IA physics
Raymond Ye
Mr. Pettibone
IB Physics
2 November 2013
Internal Assessment
DESIGN
Aspect 1:
How does the time a rubber band spends stretching a force of 12.5 N affect the force required to break/snap the rubber band?
IV- The time spent stretching the rubber band 12.5 N
DV- The force required to break/snap the band
Units for Independent Variable- Minutes
Units for Dependent Variable- Newtons
Aspect 2:
Variables that will be kept the same include:
-The force of the stretch
-Conditions in room in which rubber band is stretching (variations are incredibly limited)
-Way in which the rubber band is being stretched
To accurately set the Independent Variable, I used an iPad app that allowed me to set multiple stopwatches at once. This is accurate and only deviates within 1 or 2 seconds depending on how slow or fast I take off the rubber band. With an experiment like this however, 1 or 2 seconds of extra stretching are arbitrary.
The way I measured the Dependent Variable was reasonably accurate. I hung a bucket on the rubber band that was stretched and SLOWLY poured water into the bucket until the band would snap. Once it snapped, I would immediately stop pouring water and weight the bucket. I proceeded to multiply what was displayed by Earth’s gravitational acceleration to find the force.
Aspect 3:
Schematic-
Picture of Experimental Setup
Procedure
1. Find 13 rubber bands of similar size and elasticity
2. Use bucket and slowly add water (if necessary) to snap a rubber band that has yet to be stretched
3. Weigh the bucket and all of its contents and multiply by Earth’s gravitational acceleration to find force.
4. Record Data
5. With remaining 12 rubber bands, progressively stretch for longer and longer periods of time (1 rubber band for 5mins, 10mins, 15mins,…60mins).
6. After they have been stretched for whatever amount of time, repeat steps 2 through 4.
7. Repeat steps 1-6 two more
Mr. Pettibone
IB Physics
2 November 2013
Internal Assessment
DESIGN
Aspect 1:
How does the time a rubber band spends stretching a force of 12.5 N affect the force required to break/snap the rubber band?
IV- The time spent stretching the rubber band 12.5 N
DV- The force required to break/snap the band
Units for Independent Variable- Minutes
Units for Dependent Variable- Newtons
Aspect 2:
Variables that will be kept the same include:
-The force of the stretch
-Conditions in room in which rubber band is stretching (variations are incredibly limited)
-Way in which the rubber band is being stretched
To accurately set the Independent Variable, I used an iPad app that allowed me to set multiple stopwatches at once. This is accurate and only deviates within 1 or 2 seconds depending on how slow or fast I take off the rubber band. With an experiment like this however, 1 or 2 seconds of extra stretching are arbitrary.
The way I measured the Dependent Variable was reasonably accurate. I hung a bucket on the rubber band that was stretched and SLOWLY poured water into the bucket until the band would snap. Once it snapped, I would immediately stop pouring water and weight the bucket. I proceeded to multiply what was displayed by Earth’s gravitational acceleration to find the force.
Aspect 3:
Schematic-
Picture of Experimental Setup
Procedure
1. Find 13 rubber bands of similar size and elasticity
2. Use bucket and slowly add water (if necessary) to snap a rubber band that has yet to be stretched
3. Weigh the bucket and all of its contents and multiply by Earth’s gravitational acceleration to find force.
4. Record Data
5. With remaining 12 rubber bands, progressively stretch for longer and longer periods of time (1 rubber band for 5mins, 10mins, 15mins,…60mins).
6. After they have been stretched for whatever amount of time, repeat steps 2 through 4.
7. Repeat steps 1-6 two more