1. Investigation 2 Joints Part 1 – Looking at Thumb Joints
Human Body
Investigation 2
Joints
Part 1 – Looking at Thumb Joints

2. For the Teacher – Getting Ready
Student Materials
1 Roll of masking tape
4 Student sheets no. 9 called Thumb Joints
Class Materials
Assessment Chart for Investigation 2

3. What We Will Learn
Articulated hands with opposable thumbs are essential for performing intricate tasks.

4. Science Vocabulary joint – the place where two bones meet.
articulated – jointed or joined in sections, as in the human skeleton.
opposable thumb – positioned opposite the other fingers.
immobilize – to prevent something from moving.

5. Review Bones How many different ways can you move your body?
What is the human skeleton, and what is it made of?
It is the hard internal frame of the human body, composed of about 206 bones.
What are the functions of the skeleton?
It provides structure, protection, and locomotion.

6. Questions
Where does your body bend?
Where two bones come together.

7. Focus on the Thumb
Move your hands and observe how the fingers and thumbs move.
Touch the tip of your thumb to the tips of each of the other fingers on one hand.
We can perform these movements because humans have an opposable thumb.

8. Focus on the Thumb
Opposable comes from the word opposite. So our thumbs are opposite our other fingers.
The ability to touch fingertips to thumb and to grip and hold objects firmly is one of the most important features of the human body.

9. Review Hand Joints Each hand has 14 joints. Can you find them?
How is the thumb different from the other fingers?
The thumb has only two joints; the thumb opposes the other four fingers.

10. Thumb Joints Student Sheet
There is a picture to color and a maze to trace on the Thumb Joints Student Sheet.
Read the list of everyday tasks with me.
This sheet describes tasks that you will perform, and that require movement of the joints in your hands.

11. Thumb Joints Student Sheet
Observe your joints carefully as you perform the tasks.
The catch – You are going to perform these tasks without using your opposable thumb.
It will be like working with your thumb removed or immobilized.

12. Taping Demonstration Watch me as I tape up someone’s thumb.
Be sure to cover the tip of the thumb with the masking tape.
Work with your partner to tape your thumbs.
Getters get the masking tape and a copy of the Thumb Joint Student Sheet from the materials center.

13. Thumb Joints Student Sheet
This is not a test to see if you can do the actions.
The purpose is for you to discover how difficult actions are without the use of your thumbs.
If you have difficulty trying to do a task, mark it as very hard and go on.

14. Discussion Which tasks were hard to do? What made them hard?
How did you solve the problem?
How did you feel when you ran into a hard task?
What are the advantages of an opposable thumb?

15. Science Vocabulary Review
joint – the place where two bones meet.
articulated – jointed or joined in sections, as in the human skeleton.
opposable thumb – positioned opposite the other fingers.
immobilize – to prevent something from moving.

16. Content/Inquiry
What is it like to perform everyday school activities without a thumb?
Thumbs are essential for performing everyday tasks easily.

17. What We Learned Today
Articulated hands with opposable thumbs are essential for performing intricate tasks.

18. What We Will Learn Tomorrow

19. Literature Connection
Your Amazing Opposable Thumb?