4.1 Key findings
Variable 1 -Heat
Variable 3-Flow rate
We found out that varying the heat had the most effect on the evaporation . We deduce this from the fact that when we increased the temperature, the rate of evaporation increases. The rate of condensation is increased as well because there is a greater amount of steam. There is a greater amount of heat energy heating the iron filament inside the heating mantle.The optimum temperature is 450 °C.
We found that varying the angle would be most effective in allowing the water to flow down to the condensation beaker due to gravitational force. The optimum angle was 50°. This is the angle which will simultaneously allow the water to flow down the surface of the condensing pipe and also allow the steam to condense on the aluminium strips.
We found that varying the amount of water did allow for more effective condensation on the metal plate but only marginally because, most of the steam was escaping. The greater the flow rate of water, the faster the pipes will be cooled down due to the cooler water passing through the pipes which will decrease the temperature of the copper pipes which are high in temperature.The optimum flow rate is #3.
Variable 1- 450 °C
Variable 2- 50 °
Variable 3- #3
4.2 Explanation of Key findings
The energy we used is 468 000 watts per experiment. This is regardless of temperature because the energy sent in to the heating mantle is always 260 Watts per second. So the amount of watts used for a 450 degrees is the same as on used for 50 degrees. Since total power= Watts X time, we used 260 watts X 1800 seconds= 468 000 Watts.
How much energy was used in one experiment- 468 000 watts
Explain how I got it
------------------------- = energy used to produce each ml of water (watts/ml)
So, our best efficiency rate was with the experiment that was at 450 degrees Celsius, 50 degrees angle and the third flow rate. Our efficiency rate was 19500 Watts/ml.
Our three key findings were; that increasing the heat had the most effect on the rate of evaporation, that varying the angle had the most effect on the water flowing down and that varying the flow rate had the most effect on the rate of condensation.
The first key finding can be proved by the fact that, there was a clear direct proportion between the two axes. For example, when the heat was increased, there was a clear increase in the amount of water evaporated
The second key finding can be proved by comparing the angle with the water collected. When we look at the graph, we can see that when the angle grows steeper, the amount of water collected also grows steeper. This was true for all experiments before 50 degrees. However, after a 50 degrees angle, we can notice that less water gets collected in the beaker.
The third key finding that varying the flow rate had the most effect on the rate of condensation can be proved by comparing the condensation rates between experiments where the other two variables were identical. That was how we saw that the faster the flow rate, the more the condensation
4.3 Evaluation of Hypothesis
- Hypothesis 1: A 40º-50º angle will be the optimum range of angles that will affect the condensation of the water vapour and allow for the most efficient water collection
This hypothesis proved to be correct because the water was able to flow down by itself due to gravitational force. The water droplets were heavy enough to flow down by themselves.In the V-shaped metal strip, the water droplets will join in order to flow down to the collection beaker .
- Hypothesis 2: We predict that the higher the flow rate of water through the hollow copper pipes, the faster the rate of condensation, resulting in a greater amount of water.
Our hypothesis was correct again. This is because the temperature of tapwater is lower than the temperature of the steam that is evaporating from the round-bottom flask. The temperature of tap water is 7-12 °C. When steam evaporates , it loses heat to the copper pipes .The copper pipes will gain heat. If the temperature of the copper pipes is too hot, steam will not have a cool surface to condense on. The water flowing through the pipes is to keep the copper pipes cool to allow steam to be condensing on its cool surface continuously. Thus, the greater the flow rate of the water, the faster the heat transfer between the copper pipes and the water flowing through it.
- Hypothesis 3: We predict that the greater the amount of heat used to boil the water, the faster the rate of evaporation, which will result in a faster amount of time for the water to be collected in the beaker.
Our hypothesis was proved to be correct again as there was a greater amount of heat applied to the iron filament, the faster the speed that the water is being heated up .As a results, a greater amount of water evaporates and condenses in that 30 minutes of time. As a result, a greater amount of water produced for the experiment.
