# The problem with pendulums

What follows is a detailed analysis of problems in a student's write-up of a Physics practical. The analysis focuses only on the 'Evaluation' section, since this was where the student's weaknesses of language were most apparent.

The script overall was really pretty competent - at least, to my Physics-ignorant eye. There was a sound, methodical overall plan, with headings (see Practicals writing frame , where the student's plan appears as example A.) Simple declarative sentences were used to describe the experimental procedure and the handling of data. Mathematical logic and tables appeared to be used efficiently, and supported appropriately by, again, simple declarative grammar.

The concluding sections on 'Evaluation' and 'Improvements' necessarily demanded more complex language. She had to criticise the experimental method, explaining cause and effect, discussing possibility and probability, and suggesting improvements (italics indicate language functions). It is apparent that she lacks, or misuses, certain sophisticated language elements within the Transferable Academic Language (TAL) range, and needs more resources of precise technical vocabulary. That said, she has quite a sound command of many aspects of complex language ... she is on the verge of developing real dominance of sophisticated expression.

Here is the original text of the 'Evaluation' section. Phrases highlighted in blue have hover titles, commenting in detail.

### Analysis by language

Evaluation

Based in the results obtained the value obtained for the gravity is 9.63 m / s2 ± 0.7 witch show us that there was a good process because the value obtained is really close to the actual value used in the books and other references. Although the uncertainty has a big value witch is product of different factors, especially in the used equipment.

The facts that affect the uncertainty were that the stopwatch used was not very precise because it only measure the time in seconds and in this case will better use a stopwatch with decisecond, This is an very important fact because to find the gravity you are looking for a very precise date and one second to each other is too much difference.

Besides the problem of time did not only affect the uncertainty it also affected the final results because this is the basic value for get the time period witch is part of the formula for get the gravity .

Looking back in the process, the construction of the pendulum had some problems because the mass suspended by the rope did not fall exactly to the center. This was because the knot made, gave a variation in the position of the mass therefore there was an inclination.

Furthermore during the process, I took different lengths and times, so the angle taken to release the pendulum was a small angle in all the cases but even though I tried to use the same angle all the time, it was impossible to be precise if you do not use something to measure the angle. Thus this affect the result since the number of oscillation can change according the angle. Although In this practice does not necessary take the angle because the formula do not ask for that it could be better use a exactly precise angle for all the dates.

Other small problem that could affect the final result was that the pendulum was held by a rule that was in the table held by my hand, therefore the rule could move so the pendulum had been affected.

The value obtained for the gravity is less than the normal due all the fact analyzed before: The problem with the time, the wrong position of the mass, the imprecise angle used for each case and finally the external fact upon the pendulum like the rule held by my hand.

However I think that in general this practice got very good results because I found what I was looking for, also because it was what I was expected.

### Analysis by structure

Her specific language problems aside, the student has a sound approach to structure. There are 8 paragraphs, and each paragraph has a clear topic contributing methodically to a developing argument. Consider the following analytical summary :-

Para 1  ... Introduction: sound experiment, but problems with 'uncertainty'

Para 2  ... uncertainty-related problem - measurement imprecise

Para 3  ... imprecision affects final results

Para 4  ... problem with construction of pendulum - the knot

Para 5  ... problem of lacking "exactly precise angle" (slightly confused, not fully thought out?)

Para 6  ... the wobbly ruler affecting precision

Para 7  ... summary of flaws which affected results

Para 8  ... 'conclusion' - 'pretty good, considering'

Para 7 is particularly clear and effective in terms of succinct explanation. Indeed, it could have been moved to the beginning, to introduce her detailed points - which could then have been emphasised / clarified through the use of bullet points. She would have had to re-phrase a bit, but this is what it might have looked like :-

Based in the results obtained the value obtained for the gravity is 9.63 m / s2 ± 0.7 witch show us that there was a good process because the value obtained is really close to the actual value used in the books and other references. Although the uncertainty has a big value witch is product of different factors, especially in the used equipment.

The value obtained for the gravity is less than the normal due to (delete: all the fact analyzed before): The problem with the time, the wrong position of the mass, the imprecise angle used for each case and finally the external fact upon the pendulum like the rule held by my hand.

• The facts that affect the uncertainty were that the stopwatch used was not very precise because it only measure the time in seconds and in this case will better use a stopwatch with decisecond, This is an very important fact because to find the gravity you are looking for a very precise date and one second to each other is too much difference.

• Besides the problem of time did not only affect the uncertainty it also affected the final results because this is the basic value for get the time period witch is part of the formula for get the gravity .

• Looking back in the process, the construction of the pendulum had some problems because the mass suspended by the rope did not fall exactly to the center. This was because the knot made, gave a variation in the position of the mass therefore there was an inclination.

• Furthermore during the process, I took different lengths and times, so the angle taken to release the pendulum was a small angle in all the cases but even though I tried to use the same angle all the time, it was impossible to be precise if you do not use something to measure the angle. Thus this affect the result since the number of oscillation can change according the angle. Although In this practice does not necessary take the angle because the formula do not ask for that it could be better use a exactly precise angle for all the dates.

• Other small problem that could affect the final result was that the pendulum was held by a rule that was in the table held by my hand, therefore the rule could move so the pendulum had been affected.

However I think that in general this practice got very good results because I found what I was looking for, also because it was what I was expected.

### Support for the student

It would seem that here we have a capable student who is not displaying her sound grasp of Physics effectively enough due to flaws in language. How can she be helped?

She needs to

• revise and clarify her (sometimes competent) use of sophisticated linking structures (part of TAL) - ... although ... due to ... in order to ...
• learn to use, appropriately, the Third Conditional   (e.g. "If I had ..., it would have ..." )
• acquire more technical vocabulary, in order to distinguish correctly between a wider range of options - e.g. experiment = ... procedure ... process ... method ... technique ... approach ... ??
• consider, perhaps, a wider range of structural possibilities - for instance, the use of bullet points, insetting paragraphs, etc

So who does this? How? When?

The practical way to resolve those questions is for the school to have a policy on English as the Language of Instruction, with a clear division of responsibilities.

#### Use for teaching

The text of the student's Evaluation is available as a handout

This text can be given out to students to explore the aspects indicated in my notes above :-

Correcting Language  ...  Pose the following questions to the class ...

? Does language make the meaning unclear at times? If so where, exactly?

? Which bits of the language really need correcting?

? How would you re-write the unclear sections?

Summarising the text ... Ask the students to summarise what each paragraph is about - then discuss whether the structure / paragraphing is clear.

Re-ordering the text  ... Using the letters identifying each paragraph, ask the students to list the letters in a different order. Aim to elicit my suggested re-ordering above, perhaps?

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