Dependant factors include the amount of oil I will use.
I will control the factors by keeping everything accurate, I will use the same equipment every time so the slightest imperfection in a tile does not affect my experiment, I will use oil from the same source so I am confident that my oil is the same, I will keep the angle of the tile accurate by measuring it with a protractor
Equipment
I have chosen equipment based on my previous knowledge of carrying out experiments and the background information I collected
- Ceramic tile – the edges are even and are easy to wipe making the test fairer, than if I used a plank of wood for example
- Wooden block – to prop up the tile at a constant angle, I have chosen this as it will not slip and will keep the test fair
- A electronic timer – I have chosen to use a timer as they give far better results and are far more accurate than using a mechanical wall clock and it also enables me to keep all eyes on the experiment and record multiple experiments at once
- Oil – I will be using 5 different oils to widen my results
- Syringe – I will use a syringe to make my test fairer and more accurate, using a syringe is more accurate than pouting the liquid out of a bottle
I know how to use all of this equipment safely and accurately
Prediction
Because of my previous investigations on oil and my scientific knowledge that I gathered from my research I predict that the more hydrocarbons that oil has the longer it will take to get down a tile.
My reason for this comes from oils uses, thick oil is good for high temperature fuels and thinner oils work best at low temperature
For instance diesel is quite thick, and requires a high temperature to burn, making it more suited to Lorries and busses where as it wouldn’t be very good in a plane at low temperatures, that’s why they use kerosene in planes, as it burns easier making it safer to use.
Results
I have chosen to take 3 results for each experiment; this will give me a far better understanding of my experiment and will enable me to add them together and divide by 3 giving me an average which will make my line graph more accurate
I will measure the time it takes each oil to travel down a tile in seconds and this will be done using an electronic timer that goes to two decimal places.
Safety
I will make sure everything is accurate; an accurate experiment is nearly always safer, as you are aware of what is happening always.
I will use gloves, as the oils won’t do any good to my skin if I do get any on it
I will also use goggles as it won’t do my eyes any good either
I will also make sure all my oils are disposed of in a safe way
Preliminary Trials
I carried out some preliminary trials to give me a better understanding of my experiment and I will make decisions for my method based on this
I have decided that 20˚ was not steep enough, it took far too long for the thicker oils to move and it wouldn’t give me a wide set of results, so I experimented with some other angles, still using the thickest oil hexadecane and hexane, saving me time yet still giving me just as good of an idea of the range.
At 60˚ we found that it was too steep for the thinner oils and would not give far results so we carried out some more experiments at 20, 30, 40, 50 and 60 degrees and decided that 35˚ would also give us the best range of results.
Method
I will set up my equipment and make sure it is on a flat solid surface to prevent any interferences, I will then measure the angle of the tile and make sure it is 35˚ exactly with a protractor, I will then collect my oils and return, the oils will be kept with lids on so I don’t spill anything and I will then draw the lines on the tile 1 cm parallel from each edge so it works like a race.
I will then again measure the angle and set up the timer
After this I will get my first oil and get the correct amount (0.02 ml) and put that amount on the tile, accurately and evenly every time, I will then start the clock and wait for the oil to run to the bottom line a few centimetres down.
I will then take results on a table and then repeat 3 times before moving onto the next oil.
I will wipe the tile each time and make sure its dry again to make the test fair.
Order
I will take all the results in an orderly fashion and repeat all results 3 times to get averages
I will also work in order of hydrocarbons for neatness sake.
Results
I obtained accurate results by carrying out an accurate experiment and monitoring everything that was going on all the time
It is clear from my results that the more hydrocarbons a oil has the more viscose it is and the longer it takes to travel down a tile at 35 degrees, my results were precise as I kept my equipment clean and always fair I also used the most accurate equipment available to me (ceramic tiles were adequate for my results but it would be better to use something more accurate like a pressure pad)
I think someone could quite easily repeat my method and get similar results as I have given detail on every aspect of my investigation when it comes to equipment, the procedure and everything has been thought, off.
I think my results are reliable, I couldn’t have made my test any fairer with the equipment available to me and I also couldn’t have made my tests any more accurate with the equipment available.
There is more of a consistency between the results with the thinner oils than the thicker oils, I can only note this down as an anomaly as of human error.
Analyse
Conclusion
To sum it up I have found from my experiment and investigations that the more hydrocarbons a particular oil has the thicker it is and in this case longer it will take to run down a ceramic tile.
From the graph and bar chart I can see that that the number of hydrocarbons affects the viscosity, I believe this is happening because of the friction between the hydrocarbons and the particle alignment.
I have seen this happen before when I previously investigated the properties of ice water and air.
Particles in ice are very tight and compact, they are so tight and aligned that they barely move.
In water they are looser and that’s why water takes a liquid form.
And in gasses the particles are much farther apart.
Well this is just on a slightly more complex scale, the hydrocarbons are links and they get interwoven like wool and it works on a similar principle.
This is why the more hydrocarbons in each link in oil the thicker and longer it takes to run down a tile it is.
*-see the top of page 3 for this information
Bar Chart
My bar chart has been included on graph paper in the sleeve.
Correlation
There is a distinct positive correlation in the results as you can see on the bar chart and line graph, as the number of hydrocarbons goes up so does the time it takes to get down the tile.
Line Graph
I have included the line graph in the plastic sleeve
Prediction
I have proved my prediction correct and have found that there is a distinct correlation between the different results, I think my results do match up to my prediction however there is a steep increase after octane and this considerably surprised me, I thought that there would be a more even increase as the number of hydrocarbons goes up.
Evaluation
Evaluation
I carried out my experiment in the best possible way; my results were very fair and accurate
My results were as accurate they could have been with the resources available.
My method was of a good standard, I kept to it without making it too lenient or too strict.
My method allowed me to have the freedom to carry out the experiment in a safe way but still managed to keep it strict enough so I didn’t go off task or make the test unsafe or inaccurate.
I think I could make my experiment more accurate by using more precise equipment, like a more accurate clock.
I think my results are highly accurate which makes them reliable.
I think I went wrong when I investigated the time it took to get down the tile; I could make my experiment better by getting the speed that they travelled at.
My graph shows that I worked well with a good range and work in the best way possible.
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