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### 4. Discussion

4.1 Analysis of results

TestControlLight (decrease)Surface Area (decrease)Temperature of hotplate (decrease)Wind (increase)Purity (decrease)
135331823339
234231523542
329271653637
Average amount of water evaporated32.727.716334.739
Rate of evaporation per min3.272.771.60.33.473.9
Difference from control0.51.672.970.20.63
Results are the amount of water evaporated.
Average amount of water evaporatedRate of evaporation per minDifference from controlIn ascending order of difference
Purity(decrease)39.0(3SF)3.9ml0.63Temperature of hotplate
Wind(Increase)34.7(3SF)3.47ml0.2Surface area
Control32.7(3SF)3.27ml-Purity
Light(decrease)27.7(3SF)2.77ml0.5Light
Surface Area(decrease)16.0(3SF)1.6ml1.67Wind
Temperature of hotplate(decrease)30.3ml2.97

We found out that the temperature of water affected the rate of evaporation the most, followed by surface area, purity, light and wind. As expected, the independent variable affects the rate of evaporation increases or decreases according to the different independent variable but does not remain the same as the control

4.2 Explanation of key findings
Our key findings are that:
Temperature of hotplate affects the rate of evaporation the most.
Wind affects the rate of evaporation the least.

An explanation for this is that heat energy moves directly to the water molecules which enables them to overcomes the forces of attraction while wind would decrease the humidity above the surface of the water and increase the surface area of the water which is changing the surroundings of the water so as to increase the rate of evaporation indirectly.

4.3 Evaluation of Hypothesis

The hypothesis is the independent variable affects the rate of evaporation such that it may either increase or decrease in such a way that it will not remain the same.

Our hypothesis was correct as the rate of evaporation did not remain constant when the different variables, increase in wind, decrease in amount of light, decrease in temperature of hotplate, decrease in surface area and decrease in purity, were changed,

4.4 Areas for improvement

We could have placed the experiment for wind in a more reliable environment. The method for the testing of wind was to open the windows and turn on the fans. In this context, we are conducting the experiment with the assumption that the wind from the outside environment will remain relatively constant. Should the wind have changed, it could have affected our results greatly.
We could have ensured the wind remained relatively constant by either measuring the speed of the wind blowing by using a data collector, or closed the windows and used a fan directly at the set-up instead of a ceiling fan.

The same goes for the experiment for light. We conducted the experiment in the same room with the lights off. While the difference in light is considerable, the best method would have been to place the set-up in an opaque cardboard box. This way, there would be absolutely no light touching the set-up. However, doing that would have been very risky and might have resulted in a fire, as cardboard is flammable and we were dealing with heat.