Objective:

Solar energy is a type of renewable energy that can make your lifestyle more sustainable, especially if you are looking to reduce your footprint. In fact, you may have seen solar panels on homes in residential areas – these panels collect solar energy from the sun and convert it into solar power to power our homes, any excess any is either fed back to power grid or even sold back to power companies. In lab 5, we had the opportunity to take solar energy into the laboratory setting by introducing a new piece of equipment, the NXT with a light sensor. The goal of the lab is to gain hands-on experience on observing how solar energy is absorbed when manipulated in a lab setting.

Part I: How Distance of Light Affects Intensity and Voltage Output

In the first part of this lab you will be observing how moving a flashlight at varying distances from the NXT light sensor will effect the voltage output. For this component, the hypothesis is that as the flashlight is moved further away, the solar panel will generate less voltage.

Procedure: 

1. Obtain a solar cell, one voltage probe, one adaptor and one NXT with a light sensor. Make sure that the NXT Robot is operating with a functioning battery.
2. Get a light source, this can be a flashlight or an smartphone flashlight.
3. Obtain a ruler from the professor
4. Conduct a test run. You will need to open the file solarlab1.vi in order to measure the voltage output and light intensity throughout the experiment. You must understand how to operate Lab View and open the Excel sheet to view outputs before continuing to step 5.
5. To vary light intensity, you will be using the smartphone flashlight and ruler to hold it at different distances from the light sensor.
6. Since we want to observe how much voltage is generate at a zero (o cm.) distance, put the phone with its flashlight on, flat against the light sensor.Record results in Table 1 in your lab notes.
7. For next five trials, you will be moving the phone’s flashlight exactly two centimeters further away each time. Pay attention to your results, as this should result in a logical trend. Record results in your lab notes; rounding results to two or three significant figures should be acceptable for the graph.
8. In Microsoft Excel, input your results to generate a scatterplot. Be sure to insert a trend line and label all axes.

Table 1. Distance and voltage output 

Table 1 shows that the results have created a smooth trend line. As the light source was moved further away from the light sensor, the amount of voltage created decreased. Do you think that this observation was translate the same onto the generation of solar power from solar panels?

Part II: How Light Filters can Effect Voltage Outputs

In Part II of the lab, we will get to experiment with color and light. Luckily, for students who are currently taking lighting design courses, their lighting filter kits came in handy. The hypothesis for this part was that warm tones would cause a greater amount of voltage to be generated.

Procedure:

1. Obtain a solar cell, one voltage probe, one adaptor and one NXT with a light sensor. Make sure that the NXT Robot is operating with a functioning battery.
2. Get a light source, this can be a flashlight or an smartphone flashlight.
3. Get light filter swatches from the professor if you do not already have them. You will need a pink, red, yellow, and blue.
4. Unlike part one you will only be conducting for runs, one for each color. Be sure to record the results in a second table in your lab notes.
5. To visualize your results, input your results in Microsoft Excel once more and create a bar graph. Each color should have a separate bar.
6. Since Excel does not allow you to insert colors to each bar separately, you may insert shapes and color fill to match each color filter.

 

Table 2. The relationship between light intensity and filter color.

Conclusion

By forming a hypothesis for each part of the experiment, I was able to form a better understanding of how to use the lab equipment and familiarize myself about the various ways that we as humans, can change solar energy and light. As observed in part one, the hypothesis was proven correct since the increase in distance between flashlight and light sensor has an inverse relationship with the amount of voltage produced. In part II of the experiment however, the hypothesis was proven wrong since warmer tones such as red and yellow did not generally produce more average voltage. This leaves gaps in the information gathered from this exercise since we do not know why the pink and blue filters resulted in a large amount of voltage production. Further exploration into this topic would probably improve the analysis provided in this report. Also, it might be interesting to see what would occur had we chosen different colored filters, such as green or purple. Overall, it was an interesting observation to visualize the relationship between light and color.