Clock+Lab+Report+(Stephanie+&+Aaron)

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


 * Participants**: Aaron Locke, Stephanie Morse
 * 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]]

The clock itself is a 20 cm spring attached to a piece of string that hangs from a metal frame. Attached to the spring is 580 grams of mass. The string that connects the spring to the frame should be no more than three centimeters to avoid the mass hitting the table on descent. To start the clock, pull the weight down until it is even with the tables surface. Release the weight and begin timing. One cycle which equals one second is a complete bounce from starting at the table, going up, and then ending back at the table. Count each cycle as one second to keep time.
 * Brief Description Clock Design**:

Procedure: (seconds) || Pendulum Time (seconds) || Mass (g) ||
 * Specifications of Clock:**
 * 1) Select a medium weight with a medium type spring as a starting point.
 * 2) Use a stopwatch and time for 10 seconds. During these ten seconds, count the amount of cycles (bounces) the homemade clock goes through.
 * 3) Observe results. If the homemade clock has more cycles than seconds, increase mass, which will decrease frequency. If the homemade clock goes for less cycles than seconds, decrease mass, which will increase frequency.
 * 4) Repeat steps 2 and 3, until your homemade clock and the timer are within 10% of each other.
 * 5) Continue with the weight that works, and test it at different time intervals. (10, 20, 30, 40, 50, 60 sec)
 * 6) Observe results. If the times are not consistently within 10% of each other, look for causes of error. (i.e. human error, not bouncing straight up and down, etc.)
 * 7) Record times. Create graphs.
 * Stop Watch Time
 * 10 || 0:10:19 || 580 ||
 * 20 || 0:20:30 || 580 ||
 * 30 || 0:30:12 || 580 ||
 * 40 || 0:40:33 || 580 ||
 * 50 || 0:50:77 || 580 ||
 * 60 || 1:00:20 || 580 ||

We believe that the two variables in this lab are mass and the type of spring used. We predicted with mass that a larger mass would me a slower time, and a smaller mass would be a faster time. With the spring, we predicted that the tightness or resistence of the spring would be the deciding factor. So, if a spring is very resistant the mass will bounce faster, and if a spring is not very resistent it will bounce slower.
 * Design Variables:**


 * Studied Design Variable 1:**

The first variable we tested was different masses. We used five different masses, but keeping one thing constant, the amount of bounces. We would count off 20 bounces and see how many seconds it took to get to 20. The graph and table below represent the date we collected.



The second variable we tested was the spring. We used two different springs, and kept the mass at a constant of 580 grams. We used two different springs. One spring at 58 cm and very resistant and one at 22 cm and medium resistant. We used the 580 grams and counted off 20 bounces (like before) and timed to see how long it would take with different springs. Tables below.
 * Studied Design Variable 2:**


 * Mass (grams) || Time (seconds) ||
 * 580 || 0:9:19 ||
 * 580 || 0:9:53 ||
 * 580 || 0:9:72 ||
 * **Average** || **0:9:48** ||

We did not use a graph for this variable because it was unnecessary.
 * Mass (grams) || Time (seconds) ||
 * 580 || 0:17:51 ||
 * 580 || 0:17:35 ||
 * 580 || 0:17:52 ||
 * **Average** || **0:17:46** ||

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? //Our device could be used to measure an event that lasts 60 seconds quite easily. With a mass of 580 grams, attached to a predetermined spring and string, can be pulled down so the length of spring and weight is 30 cm. When the mass is released, one cycle translates to one second. (i.e. the mass bounces up then down, then up again). Counting each bounce as one second, can accurately keep time for at least 60 seconds. The precise accuracy of the device can be found by following the percent accuracy. See work below.
 * Lab Questions**: Write out and answer any questions that are included as a part of the lab.

60 - 60.2 = -0.2 -->// -0.2 / 60 =//-0.0033// --> //-0.0033 x 100 = -0.33 %//

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 on our clock without a doubt is the mass. By looking at the data it is apparent that the more mass there is the longer it takes for the pendulum to go through one cycle, for example at 100 grams it took 8.53 second for the pendulum to go through twenty bounces where as at 400 grams it took 16.89 seconds to go through twenty bounces. If we were to increase the mass by twenty percent than the new frequency of the clock would be approximately 63 bounces per minute. I found this by calculating the average increase in number of bounces when adding 100 grams of mass and added that number to the average number of bounces per minute of the pendulum at 580 grams.

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. Out of the two variables we tested the one that had the least significant effect on the frequency of the clock was the length of the spring. Unfortunately my partner and I were only able to test two variables so to say that the length of the spring had the least effect on frequency does not mean that it did not have an effect it just means that it did not have quite as big as an effect as our other variable did. If we were to increase the length of the spring by twenty percent than the new frequency would be approximately eleven seconds per twenty seconds.

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? If our clock was required to keep accurate measures of time for up to fifteen minutes our clock would not meet the requirement. This is due to the fact that the spring that the pendulum is attached to loses energy after every bounce, therefor becoming slower and it would eventually stop after a couple of minutes.If we were to make the clock accountable for larger amounts of time we would have to find a way to keep the bouncing of the spring consistent for several minutes.


 * Conclusion**:

This project, which was designed in hopes that we could create a system that could accurately keep time for 60 seconds. The experiement was not all that hard to design. In order for the experiment to produce valid results repeated testing was necessary. By repeating the experiment and keeping time a constant, then adjusting the mass accordingly. By repeating the experiment many times, we came up with reproducible results that had less than a 10% error, actually, it had less than a 2% error. As seen above, we tested the mass of 580 grams at different times for 10 second intervals. Each time that we recorded was within 2% error. It is understandable for our clock to register the exact times that the stop watch did, because it would be nearly impossible for a pendulum to count milliseconds like a stopwatch. That is the most probable reason for why the experimental results will differ from accepted valumes. An improvement for this experiment, as with any experiment, is further testing. Testing with more exact weights or finding a more exact place to count as a cycle could be improvements. Sources of error include errors with starting and stoping the stopwatch on time and counting the cycles more accurately.

> > //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?