Guided Inquiry: Pendulums

For my guided inquiry experience this week illustrating the concept of momentum, I chose the question, "Which pendulum will come to rest more quickly, a lighter or heavier pendulum?"  Before actually carrying out the experiment,  basic information was gathered about simple pendulums. Many variables came into play. They ranged from the length of string, weight of the bob and the amplitude or angle or release.  Since the question pertains only to mass, the string and amplitude were the fixed variables.  The materials used in the investigation was a yardstick, a protractor, fishing line and the three washers from the science kit. Each washer was given three trials. Time was entered in a data table.  Results showed that the heavy washer came to a full rest  averaging around nine  and a half minutes after it's release. the light weight washer four and a half and the medium weight  washer close to seven minutes. The investigation, yet simple, demonstrated the concept of momentum and the objects having more mass, momentum increases.

What worked well or did not work well? The materials were  simple and readily available. the pivot point game me issues.  I first used a pushpin as the pivot point of the pendulum. There was a lot of movement at the pivot point causing the washers to fall off on several occasions. A thumbtack replaced the pushpin causing less movement at the pivot point. Modifications to the investigation might include changing the amplitude, arc, of release of the pendulum. "Will that cause increased momentum and therefore causing the bob to take longer to come to a complete rest?
 
Engaging  and relevance, two interesting vocabulary words. To understand pendulums better take the students to a  field trip to a playground with a swing set. Once there, the students observe their fellow classmates on swings with various lengths.  Observing  the different mass of each of the students and how that might affect the frequency and  period of the pendulum as well the arc or amplitude of release.  A totally different activity, if your principal or supervisor allow, is sledding. Children of different mass sledding downhill using different sleds.  There are many concepts and variables that come into play here, momentum, friction, gravity, etc. 

Specifically having the students understand and learn the workings of a SIMPLE pendulum, collecting and analyzing and the ability  to generate conclusions from that data. Challenging my students to come up with variables  affecting the period and frequency of a pendulum would be a goal in achieving further understanding of how pendulums work.