InterActions in Physical Science

Examine the class graph. To see if there is a pattern, try drawing the best smooth line through the points representing the washers. (The line does not need to be straight; it can be curved.) As the length of a pendulum increases, what happens to the number of seconds it takes to make 10 back and forth swings?

1. Write your conclusion on your record sheet.
2. In looking at your class graph, you may have noticed that some
points (positions of washers) were above or below the smooth line
you drew. Why do you think not all of the class data points ended up
on a smooth line?

Participate in a discussion about what can be concluded from the class graph and the answer to Question 2.
3. Look back at the hypothesis you made at the beginning of the activity. How has your thinking changed after collecting data in the experiment?

Comparing your thinking now with what it was before is part of the process of being aware of and monitoring your own thinking. That is the skill you have been practicing in this activity.
4. Imagine that two teams each measured the time for 10 swings using pendulums. Each team calculated its best value and uncertainty.

Team 1: Best value was 20 s with an uncertainty of 1 s.
Team 2: Best value was 21 s with an uncertainty of 1 s.

Unfortunately, the teams forgot to write down the lengths of their pendulums. Since the best values were different, can you conclude that the pendulums of the two teams were different lengths? Explain your thinking.

discussion balloon

Participate in a class discussion about the answer to Question 4.

My Ideas

The key question for this activity is:

What is the relationship between the length of a pendulum and how long it takes to swing back and forth 10 times?

Are you satisfied that you now know the answer to the key question?
Explain.