Ryan+and+Marissa's+Awesome+Clock+Lab

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


 * Participants**: Ryan Payne and Marissa Marton.
 * 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**:

For our clock design, we used a spring attached to a string. This string was then attached to a metal frame. We then tested different weights by attaching them to the bottom of the spring and we counted how many seconds it took for a spesific amount of bounces in the spring. Initially, we started out with 500 grams. To start, we would pull the weight that was attached to the spring down until the base of the weight was touching the table. Then once we let go, we would let it bounce once and when it came back down to the bottom, we would start the timer. For the 500 grams, we were not in the spesified range of fifty-four to sixty-six seconds. We were under by a about three seconds for the full minute. As a result, we had to add weight and we then tested the weight in incriments of 10 grams. For the second variable that we changed, we utilized a smaller and tighter spring.


 * Specifications of Clock:**

Graph for the Variable Change of Weights



Graph for the Variable Change of a Spring



When a weight is heavier in mass, the amount of springs in a designated time will decrease. However, if a weight is lighter in mass, the amount of springs in a designated time will increase. The second variable is how much string is attached as a buffer between the spring and the metal frame. This piece of string may seem insignificant, but it actually serves as a shock absorber for the spring. By changing the length of the string, the results will probably differ slightly. The third variable is the width (size) of the coils, and in turn, this will have an impact on another variable known as the tension of the spring. If the coils are greater in width and have less tension as a result, the "bobs" of the weight will increase in time. Thus, if the coils are small and tight, the "bobs" of the weight will decrease in time. In addition to the size and the tension of the coils, the fourth variable includes the length of a spring. If a spring is long, the clock will become slower as opposed to a spring that is short in length. Finally, the fifth variable consists of where the spring and weight are released from or pulled down to. It does matter where the clock begins in that the process of "bobs" in a designated time can differ. This is because if one drops the weight and spring half way down, it will have a different result in time as opposed to pulling the spring all the way down to the table and letting it go. We did test this a few times and the results did differ.
 * Design Variables**: There are about five significant design variables that have the potential to cause the results to differ greatly. The first variable is weight.


 * Studied Design Variable 1:**

The first design variable that we manipulated was the mass of the weights that we placed upon the spring. We initially began with 700 grams and counted out thrity "bobs", fourty-five "bobs", and sixty "bobs" to obtain the amount time it takes for each of the three "bob" counts. We then increased our mass by ten grams until we got to 740 grams. Thus, we tested the mass of the weights five times with all three "bob" counts. We noticed that as we increased the weight on the spring, the "bobs" would increase in time and become slower. As a result, we also tested 500 grams released from the base of the table, and the time results were much quicker. We did not include this data in a chart but we reieved 16.75 seconds for twenty "bobs" amd 25.84 for thirty "bobs". In addition to support the five design variables described above, we also tested the fifth variable (weight and spring released from different places). For fun, we tested 500 grams released from the top of the metal frame (not exaclty the top but when the coils are not stretched out) and for thrity "bobs" we recieved a time of 24.63 seconds and for sixty "bobs" we recieved a time of 51.00 seconds. We were not extremely accruate in conducting this test due to the fact that we only have each thirty "bob" time count to compare. However, for the 50 grams released from the bottom and the 500 grams released from the top, there was a difference of 1.21 seconds. __See__: //Graph for the Variable Change of Weights// above for data and a chart to support the //Studied Design Variable 1//.


 * Studied Design Variable 2:**

The second factor we studied was a change in the spring used. The coils of this new spring were noticeably tighter than the coils of the initial spring. Also, the spring was shorter in length than the initial spring by about 1.25 inches. As a result, the time it took for the thirty "bobs", fourty-five "bobs", and sixty "bobs" to be completed was much less. The change of the spring was significant in that it was almost like losing ten grams of mass. For example, we were only able to test 730 grams and 740 grams due to a shortage in allowed time (otherwise we would have tested 4 different points for the change of the spring while keeping the mass a constant in comparison to the Studied Design Variable 1— as in testing 700 grams, 710 grams, 720 grams etc. like the first Studied Design Variable). But the 730 grams that we tested had similar results to the 720 grams of the initial spring and the 740 grams that was tested had similar results to the 730 grams of the initial spring. __See__: //Graph for the Variable Change of a Spring// above for data and a chart to support the //Studied Design Variable 2//.