Previous researches have shown that the more heat applied, the higher the rate of evaporation, but there haven’t been researches that clearly define the optimum angle for water to flow down and neither has it been proved that the flow rate has a direct correlation to the condensation rate. So, our research was mainly focused on solving our hypotheses.
AREAS FOR IMPROVEMENT
Instruments -If we were provided with better instruments, then we could have performed our research on a larger scale. The results would have been more obvious and could clearly hae been observed. If we were given access to better instruments, we would have created more efficient ways to conduct our experiment like use copper pipes that are directly connected to the tap instead of using rubber tubings to connect the copper pipes to the tap.
Scope of Research- The scope of research would have definitely have increased as the budget assigned to the research would have definitely increased. The scope of research would be larger as there would be a greater amount of time and resources at our disposal. A greater scope of research would result in better results.
Instead of using the stopwatch to get the results, if we used an instrument with a higher degree of accuracy, the method of obtaining results could be improved and the results obtained will certainly be more accurate than before.
We can use different types of graphs to analyse the results in a better way. We can also use pie charts to compare effectively.
The heating despite being heated well, we noticed that some of the steam was condensing inside the round-bottom flask itself. To counter this problem, we could have gotten a similar round-bottom flask with a much larger spout.
To make the change in angle more noticeable, we could have had more smooth and broader aluminium plates so that the water would slide down more easily. Another problem we noticed was that most of the steam was escaping so we could have enclosed the entire setup or had a sheet of aluminium at the side to prevent the steam from escaping. This would have allowed the angle change to be more noticeable with the higher condensation rates.
The change in the flow rate was not as obvious as we expected it with only marginal differences between the amount of condensation. We can link this to the fact that most of the steam was escaping so we could have enclosed the entire setup or had a sheet of aluminium at the side to prevent the steam from escaping. This would have allowed the change in the flow rate of water in the pipes to be more noticeable with the higher condensation rates. We also faced a lot of difficulty in testing out the higher pressure flow rates as the pipes we had kept falling out or bursting due to the water pressure being too high for it to take. What we could have done was secure it better so that the pipes wouldn't fall out.
Our rubber tubing wasn't very well set up. We faced difficulties while conducting experiments with flow rates, 2 and 3. This was because the rubber pipe that was connecting to the tap wasn't secured and we couldn't get it to stay there without someone attending to it at all times.
Our plates were rather well setup but, some of the plates still had dents on them and weren't connected well. For example, two of the condensation plates had gaps in between them and, some water droplets went there instead flowing down the beaker. If we had the plates smoother, the water flow would be much better and if there were no gaps, we would probably have seen a difference in the results ranging from 2-3 ml
Our pipes were well set up for the most part with some pipes being bent far too much while the copper pipes were bent perfectly for the most part. We could have bent the aluminium pipes more carefully by stopping every 10 degrees of bending to make sure that it does not break due to metal fatigue.
With more aluminum plates, we could have directed the steam to the condensation plate much better and then, we would have gotten more conclusive results. For example, if the steam was better directed to the condensation plate then, more water would have condensed and flowed into the water. With better resources, we could have increased our scope of research by adding more variables such as if the material of the copper pipes actually affected the rate of condensation or if the material of the metal plate did.
We could have conducted this experiment in an enclosed set up such in an enclosed distillation column or we could have added more metal plates to direct the steam to the intended condensation plate. This would have allowed us to get more condensed water since most of the evaporated water escaped into the atmosphere instead of condensing. If we had thought of this before starting the experiment, we would have gotten much better and more conducive results.
Conducting the experiment
Our experiment had minimal results only because, most of the evaporated water escaped into the atmosphere rather than condensing on the condensation plate. If it was better done, we could have noticed the differences in flow rate and angle much more.
We were not always on task while doing the experiment and sometimes, we would accidentally knock over the entire retort stands and copper pipes once which caused us to spill water all over the floor and, restart the experiment. We also pulled out rubber tubing twice and had to repeat the experiment. We also played around with the water occasionally instead of being focused on conducting the experiment.