Chapter 6: Movement (Comparing the strength of the compact bone with the hollow bone)

Content Standard: 
Support, movement and growth in animals

Learning Standard:
Carry out an experiment to differentiate the strength of compact bones with hollow bones.

Learning Activity:

Good morning students. Today we are going to compare the strength of the compact bone with the hollow bone by doing a simple and easy experiment at home. Before you do the experiment, let us see look at the characteristics of compact bone and hollow bone.

Structures of compact bone and spongy/ hollow bone

COMPACT BONE
Terrestrial vertebrates such as elephants have big, compact and strong bones. This is because the whole of its body weight is supported by the endoskeleton.

Compact bone

HOLLOW BONE
Birds have hollow bones to enable them to fly. Hollow bones have several advantages:
(a) light and strong
(b) allow the vertebrates to move more quickly
(c) need less calcium and phosphorus

Spongy/Hollow bone

Now you already understand the difference between compact bone and hollow bone. Now it is time to do the experiment. Before you start, watch the video below:

Video 1

Video 2

Exercise:

For today's exercise, each one of you need to submit an experiment report and ONE photo of you conducting the experiment TODAY by 4pm. Please refer to the experiment report format below.

Name: __________________
Class: __________________

Aim: To compare the strength of the compact bone with the hollow bone
Problem statement: Is the hollow bone stronger than the compact bone?
Hypothesis: The hollow bone is _____________ than the compact bone.
Variables: 
(a) manipulated: Type of cylinders (hollow or compact)
(b) responding: Number of textbooks that can be supported by the cylinders
(c) Length of the cylinder

Materials: A4 paper, cellophane tape, box covers
Apparatus: Textbooks, scissors

Diagram:

Model A

Model B

Procedure: 
1. Make a compact cylinder with a diameter measuring 2.5 cm. Stick the upper and lower ends of the paper roll with a cellophane tape. Make three more similar roles.

Diameter 2.5 cm

2. Stick each cylinder at the corners of the box cover and name the structure as table model A as in Diagram above.
3. Make a hollow cylinder with a diameter measuring 5 cm. Stick the upper and lower ends of the paper roll with a cellophane tape. Make three more similar roles.

Diameter 5 cm

4. Stick each cylinder at the corners of the box cover and name the structure as table model B as in Diagram above.
5. Place the textbooks one by one on top of each table model A and B until the paper rolls bend.

Result:

Cylinder	Number of textbooks that can be supported
Hollow
Compact

Conclusion: ________________________________________________
Questions: 
1. What is represented by:
(a) the paper rolls of table model A?
(b) the paper rolls of table model B?
2. Suggest two advantages of the support system that is represented by the paper rolls of table model B.

References:
1. Science Form 4 KSSM Textbook
2. https://diffzi.com/compact-bones-vs-spongy-bones/
3. https://www.youtube.com/watch?v=JoykM7EDwIE
4. https://www.youtube.com/watch?v=5fwUt3D21nE