yiler-huang-reflection-on-the-experimentation-process [Light]

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====== Essay about own science experiment =====

By [[yiler-huang| Yiler Huang]]

This semester, one of the main topics we have studied was the characteristics of ultraviolet (UV) light. We learned that one of the major sources of UV light comes from the sun, and they can be measured by a device called an UV sensor. We each assembled our own UV sensors and designed experiments to test our hypotheses about the nature of UV light. My hypothesis speculates that smoother surfaces reflect more UV light, and the measures will be higher when the sensors are directed towards smoother surfaces and lower when directed towards rougher surfaces. Because smoother surfaces reflect more visible light, it is also reasonable to believe that smoother surfaces also reflect more UV light. We tested our UV sensors in different locations with different ground textures such as basketball court, grass, parking lots, and wood planks. 

In order to prove my hypothesis, I designed an experiment. The purpose of the experiment is to test the amount of UV light reflected from different surfaces, and it was executed in the following procedure. First, we found suitable testing locations with different ground textures. Second, we pointed the UV sensor toward the surface of the ground and recorded the UV index it displayed every half seconds for 30 seconds. Finally, we repeated the procedure multiple times until we tested on all the different kinds of surfaces. The data collected were organized and analyzed into tables.

{{:yiler-uv-reflect-2.jpg?400|}}

//Us gathering UV data on Yangming Mountain//

My findings was that there isn't a direct relationship between the smoothness of a surface and its reflective property. Some smoother surfaces are more reflective than rougher surfaces but some are not. During the experiment, we tested on two smooth surfaces in the form of concrete and wood planks, and two rough surfaces in the form of grass and asphalt. The result was that the measurements on concrete and grass were higher compared to the measurements on asphalt and wood planks, which does not match my hypothesis. I believe that the reason was that locations we had gathered the data were of different altitude, humidity, and cloud cover, which are major factors that can affect the measurement of UV light and affect the measurement of the data.

After we collected our data, we discovered that there may be factors that would make our data less accurate. We discovered that our UV sensors have upper limits of 3.98 to the UV index values they can collect, which might result in inaccurate data when the actual value is higher than the upper limit. However, this problem didn’t seem to affect the results of my experiment. This is because my experiment required the sensors to be facing towards the ground, which means the values collected will be much lower than if the sensor was facing up.

{{:yiler-uv-reflect-1.jpg?400|}}

//Us testing our UV sensors in Taipei Expo Park//

On the whole, I believe that the biggest success in this experiment was the way the data was recorded. The table format makes the comparison of the data clear, which saves a lot of effort and time. On the other hand, there were also some things about the experiment that could be done better. For example, the result might be more accurate if the data were collected in locations of similar altitude and humidity. Also, I believe that we should have tested our sensors more before performing the experiment so we could eliminate the potential problems that could affect the result of our experiments. Overall, the conclusion of the experiment might not be an accurate assumption to the relationship between ground texture and the reflection of UV light due to the difference factors other than ground smoothness when executing the experiment. If we put more attention on keeping the consistency of the environment we are testing in, we might be able to get a better understanding of the relationship between ground textures and reflected UV light.