Michael+Trevor+Lab+1

=+Clock Design: Simple Harmonic Motion= Date of Publication (Date of Most Recent Edits)


 * Participants**: Michael Bateman & Trevor Wood
 * Purpose**: The purpose of this lab is to design and characterize a clock that is makes accurate time measurements in the range of 30 to 90s.
 * Lab Documents**: [[file:Simple Harmonic Motion.doc]]


 * Brief Description Clock Design**: The clock that Trevor and i designed uses the pendilum design. The 100g bob was on a 19cm string. There was a post that supports the pendilum that was 7 2/10 cm away from the fulcrum. To start the clock, you hold the bob even with the back side of the post. Once you let it go, the bob will complete a full period in a second. here is a video of our clock.media type="file" key="Block 2; Pendulum 1.wmv" width="300" height="300"


 * Specifications of Clock:** The tests were preformed by timing the release of the bob and counting as it completed each full period. When the pendulum completed its designated number of swings we would stop the timer and write and analize the data in a chart. We then turned our chart into a graph.[[image:string_length.JPG]]


 * Design Variables:** In a pendulum, there are two main parts, and three main variables. The two parts are the string and the bob, the three main variables are: the string (length), angle released from, and the bob (mass). We changed the string length to get our time dialed in to 1 period/second, after we had that all done, we changed the mass of the bob to see what would happen.
 * Studied Design Variable 1:** The factor we used to dial in the periods to 1 period/second was a combination of the angle and string length, because it seemed to have a more dramatic change. Ran a pole perpendicular with the ground, and we started the bob from the pole each time, so as the rope got shorter, the drop angle got greater. [[image:swings_per_second.JPG width="752" height="477"]]
 * Studied Design Variable 2:** We changed the mass of the bob, we found as the weight got lighter the faster the periods accured.
 * Lab Questions**: Write out and answer any questions that are included as a part of the lab.


 * 1) **Describe in detail how your device may be used to measure an event that lasts 60s. What would the accuracy of this measurement be?** To start our clock, you let go of the bob right as the time period starts. You count 1 full period for each second. In a 60 second time period, the clock is up to .5 second accurate.
 * 2) **Which variable that you studied had the most significant effect on the frequency/period of the clock? If you built your clock with a 20% increase in this variable, what would the new frequency/period of the clock be? Support your answer by referring to data in your report.**The variable that had the most significant effect was the length of the string. If the clock's string was increased by 20% the clock would have a longer period.
 * 3) **Which variable that you studied had the least significant effect on the frequency/period of the clock? If you built your clock with a 20% increase in this variable, what would the new frequency/period of the clock be? Support your answer by referring to data in your report.**The variable that had the least significant effect was the angle that the first drop was from. If the angle had a 20% increase the period would be longer but would not be effected as much as the other variables.
 * 4) **Though it was not a project requirement, it would be nice if your clock could also measure much longer times, on the order of 10 to 15 minutes. Would your clock design still be accurate for long time measurements? What might affect the accuracy of the clock for these longer measurements? Can you think of a way to improve the design to make the clock more accurate for longer measurements?**Our clock would not be extremely accurate up to 10 to 15 minutes. Our clock would lose momentum after a long period of time such as 15 minutes and its accuracy would be thrown off. The design of our clock could not be improved in this situation to work for this long of a period of time. Our string is too short and would eventually stop or the periods would become way to short to be accurate.


 * Conclusion**: A good conclusion will include:
 * The clock we produced is capable of making a reproducible result, because we had it swing at 1 period/second on day, then took it down and we got it to swing at the same rate the next day. It works for any time interval up to 90 seconds.
 * Our results were almost dead on, only .5 second off on 60 second interval, and that could be due to human error.
 * The pole we used to swing the weight from sometimes got hit by the bob on the way back from it's 1st period. if we started the bob from the front of the pole, this would not happen.

> > //Don't forget to link to your lab report from the lab reports page and to include a link to your lab report in your reflection.//
 * Independent reflection:** One lab report will be turned in for each group. In addition, each student must complete //independently// a reflection addressing the following questions:
 * How was the process of designing and testing a clock similar to the scientific method as discussed in class?
 * How did it differ?
 * What "steps" in the scientific process were present and which were missing?
 * Was there a part of the activity that is not a part of the scientfic process?