Which Alcohol is the best fuel?

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Emma Keller 11T         Which Alcohol is the best fuel?               Coursework

AIM: I am carrying out an investigation to see which alcohol is the best fuel. I will do this by experimenting with different alcohols and setting them alight and measuring different factors. I will analyse all my results and try to discover patterns, which should help me to conclude which alcohol is the best fuel.

PLAN

This is how my experiment will be set out:

Keeping this experiment a fair test

There are many variables in this experiment that can effect the outcome of this experiment. The dependant variables that I will keep the same will be the height of the tin can above the wick. I will keep this the same because different heights can effect the heat that is transferred to the tin can and into the water, therefore altering the temperature change. I will use the same tin can so that the experiment is fair and that different cans may be of different thicknesses so allowing different amounts of heat through. I will keep the amount of water that I put inside the tin can, the same for each experiment to be fair. I will decide on this amount from my preliminary experiment. The time for each experiment will also be kept the same to ensure the water has had equal amounts of time for it to heat up, again I will decide on the time from my preliminary experiment. The independent variables that I am measuring are the weight of the alcohol in the burner, both before and after the experiment, and also the temperature difference from before and after the experiments. I will also make sure that I take the lid off of the burner as late as possible, only when the burner it to be lit. This is because when the lid comes off a smell is released, so some gas is released which could alter my readings for the mass. This will also apply when replacing the lid after the experiment. I will make sure I keep this experiment fair by carefully controlling the variables.

My Preliminary Experiments

          Before I do my actual experiment I am going to carry out some preliminary experiments to help me decide on how much water I should use in the tin, the time I should allow for each experiment and the height above the flame. I will select the most appropriate and the one that gives the best results and best temperature change.

Table from preliminary experiment:

This tested a random alcohol

From these results I have decided to use 150ml of water and time for two minutes per experiment with a height of 5cm above the wick of the burner. I decided this because it gave a good temperature change and is suitable. Using 200ml of water did not give as good of a temperature change and it was quite a lot of water, which did not heat up as much. Also one minute was too short and did not give very good results. Three minutes was also too long for each experiment and the temperature change was large, making the water rather hot so, I decided to use two minutes as a suitable time to give me a good temperature change. Also at three minutes, the hot water could be dangerous and I want to ensure safety. I decided to use 5cm as a height above the wick because 11 and 8cm were quite high above the wick and the heat wasn’t really reaching the bottom of the tin can and was being transferred to the surroundings. Also 4cm was slightly too near so I chose 5cm as a reasonable distance.

         So from this I will be timing each experiment for two minutes with a 150ml of water in the can at a height of 5cm.

          I also performed another preliminary experiment, testing the use of blocks (bench mats surrounding the burner and tin can) to see if they kept some of the heat in and improved my results minimizing the amount of heat being let into the surroundings.

Table of results: A random alcohol tested for two minutes

         

From these results I have decided to use the blocks in each experiment. This is because it gave me better results as more heat went to the water in the tin can and not to the surroundings, giving me a better temperature change. To use the blocks I will place four bench mats around the burner and the tin can. I will remove one at the beginning so that I am able to light the burner and I will then replace it as the experiment is in progress. I will be careful when using the blocks as they could make my results inaccurate. To ensure fairness I will leave the three blocks in position around the burner and I will only remove the one block to light and extinguish the flame. This is so that the blocks protect each fuel in the same way.

Method:

  1. Set up the equipment as shown in the diagram below:

  1. Weigh the alcohol in the burner with the lid on and record as the ‘starting mass.’

  1. Fill the tin can with 150 ml of tap water using a measuring cylinder for accuracy. Then take the temperature of the water using a thermometer and record as ‘starting temperature.’

  1. Remove one block and take off the lid of the burner and light burner with a alight splint.

  1. Replace block and time the experiment for two minutes exactly using a stopwatch.

  1. As the experiment is in progress, stir the water in the tin can with the thermometer throughout the experiment. Be careful to ensure that the thermometer doesn’t touch the bottom or the sides of the can as this could change the results because the tin is a conductor and will be hotter in places.

  1. After the two minutes, extinguish flame, replace lid on burner and weigh again to record as the ‘ending mass.’

  1. Take the final temperature on the thermometer after it has stopped rising and record as the ‘ending temperature.’

  1. Calculate temperature change by subtracting the starting temperature away from the ending one. Also calculate the mass change of alcohol and burner by subtracting the ending mass from the starting one.

This method will help me to solve the problem because it is organised and systematic, enabling me to produce some accurate results of which I can record and eventually try to solve the original problem in finding out which alcohol is the best fuel.

Safety:

I will keep this experiment safe by using general common sense. I will be very careful when handling the alcohols so that I don’t get any in my hands, which could be dangerous especially when dealing with fire. I will also be very careful when lighting the burner and dealing with flames. Safety is an important issue and I will be careful to maintain safety in my experiment and follow general lab rules.

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The alcohols I will use:

I will use various alcohols to help me discover which out of these is the best fuel. I will experiment with:

Methanol                          CH  OH

Ethanol                             C  H  OH

Propanol                           C  H  OH

Butanol                             C  H  OH

Pentanol     ...

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