SCI 184 Legos

Throughout the last part of the course my group mates, Eryn Gordon and Charles Iwuc, and I worked on a replicating a wind turbine. The goal of our project was to test different wind speeds in order to calculate watt, voltage, and joules. We wanted to prove that when the electric fan was set on high, it generated a high voltage and wattage that was stored in the turbine.

We first started off by building the turbine model.

After completing the wind turbine, we placed our model in front of an electric fan, about a foot away, in order to create wind. We then ran six tests per fan speed (low, medium, high) each lasting ten seconds (total of 3 minutes). We recorded the voltage, acceleration and watt after each ten second run, as shown on the tables below.

Low Power

Medium Power

High Power

After completing all of the runs we found that, the more we increased the fan speed the more our model accelerated therefore producing more wattage which was stored in the turbine and used to power it without the help of the electric fan.

On Monday December 10, 2012, we set up our project and let two other groups test it out while we tested two other groups’ projects. We first visited the group who worked on the  “World’s simplest motor.” There we created a homopolar motor and tested how the magnets affected the rate of rotation, by wrapping a copper wire around a screwdriver and attaching it to a battery that had a magnet on both ends. After that we continued on to the “Potential and Kinetic Energy” group where we tested how much kinetic and potential energy balls with different masses had depending on where there are placed. We placed weighted balls at different points on a ramp and rolled them to see if they could rip throw tin foil and tissue paper.

Overall we were impressed with all the different projects and enjoyed this experience. I enjoyed working with Eryn and Charles on this project and have learned a lot in this class and project.

Last Monday, we conducted an experiment involving solar cells, also know as photovoltaics, in order to see how the light intensity and voltage output affected each other. Photovoltaics are one of the green energy alternatives we learned about in class.

My partner and I  first started off by connecting the necessary cords to NXT adaptor and the computer in order to track the results of each run. We then started off with no light then increased the distance of the light from 0 cm to 18 cm holding it for 30 seconds each time. This measured the intensity and energy of the light, the closer the light the higher the intensity and the farther the light the lower the intensity.  We also experimented with a red color filter at 10 cm and and a green filter at 12 cm to see how that effected the output and intensity.

During our last class my partner and I experimented with a generator/flashlight that stored energy and powered up by shaking it. After we connected the generator to the computer, we shook it a few times for 30 seconds each time alternating the speed and therefore the number of shakes. We counted the number of shakes, recorded the voltages and calculated the sum of the squares. We found that the faster we shook and the greater the number of shakes the greater energy produced to power the generator. We then plugged our number into an excel sheet and graphed it.

Our results:

September 24th’s lab experiment consisted of calculating potential energy and acceleration. First we created a pulley by attaching weights to a wire wrapped around a wheel. We connected the robot to the computer in order to control the mass, speed, time, etc. and track our results. We first kept the force constant at 10 newtons and saw how it was affected by the weight change starting at .05 kg up to .25 kg. Later we kept the mass constant at 0.25 kg and tracked how it affected force and acceleration when force increased each time by 10.

This is what we came up with when we kept the force constant:

This is a graph of our results mass on the x axis and acceleration on the y axis.

This is what we came up with when we kept the mass constant:

These are our results for potential energy

During the second part of class on September 17th, my partner and I participated in the in class experiment which consisted of building a robotic car out of legos and then connecting it to the computer and making it work with the program.

After building it, we let the car run for 2 seconds each time, once at the speed of 75, once at 80, and once at 85.

These are the results from each trial.

Time        Power       Circumference       Number of Wheel Turns        R1        R2

2                    75                  .1595                            3.333                                      1128          1137

2                    80                 .1595                             3.575                                      1287          1298

2                     85                  .1595                            3.3611                                     1210         1219

Distance:      Power              Actual                  Calculated

75                    .570255                    60 cm

80                   .499804                   55 cm

85                    .536138                    56  cm

For percent error we used this equation:

(measure distance) – (computer calculated distance)/

(measured + calculated/2) x 100%

We then used it to calculate the percent error for each trial.

75 —->      (60 – 0.499804) / (60 – 0.499804 / 2) X 100%  =        54.991

80—->      (56 – 0.536138) / (56 – 0.536138 / 2) X 100%     =         56.990

85—–>     (60 – 0.570255) / (60 – 0.570255 / 2) X 100%     =         59.990

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