# See how one factor affects the period of time a mass on the end of a spring takes to complete one whole oscillation.

Michael Deacon

Physics Coursework

Planning

## Variables

The aim of these experiments will be to see how one factor affects the period of time a mass on the end of a spring takes to complete one whole oscillation.  One whole oscillation means the mass returning to its original position, be it the equilibrium or not.

I will look at the independent variables (variables which are not caused as a result of another variable).  The dependent variable in this case is time

• Mass – the size of mass on the end of the spring.  Bigger mass may affect the time it takes
• Length of spring – if the spring is longer, the mass would have further to travel and this will affect the time it takes to oscillate.
• Tension of spring – the more tension in the spring may result in the mass oscillating faster as there would be more tension.  This would prevent the mass pulling the spring too far and thus mean the oscillating time would be shorter.
• Gravity – the force of gravity would affect the mass, as if the gravity was less the mass would take longer to pull the spring down.  If the gravity were stronger, the mass would take longer to go back to the equilibrium.
• Temperature – if the temperature changed, the spring would be more ductile and this could mean the spring would deform earlier than it would at room temperature.

I have chosen to make mass the variable, as this is the easiest variable to use in this experiment.

## Equipment

Here is a diagram of the equipment I will use:

## Method

This is how I will carry out the experiments:

1. Set up the equipment as shown in the diagram
2. Put the mass on the end of the spring (see below for range)
3. Measure the initial displacement (see below)
4. Time 10 oscillations, and divide this answer by 10.  The reason I will time 10 and divide by 10 is that it is far more accurate than trying to measure one.
5. Record the results
6. Do each experiment three times to produce more reliable results when an average is taken.

The range, which was decided in the preliminary ...

#### Here's what a star student thought of this essay

Their quality of written communication is very good, and the report is presented well, in a logical order, with suitable sub-headings, tables, and a formal tone. The use of bullet point is also good as it makes the report much easier to read and be marked. There are no noticeable grammatical or spelling errors. Occasionally they have said things such as "I have chosen to make mass the variable, as this is the easiest variable to use in this experiment." This is not I good idea as it suggests they are being lazy - it is much better not to mention why they chose this - the examiner will just assume you could only pick one variable and just happened to pick mass - you don't need a good excuse! They could also gone into a little more depth in some sections, for example giving suggestions for better measuring equipment they would have preferred to use. Despite these small errors, the report reads well and their quality of written communication is very good.

The candidate has used the results of the experiment to calculate the average speed and kinetic energy of the oscillating mass. They have also analysed the results to identify an outlier, and discussed a potential cause for the outlying value. They used the results of their preliminary experiment well, in order to chose the best range to test the spring over without exceeding its elastic limit. However, it may have been better to instead find the limit of proportionality in order to only test the springs while they obeyed Hooke's Law, as this will have affected their results. Despite this, they have still managed to pick a suitable range of masses, and justified their decision well. When planning the experiment, they have shown evidence of attempting to reduce the uncertainties, although it would have been better to use the heading 'reducing uncertainties' rather than 'fair testing'. Also, within this section, they decided to use different springs for each experiment. It is usually best to use the same spring as each spring will have a slightly different stiffness, and is unlikely to be affected by previous use unless stretched beyond its elastic limit (which was found in the preliminary experiment). The candidate has shown evidence of strong logical reasoning and scientific understanding, particularly in their detailed explanation of their hypothesis - in which they described Newton's second Law and how it can be used to predict that the acceleration would decrease as the mass increases. They then carried out the experiment to demonstrate this relationship.

The candidate has carried out a well-planned experiment to measure how changing the mass of a spring oscillator affects the time of oscillation. They have produced a well-presented written report. However, they have failed to have explicitly answered the question in the form of a clearly-stated conclusion, and instead gone off topic by discussing the kinetic energy of the oscillating mass, which has very little relevance to the original question.

Their quality of written communication is very good, and the report is presented well, in a logical order, with suitable sub-headings, tables, and a formal tone. The use of bullet point is also good as it makes the report much easier to read and be marked. There are no noticeable grammatical or spelling errors. Occasionally they have said things such as "I have chosen to make mass the variable, as this is the easiest variable to use in this experiment." This is not I good idea as it suggests they are being lazy - it is much better not to mention why they chose this - the examiner will just assume you could only pick one variable and just happened to pick mass - you don't need a good excuse! They could also gone into a little more depth in some sections, for example giving suggestions for better measuring equipment they would have preferred to use. Despite these small errors, the report reads well and their quality of written communication is very good.

The candidate has used the results of the experiment to calculate the average speed and kinetic energy of the oscillating mass. They have also analysed the results to identify an outlier, and discussed a potential cause for the outlying value. They used the results of their preliminary experiment well, in order to chose the best range to test the spring over without exceeding its elastic limit. However, it may have been better to instead find the limit of proportionality in order to only test the springs while they obeyed Hooke's Law, as this will have affected their results. Despite this, they have still managed to pick a suitable range of masses, and justified their decision well. When planning the experiment, they have shown evidence of attempting to reduce the uncertainties, although it would have been better to use the heading 'reducing uncertainties' rather than 'fair testing'. Also, within this section, they decided to use different springs for each experiment. It is usually best to use the same spring as each spring will have a slightly different stiffness, and is unlikely to be affected by previous use unless stretched beyond its elastic limit (which was found in the preliminary experiment). The candidate has shown evidence of strong logical reasoning and scientific understanding, particularly in their detailed explanation of their hypothesis - in which they described Newton's second Law and how it can be used to predict that the acceleration would decrease as the mass increases. They then carried out the experiment to demonstrate this relationship.

The candidate has carried out a well-planned experiment to measure how changing the mass of a spring oscillator affects the time of oscillation. They have produced a well-presented written report. However, they have failed to have explicitly answered the question in the form of a clearly-stated conclusion, and instead gone off topic by discussing the kinetic energy of the oscillating mass, which has very little relevance to the original question.