Julia+and+Hannahs+Clock+Experiment

=Clock Design: Simple Harmonic Motion= September 9th, 2009
 * Participants**: Julia Kravitz and Hannah Mollmark
 * 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]]

media type="file" key="Block 2; Spring Clock 2 and 3.wmv" width="300" height="300" Procedure: To begin making the clock, tie the spring onto a metal frame that will sit on the table. At the bottom of the spring, hook the 500g, 200g, and 20g weights. Pull the weights down until the 500g weight touches the surface of the table, then let go. After the weights come down to the table again, start the timer. Count the bounces, and stop when you get to the predetermined amount. Record and compare data. 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?
 * Brief Description Clock Design**: The clock we designed was a mass/spring system. It was 720g consisting of a 500g, 200g, and 20g weights. We pulled the spring down until the weight was touching the table surface and then released it. We started timing after one bounce in order to allow a regular, accurate timing procedure. We would count a predetermined number of bounces, stop the clock, and record the seconds it took to complete the bounces.
 * Specifications of Clock:**
 * Design Variables:** There are four main variables that we feel might affect the frequency of the system. One of these being weight. The heavier the weight, the slower the spring. Another variable would be how far down the spring is pulled. The farther down it is pulled, the faster it will travel. The size of the coil is another variable, the tighter and shorter the coils, the faster the clock will go. The last variable is the length of the spring. The longer the spring, the slower the clock and visa versa.
 * Studied Design Variable 1:** The first factor we studied was amount of mass placed on the spring. Different amounts caused the spring to travel at different speeds. The more weight the slower the spring traveled and visa versa. We experimented with this by placing different weights on the spring, both large and small amounts, and observing the changes in speed.
 * Studied Design Variable 2:** The second factor we studied was changing the size of the spring used. The results we observed from changing the variable showed that the tighter the coils of spring, the faster it travels. We maintained the same weight and number of bounces, so we know this change was a direct result of a different spring. The change varied from 1 to .59 seconds.
 * Lab Questions**:

In order to measure an event that lasts 60s, first attach 720g to the spring. This weight would be composed of 500g, 200g, and 20g weights. Pull the weights downward until the 500g weight is touching the surface of the table. Release the weight, and after one bounce (the weight returns to the table) begin counting. Count 60 bounces. This will put you within a second of 60s.

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 we studied that had the most significant effect on the frequency/period of the clock was the weight. If you observe the data table (shown above) that shows the difference in time between the weights, the change varies between .07 to 2.26 seconds. 20% of the weight we used (720g) is 144g so if we added that to 720g we would have 864g. If we were to use this weight, the new frequency/period of the clock would be about 3.2 seconds more. This is because I found that the difference in time between 630g and 750g (120g difference) was 2.17seconds and the 20g difference of 700g and 720g had a change of 1.12 seonds. I added these times together to get 3.2 seconds difference in a 140g change (this is close to the 144g added to our weight).

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.

Tthe variable that we studied that had the least significant effect on the frequency/period of the clock was the spring. The difference in time between the springs (shown in the data table above) varies from .34 to 1.12 seconds. Because we used a spring instead of a weight, this question is not applicable to our experiment.

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?

No, our clock design would not still be accurate for long time measurements. As the spring bounces for longer amounts of time, it begins to lose its pace and slow down. This is why it would not be accurate for the longer measurements. In order to improve the design of our clock to make it more accurate for longer measurements, we could have attempted to make it for longer measurements from the start. By this I mean that we could have tested for longer times. The slower times would not necessarily have been accurate because it would be compensating for the slowing down of the bounces in order to be accurate for longer amounts of time. We could decrease the amount of weight used in order to speed up the bounces, by doing this it would bounce for a longer amount of time and would be able to measure longer units of time.

Our mass/spring system experiment produced a valid and reproducible result. This is seen from the resulting data. We tested our system a number of times and recieved similar and fairly accurate results each time. Our experimental results differ from any accepted value because an accepted value would be more complex and more easily reproducible and therefore more accurate than just a spring system. Something would be needed to keep the spring moving at a constant rate and make sure that the spring moved at the same speed every bounce. Our experiment could have been improved by making sure that the spring is released at the exact place every time, instead of assuming a similar place is being used. In addition, the location of the weight when we begin timing (in experimentation stage) needs to stay the same to ensure accuracy and reproducibility. This is because a simple alteration can affect the experiments' results.
 * Conclusion**:

>> >> //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:**//independently//
 * 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?