Experiment to investigate the relationship between speed and depth for a water wave.

Physics Coursework

Aim: Experiment to investigate the relationship between speed and depth for a water wave.

I predict that the greater the depth of water the faster a water wave would travel.

Speed=distance travelled / time

Prediction:

As I explained earlier, the greater the depth of water the faster a water wave would travel. The angle of the guttering is a major factor in this as changing the angle would make the guttering unlevel and will slow down the wave therefore making the experiment unfair.

Apparatus:

The equipment I need to carry out the work and to obtain my results is:
· A length of gutter
· Water
· 250cm3 Beaker
· Metre Ruler
· 30cm ruler
· Retort stand
· Clamp
· String
· A wooden block
· Stopwatch

Diagram:

Preliminary Work:

Preliminary work is the work that is done beforehand for you to know that the experiment is going to work. It is a way for the person carrying out the experiment to know that it has been set up correctly when the actual experiment begins.
For my preliminary work, I did the experiment and tested that a wave would be able to be created. The preliminary work brought up the problem of how high the wooden block should be held up before it is swung into the water, it was decided that it should be swung from about 4cm above the bottom of the guttering.
Safety Precautions:

Even though safety is a virtue the experiment being conducted is a relatively safe one. The only major danger is slipping on the water, which has been spilled, and so when water is spilled the water is cleaned up immediately.

Method:

Firstly, I measured the deepness of the water, which started at 2cm deep and progressed up with 0.5cm intervals until the experiment was 4.5cm deep. To start off the wave the wooden block was raised to 4cm from the bottom of the guttering and left to swing down freely to start the wave. As soon as the wooden block has been dropped the timer was started and measured the time for the wave to be refracted off the far side of the gutter and back to the point where the wooden block struck the water. I repeated each temperature ...

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Observation

When I conducted the experiment it proved my prediction right. The greater the water depth the faster the wave would be. I noticed that the wave started out quite strong and gradually shallowed out as it reached the end of its passage.

Results:

Averages:

2cm =25.05 / 3 = 8.35 sec

2.5cm = 21.06 / 3 = 7.02sec

3cm = 19.65 / 3 = 6.55sec

3.5cm = 19.39 / 3 = 6.46sec

4cm = 18.37 / 3 = 6.12sec

4.5cm = 17.1 / 3 = 5.7sec

Conclusion

From my results, I have come to the conclusion that if the depth of water is increased the faster the wave. The wave speed increased as the depth increased and so I think it was due to the larger area for the wave to move the faster the wave would move.
At the lower depths, the time taken for the wave to move was slower because of friction which slows the wave down.

Evaluation

I think that this experiment has gone very well for me. My results were of a particularly accurate standard as I tested each depth three times and I calculated an average from these times. There were no strange results (anomalies) within my results table and I think that this was because of the extreme caution and care that I put into making sure that the experiment was set up correctly with careful measuring of water and time.
I think that I could have repeated my results more however for the reason that I feel although the experiment was repeated three times, the most accurate results in experiment can only come from constant repeatability which I did not display in my experiment. That said, the time allocated did not allow me to do so and I believe as an improvement of what I could do if I did the experiment again, I would have to say that, with more time, I would repeat the results further for even more accurate and reliable results.
I believe that I could have improved the method by making it more specific. I stated clearly all the various methods I took in setting the experiment up but I could have been more specific to how all the apparatus was used and perhaps why I used the apparatus I did as well.
I believe that I did get a suitable range of results for this experiment.
Some other areas in the experiment that I feel I could have improved on were factors like controlling the stopwatch and measuring the depth of water. There is lots of room for human error here. However the inaccuracies due to them were negligible because I paid close attention to these during the experiment.
Overall, this investigation has been a very successful one. I feel my results and analysis have been as accurate and reliable as they could have been under the time allocated. However I feel with extra time, I could have repeated the experiment and made it even more accurate and adapted it to try other variables i.e. adding a small obstruction or using water with salt dissolved in it. These are the ways that I could expand on the original question.

Andrew Chadwick Page

Peer Reviews

Here's what a star student thought of this essay

skatealexia

26th of Aug 2012

Quality of writing

Punctuation, grammar and spelling all done to a good level. Tone and format of the experiment also done well.

Level of analysis

The candidate makes a prediction, but they do not really say the reasoning behind the prediction which should be explained to show an understanding behind what they are predicting. They do consider certain factors which may affect the experiment which will make the experiment more reliable in the long run. The diagram provided is good because it allows future people to be able to accurately conduct the experiment again. The candidate shows evidence of carrying out preliminary work which is good because it shows that the candidate considers factors beforehand which may affect the experiment by trialing the experiment. This will make the results more accurate. The method is explained well. They attempt to explain the theory behind the wave in the conclusion but this is only done to a basic level. The analysis is good and outlines a variety of improvements to the experiment.

Response to question

A well done experiment. This is achieved by the candidate carrying out a preliminary experiment and explaining the method well, alongside a good evaluation. The experiment lacks scientific depth behind the reasoning which is the main thing that should be improved.

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