# This Experiment focuses on the Center of Gravity of objects

Subject:

Science

6, 7, 8

Title – CENTER OF GRAVITY
By – Judy Schneider
Primary Subject – Science
Secondary Subjects – Science
SCIENCE PROJECT OF THE WEEK

CENTER OF GRAVITY – TWO PROJECTS
PROBLEM: Where is center of gravity located?

RESEARCH: Look up center of gravity in a physical science textbook. Write a half page report on the subject. Be sure to include information that was discussed in class.

HYPOTHESIS: Answer the question asked in the problem. How does the center of gravity change position.

MATERIALS:
Project I
cork or carrot
two forks
drinking glass
nail
Project II
cardboard
string
weight (washer, bolt, etc.)

PROCEDURE:
Project I
1. Insert the forks into a cork or carrot on opposite sides so that the forks stick straight out.
2. Balance the cork on the edge of the glass.
3. Describe where the center of gravity is located. Draw a diagram showing where you think it is located.
4. Change the position of the forks so that they are both angled downward.
5. Balance the cork on the point of a sharpened pencil.
6. Describe where the center of gravity is located and draw a diagram showing where you think it is located.
Project II
1. Cut the cardboard into a strange shape.
2. Punch a hole near the edge of the cardboard and hang it suspended from a nail.
3. Make a plumb line by tying a weight to a thread and attaching the thread to the nail.
4. Mark a line on the cardboard where the thread touches it.
5. Repeat steps 2, 3, and 4, in two more spots on the side of the cardboard.
6. Remove the thread from the cardboard.
7. Balance the cardboard on the end of a pencil. (How do you know where to put the pencil? Be prepared to demonstrate your center of gravity in class.)
8. Describe the center of gravity for the piece of cardboard.
9. Explain how this principle might help a tightrope walker in a circus.

DATA: Your data should include the following:
1. Research report
2. Diagram from step 3, project I
3. Diagram from step 6, project I
4. Answers to the questions in step 7, 8, and 9, project II
5. You MUST include the cardboard from project II – attach it to your report.

CONCLUSION: This is not optional. You must explain what you learned by doing this activity.