 * Lab Questions:**

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 most accurately measure an event that lasts in 60s, one would use 740 grams for the total mass that is attached to the spring. There would be separate weights: one 500 grams, one 200 grams, and two that are 20 grams each. One must then pull the weights down to the base of the table in order to commence the experiment. Once the weights are released, one must let the spring bounce once and then start the timer as soon as the weights attached to the spring come back down to the surface of the table again. Then, sixty "bobs" should be counted out and one will recieve a time that is slightly over sixty seconds. __See__: //Graph for the Variable Change of Weights//.

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 mass was the most significant variable in effect of the frequency/period of the clock. If we built our clock with a 20% increase of weight from 740 grams, we would have a weight of 888 grams. This is because 20% of 740 is 148 (148 + 740 = 888). This would increase the frequecny/period by about 16.5 seconds per 60 oscilations. We did this by observing our data shown on our graphs. We averaged the seconds per 60 "bobs" for 700 grams, and 710 grams. Then we subtracted the average of 700 grams from 710 grams and got a difference. We repeated these steps until we had 4 differences between 700 grams and 740 grams. Now we averaged the differences to get an average of 1.1 second increase per 10 grams of weight. To solve the 20% increase, we multiplied 1.1 by 15 sets of 10 grams to get 16.5 seconds. By multiplying by 15, we accounted for 150 grams of added weight. We did round to 890 grams total to make this problem more simple. A more accurate answer might be an increase of 16 seconds per 60 oscilations.

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 least significant variable of our lab was the spring. The clock was consistantly less accurate with a different spring. We were not able to increase the spring variable by 20% so we cannot answer this question.

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 design would not be acurate for long time measurements. Over time, gravity would prevent the clock to "bob" at the same speed; making the clock less acurate. At 10-15 minutes the clock would most likely have stopped "bobbing". I don't know of a way to improve the design for a longer measurment. Gravity would still defeat our attemp to improve the clock.

We believe that our clock did produce a valid and reproducible result due to the collected data and our analysis of this data. We were able to test out system numerous times and with an increase of weight, the time would also increase appropriately and would be consistent for the most part with very slight alterations. The accepted value indicates accuracy and precision of the system. The experimental result of our data differs from an accepted value in that the accepted value would be accurate and therefore more likely to be reproducible with very consistent results. There is a great difference in something that is somewhat consistent and something that is very consistent. Thus, an accepted value would be better than the spring and weights that we used for the clock since they are not always reproducible. In order to make the spring and weight system reproducible every time, the “bobs” and the spring movement would have to be exactly the same each time. Our experiment could have been improved by taking more measurements of time in comparison to the “bobs”. We simply stopped at 60 “bobs” and should have gone past that closer to 90. In addition, there were times when we started counting the “bobs” right away rather than waiting for the weights to bounce back down towards the table once after letting go and then starting the timer. In addition, we were not always accurate when we stopped the timer so as a result, the times are most likely slightly off. Another factor would be where we were releasing the weights attached to the spring. We may not have been fully accurate in where we released the weights and spring from the table. We are aware that any alteration can meddle with how reproducible the results were and that human error in a lab like this is great.
 * Conclusion**


 * A statement about whether you think that the experiment produced a valid and reproducible result and reasoning supporting your statement.
 * A suggestion as to why your experimental results differ from any accepted value or your expected result (if appropriate).
 * A suggestion for a simple improvement to the experiment. Think about what caused problems, measurement inaccuracies, or inappropriate simplifying assumptions and propose a change. A sketch may be helpful.

>>>> >>>> //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?