After we have received all necessary materials for the experiment we can truly begin collecting useful data. The physical set up of the experiment is the same as the solar cell experiment, which we did in class. We will have an NXT microcontroller with the same code as the solar cell Labview code. We will have a voltage probe connected to one of the ports in the NXT microcontroller and the other end is connected to the wires of the solar panels. We will collect the voltage output during a 10 second period (this duration time might be changed). We will perform 3 different trials throughout the experiment, each trial representing a different obstruction. The 1^st trial is considered a reference point because we will measure the voltage output when the solar panel is clean. The 2^nd trial we will pour water on the solar panels (they are encapsulated) to simulate rain and then take a voltage reading. In the 3^rd trial we will take some dirt and smudge it over the solar panel gently to mimic dust build up and once again take a voltage reading. It is important to remember that the light source is held constant during all trials and will be the same distance throughout the experiment. In between each trial, we will clean the solar panel since each student group will only be given 1 solar panel for the whole experiment.

Once we complete the trials, we will open up the data on a excel spreadsheet and create a bar graph of the averages of the voltages of each trial. What we should observe is the voltage decreasing in between the 2^nd and 3^rd trial. There shouldn’t be a very big voltage difference in between the 1^st and 2^nd trial. Now that we have a visual of the data we want to calculate about how many voltage is being lost in between the 1^st and 3^rd trial. In our solar panels the difference is going to be quite small, but in commercial/residential solar panels this difference is evident. After were done dealing with the data, we will ask students 2 questions to make them think more critically:

1. The most typical size for solar panels used for residential installations is 65 inches by 39 inches, while the common size for commercial applications is 77 inches by 39 inches. The solar panels we have provided are approximately 2.4 inches by 3.6 inches.

Estimate the voltage lost in a residential and commercial solar panel.

2. The majority of solar panels in commercial installations are maintained by individuals who physically clean each solar panel (similar to window cleaners). This method is expensive and tedious for the workers.

What are alternative approaches to cleaning solar panels that are less expensive and more effective? (Hint: Think Autonomous Systems)

            We are looking for your ideas so let your imagination run wild!