Tug of War

Objectives:

To show that you can increse your strength with a pulley.

Time:

One classs period.

Materials:

Two broom handles
Long piece of rope
3 students

Prediction-Hypothesis-Question:

How can one person pull 2 strong resisting people together ?
PULL

Procedure:

Tell 2 students to hold broom handles about 2 feet apart.
Tell the class that you want someone to pull the 2 people together. They may only use the length of rope. WARNING they may not lasso each other. Have different people try moving the 2 students together.Share results.
Tie one end of the rope around one handle and then loop it over the other handle and back 5 or 6 times.
One small weak person can easily pull them together.

Record Results:

Have them draw what the poles and rope looked like when the 2 people were moved.

Conclusion:

Pulleys decrease the effort needed to do a job.
Go back to Machine Index