- Independent: Mass of the weights (Newtons).
- Dependent: Extension of the spring (centimeters).
- Controlled: The same type of spring (the size and strength of extension) is used for every trial, so the difference between each weights can be observed more efficiently.The number of weights added onto the spring for each trial.
====================Figure 1: The set up of the spring experiment.
- The following materials were used during the experiment; a meter stick, a spring, (that stand thing), weights (0.5N, 1.0N, 1.5N, 2.0N, 2.5N and 3.0N), and one mystery object.
- We set the spring onto the stand and recorded the starting position of the spring before a weight is attached.
- After attaching a weight onto the end of the spring, we measured the extension of the weight when the mass was added. The extension measurement is the length it had stretched subtracted by the height of the spring’s starting position. We repeated this process for the 0.5N, 1.0N, 1.5N, 2.0N, 2.5N and 3.0N weights.
- The data was recorded onto the excel worksheet. And we have done a total of 3 trials.
- Using the data we have collected using the six weights, we estimated the weight of the mystery object. In our case, the string extended a little over 22cm so we estimated that it weighed 2.25N, which was only 0.02N away from the true weight of the object.
- With the data from the extension of the string when mass is added, we have calculated the mean, range and 1/2 range to make our graph. The calculations of the mystery object was added into the graph as well.
==Figure 2: The extension of the spring when a certain weight is added.
- Every half Newton we add onto the spring, the spring extended 5cm.
- As the mass placed on the spring increase, the spring extended more.
- By looking at the graph, we can tell that the extension is close to the weight of the mass.
- Add a zero behind the weight mass number, to get the extension measurement.
=====================Figure 3: Measurement of the force when
==========================the weight is added onto the spring.
- By looking at the graph, the extension of the spring gets greater as the weight attached increases.
- The reliability and validity of the graph is very high because the error bars are very small and the range of the data collected were very small.
- The trend of the data can be seen as every 0.5N you move from the x-axis of the graph, the extension length increases by 5cm. So when 0.5N has been added onto the spring, the extension length increased by close to 5cm and when 1N weight was added, the spring extended 10cm.
- The relationship can be seen between the weight’s mass that has been added onto the end of the spring and the total length the spring has extended. The more force applied onto the end of spring, the more the spring stretches in a greater extent.
- We were assigned mystery object #1 and the extension of the spring was a little over 22.5cm. Our estimated weight of the mystery object was 2.25cm. This was process with all the observations we have made of how for every 0.5N, the spring extends 5cm and you could multiply the Newton number by 10. The ‘true’ weight was 2.27 and so we were only 0.02cm away from the correct value.
- The % error was found by using the % error form:
- % Error Form = (measured – ‘true’/ ‘true’) x 100
- ************* = (2.25 – 2.27/2.27) x 100
- ************* = – 0.88%
- Because of our very low % of error, we can tell that our data is very reliable.
- As for our research question, “Can we use a spring to accurately measure force?” the answer would be yes if the validity and reliability of the data collected is high. Since the spring is stretched further away from its original position when the weight is added, the force of the mass can be measured by calculating the difference of length from the original position to the position when extended. Also, because of the spring force, we can tell that the weights will not reach to the ground because the force is holding the object up. According to Henderson (n.d.), the English scientist, Robert Hooke, was the first to discover the relationship between the force applied to a spring and the amount of extension in 1678. As Hooke put it: Ut tensio, sic vis which means “As the extension, so the force.” That is to say, the amount that the spring extends is equivalent to the amount of force with which it pulls (Henderson, n.d.).
- For future related investigations, I think measuring tapes would be a more precise material to use instead of the wooden meter stick. It would allow us to measure the extension of the spring more accurately and would allow less error in our data, causing it to stay very reliable. Also, it would be easier to work in the lab room with the higher desks because the stand can be moved to the very edge of the table, unlike the small curvy-sided desks, and measure the extension of the spring more easily and precisely.
Self-Assessment (Criterion E)
I think I deserve a 5-6 level because the majority of the level descriptors that had fit my work was in the 5-6 range. I have collected sufficient data from all 3 trials and recorded it into a neat data table. The trend, pattern/relationship and reliability of the data was commented on, in the graph section. The data was presented very neatly and all the calculations of error bars, mean, range, 1/2 range, % error form have been made to make an overall graph that suits this investigation. I have drawn a conclusion using scientific reasoning and have interpreted the data for the mystery object and how the calculation of the % error form was made. The conclusion may not have been clear, but the interpretations of the data were correct. Also, visuals of how the experiment was set up was included.