4. Discussion

Part A
Key Findings
From the readings shown on the voltmeter connected to the set-up, we found out that the efficiency rate increased by 7% with cobalt catalyst added to nickel electrodes while the voltage decreased. This means that the cobalt did act as a catalyst, just like what we hypothesized before our experiment. What that essentially means is that the cobalt nitrate helped to increase the rate of the chemical reaction of water. Chemical reaction simply refers to electrolysis, because electrolysis is just using an electric current to drive a nonspontaneous reaction. We conducted the experiments three different times and averaged out the results read in the voltmeter and found out that the average drop in the reading after we added the cobalt nitrate is 0.28 Volts. This means that the process of electrolysis required a lot less energy compared to when we did not add the cobalt nitrate. This proves that cobalt nitrate improved the efficiency rate of electrolysis.

Evaluation of Key Findings
The efficiency rate increased when cobalt nitrate was added as the nitrate helped decrease the voltage.
This means that the cobalt nitrate helped to increase the efficiency of the process.
Cobalt Nitrate is used as a catalyst in the process of Electrolysis, which is the conversion of water to hydrogen and oxygen atoms. Before we added the Cobalt Nitrate into the beaker of Phosphate Buffer solution, the reading was at around 2.3V, meaning that the reaction requires 2.3V of electricity to split Hydrogen and Oxygen. After adding the cobalt nitrate, the reading slowly decreases. This is because the Cobalt Nitrate makes the process faster and more efficient.
Another experiment used catalysts formed from cobalt, oxygen and fluorine. They can be formed as a coating on an anode by conducting an electrolysis reaction using an electrolyte containing cobalt and fluoride. The catalysts will facilitate the conversion of water to hydrogen gas and oxygen gas, even at pH neutral/room temperature reaction conditions. (Gerken and Stahl, 2012)
This means that the catalysts will help to improve rate of conversion of water to hydrogen and oxygen gas, much like what we have gathered from our experiment.

Evaluation of Hypotheses
Our hypothesis is proven correct as the efficiency is improved when the cobalt is added.Because the rate of electrolysis is directly proportionate to the current of the Galvanostat, the rate of electrolysis is held constant. By adding the Cobalt Nitrate, we can see how much voltage is required to sustain that rate. When the catalyst is added, it makes the reaction easier to take place therefore the voltage drops. The reason for the increase in efficiency was that the cobalt-phosphate compound served as a catalyst which turned the nickel plated electrodes which were originally a bad catalyst for electrolysis. The catalyst dropped the required voltage to keep the same amount of current running through the circuit, thus making it more efficient.

Areas of Improvement
We could make improvements in method such as recording the exact amount of Cobalt Nitrate added each time to get more accurate results. The amount we put it which we call very little is a little vague and might affect the results of the experiment, even by a little. We should have instead used a set amount of Cobalt Nitrate each time to ensure that the experiment was as accurate as possible as compared to when we used just "a little" each time we added to the solution.

Because we did not collect the hydrogen and oxygen gasses collected onto the anode and cathode during the experiment, we missed our chance to collect the gases to compare prior to adding the catalyst and after adding the catalyst. Also, we could have used these gases to test out it’s effectiveness compared to other types of energy. By collecting the gases, not only do we have a more accurate way of comparing the results, we can also use it in other experiments.

Also, we should have recorded the efficiency over time. This helps compare changes over time and we can use a plot graph as data analysis instead of a vague calculated efficiency. With a plot graph, we can also measure the time taken for the cobalt to stabilise. We can replace the electrodes with another better metal conductor that is stronger in durability. The electrodes given is too flimsy, thus making it very hard for us to keep it intact.

Part B
Key Findings
There were many factors that affected the speed of the car as it passed through the photo gate sensor. Though the styrofoam figures did not affect the speed by a huge difference, it did affect the speed by a small amount, enough for us to find out the differences between the styrofoam pieces. we noticed that the airfoil figure (309.096cm/s) followed by the triangle figure (306.287cm/s) were the fastest and the slowest is the humvee shaped. (266.704cm/s)
This means that our hypothesis of the slimmest objects being the fastest is proven to be correct as it is shown in our findings. We hypothesized that the objects with lesser aerodynamic drag will have better airflow and thus have a better timing. This proved to be true, as shown in both our online research and our results.

Evaluation of Key Findings
According to our research we found out that the airfoil and general car shapes have a lower drag coefficient, the airfoil has a drag coefficient of 0.09 while the car has a drag coefficient of 0.16 compared to other figures that we have measured such as a block, which has a drag coefficient of 1.05. The results from our experiment relates to our findings. Because they have lower drag coefficients, it has reduced air resistance therefore having more more speed. (Tajos, 2002)
Because of drag, the car has to work harder to produce forces that push the car forward. As the car goes faster, the more it will be affected by drag. This is why non-streamlined vehicles such as a bus or a truck cannot go as fast as a racecar. That is because it can only increase so much if it is not aerodynamic in shape. The faster it goes, the more it will be affected by drag. This is why millions of dollars have been spent on research for developing racecars. To maximize the use of the engine and make the car able to reach higher speeds, the car has to be aerodynamic in shape, such as the airfoil and teardrop.

Evaluation of Hypotheses
Our hypothesis is correct as our fastest shape is airfoil and it is the most streamlined. This is because the airfoil has the lowest drag coefficient of them all the other figures we have measured and therefore our research on drag coefficient is proven correct because of the results found in our experiment. Due to the streamline shape, the airfoil does not cause as much drag as a bluff body would. Therefore the car travelled faster due to lesser drag acting on the car. By comparing the result of our experiment to a bluff body such as the block, we can see that the block, which has clearly more drag coefficient, has a slower speed compared to the airfoil. This is because there is more surface area exposed to the air thus increasing drag and reducing speed, unlike the airfoil.

Areas of Improvement
We could try to improve the accuracy of the experiment by ensuring that the weight of every single figure is the same. At our current point, the difference in weight of the styrofoam is negligible as the difference is only in milligrams, too small a difference to cause a major change in the results. However if we were to conduct our experiment on a large scale, it is advisable that we take note of the weight and if possible keep the weight of the figures constant. Another way to find out drag coefficient is by measuring acceleration as well. This is because drag has a direct effect on acceleration (HowStuffWorks, 2014). By measuring acceleration, this will give us a more well rounded result, in contrast to solely taking the speed of the car.

We should have requested a bigger styrofoam cutter as the one we had was too small to cut through a single block of styrofoam. We in turn had to use a hacksaw which was very troublesome as small styrofoam bits flew everywhere. By using a bigger styrofoam cutter, we can have a clean cut of the styrofoam block , not needing to polish it and thus saving more time for the more important part of the experiment.

Also, we could have done an experiment of hydrodynamics. As we all know, water is closer to solid than air and it would have been more challenging and interesting. Air is pretty basic as many people could have researched on that. We could have chosen a medium which is partially solid and water. Such examples would be detergent or gel. We could get a submarine model and attach different shapes to it. Another suggestion is to investigate aerodynamics in downward motion with gravity as a factor.

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