bone its strength. The way bones are constructed also plays a part, for example, the main load-bearing bones of the body are not solid as one might expect but hollow.

    The long bones of the body like the femur (thigh bone) are hollow, and for most of the length of the bone, the cross sectional shape is a circle. This hollow cylindrical structure gives the bone added strength as well as reduction in mass.

    This activity compares the relative strength of solid bones with hollow bones. Instead of using real animal bones, artificial bones are constructed with A4 paper. The load-bearing capabilities of these bones are then compared.

    Before completing the hollow versus solid test, students will complete a preliminary exercise dealing with basic large bone anatomy.

What you need

; Student worksheets

    ; Sheets of A4 paper

    ; Sticky tape

    ; Cardboard box lid (A4 photocopy paper box lid is ideal)

    ; Supply of booklets or textbooks to act as weights

What to do

    1. Hand out copies of worksheet 1 and have students complete it. Discuss the results.

    2. Hand out copies of worksheet 2 and have students complete it. Discuss the results.

    3. Hand out copies of worksheet 3 and make sure students have the necessary materials.

    Have students complete the activity. Discuss the results.

? 20072010 The University of Waikato 1

    www.sciencelearn.org.nz

    Context > Ceramics > Teaching and Learning Approaches > Bone strength

    Student worksheet 1 Basic bone anatomy match photos with correct caption

    Cross-section shows compact bone with the

    medullary canal at the centre.

    Running through the middle of the bone is a

    hollow section called the medullary canal. It

    contains yellow bone marrow rich in fat.

    The butcher is using a band saw to cut the

    cow shinbone in cross-section.

    The butcher is using a band saw to cut the

    cow shinbone longitudinally.

    The outer bone layer is known as compact

    bone. It is a thicker around the middle part of

    the bone than at the ends.

    This cow shinbone is free of any attached

    tissue. Each end is known as an epiphysis,

    and the middle section in between is called

    the diaphysis.

    Within the epiphysal region, there is a region

    of spongy bone known as cancellous bone.

    ? 20072010 The University of Waikato 2

    www.sciencelearn.org.nz

    Context > Ceramics > Teaching and Learning Approaches > Bone strength

    Answers to student worksheet 1

    This cow shinbone is free of any attached

    tissue. Each end is known as an epiphysis,

    and the middle section in between is called

    the diaphysis.

    The butcher is using a band saw to cut the

    cow shinbone longitudinally.

    Within the epiphysal region, there is a region

    of spongy bone known as cancellous bone.

    The outer bone layer is known as compact

    bone. It is a thicker around the middle part of

    the bone than at the ends.

    Running through the middle of the bone is a

    hollow section called the medullary canal. It

    contains yellow bone marrow rich in fat.

    The butcher is using a band saw to cut the

    cow shinbone in cross-section.

    Cross-section shows compact bone with the

    medullary canal at the centre.

    ? 20072010 The University of Waikato 3

    www.sciencelearn.org.nz

    Context > Ceramics > Teaching and Learning Approaches > Bone strength

Student worksheet 2 Basic bone anatomy questions

    1. The terms longitudinal and cross-section are frequently used in the field of anatomy. With

    reference to the cow shinbone photos, explain clearly what these terms mean.

    2. What is the difference between cancellous bone and compact bone?

3. Where is the epiphysal region of the bone located?

    4. Where is the medullary canal located and what is its main function?

    5. The main shaft of the shinbone is hollow. Can you think of a reason for this?

6. Read the Science Ideas and Concepts article ‘Bone and tooth minerals’ paying particular

    attention to the bone structure diagram given. Describe in simple terms what compact

    bone is made up of.

    ? 20072010 The University of Waikato 4

    www.sciencelearn.org.nz

    Context > Ceramics > Teaching and Learning Approaches > Bone strength

    Student worksheet 3 Bone strength solid versus hollow

1. Roll up a sheet of A4 paper (short side to short side)

    into a hollow cylinder of 2.5cm diameter. Tape the roll

    top and bottom to hold it in place. Make 3 more.

    2. Tightly fold up a sheet of A4 paper to make a solid

    cylinder (5 folds, short side to short side). Tape it top

    and bottom to hold it in place. Make 3 more.

    3. Tape each of the cylinders into a corner of the

    upturned cardboard box lid.

4. Stand the lid on the four hollow cylinders on a table so

    that they will act as legs to support the lid.

5. Add weights (books, wooden blocks or 250g masses)

    ono the top of the lid until the legs buckle. Note the

    number/mass needed to buckle the legs.

6. Repeat this procedure with the solid legs.

7. Compare your results. What do you conclude? Can you

    think of a possible explanation for the result you

    obtained?

    ? 20072010 The University of Waikato 5 www.sciencelearn.org.nz

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