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Ella WilsonTitle

IB Physics Period 5June 6, 2011

Research Question:

What is the relationship between the transmission of light due to its wavelength,

and the time it takes for the fan to make one cycle?

Design:

The aim of the experiment is to research the relationship between the transmission

of light due to its wavelength of light and the time it takes for a fan to pass through a

Photogate, which represents how much power each wavelength produces. Setting up a

circuit with a light bulb shining down onto the circuit, I will hook up a fan to the circuit

for power, and a use a Photogate to measure the number of times it turns. Using different

filters I will be able to take different data for different wavelengths, this will enable me to

investigate the relationship.

Variables:

Independent Variables: Percentage of light transmitted

Dependant Variables: Number of times the fan turns

Control Variables: Distance from lamp to panel, Light bulb, Fan, Distance from

fan to Photogate, Circuit

Apparatus and Materials:

Solar Panel Light Fixture

60-Watt Light Bulb Fan

iMac Computer Photogate

4 Filters, Black, Red 27, Red 19, Yellow Wires

Logger Pro 3

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Procedure:

Labeled Diagram:

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Method:

I will set up the apparatus as shown in the diagram above. I will connect the solar

panels to the fan in series to power the fan. I will make the distance from the lamp

to the solar panel 0.10 m and keep it constant. The distance from the Photogate to

the tip of the propeller will also be kept constant at 0.10 m. I will set up Logger

Pro 3 to graph the time it takes for one propeller to pass to the next one when I

press the collect data button. I will collect data for the first trial without using a

filter. Then for the next four trials I will repeat this process using the, black,

yellow, red 27 and red 19 filters. I will collect and record this raw data.

Data Collection:

Filters Time (s)

Yellow 0.025194 0.027720 0.045488 0.047984 0.065844 0.068390 0.086124 0.088620

Red 27 0.019483 0.021983 0.039900 0.042431 0.060185 0.062684 0.080615 0.083183

Red 19 0.025309 0.027784 0.045290 0.047784 0.065124 0.067584 0.085108 0.087584

Black 0.027684 0.030516 0.050684 0.053484 0.073827 0.076698 0.096826 0.099684

None 0.020488 0.022918 0.039582 0.041983 0.058783 0.061192 0.077884 0.080283

Time for one cycle of the propellers is e.g.,

(0.047984 s) (0.027720 s) = 0.020264 s

Filters Time (s)

1 2 3 4 5

Yellow 0.020264 0.020396 0.020406 0.020240 0.020300

Red 27 0.020448 0.020285 0.020253 0.020430 0.020499Red 19 0.020000 0.019834 0.019800 0.019984 0.020000

Black 0.022968 0.023143 0.023214 0.022999 0.022986

None 0.019065 0.019201 0.019209 0.019101 0.019091

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The average time for one cycle is e.g.,

t avg= (0.020264 s) + (0.020396 s) + (0.020406 s) + (0.020240 s) + (0.020300 s) =

0.101606 s

0.101606 s 5 = 0.0203212 s

Filters Transmission % Average Time

(s)

Yellow 85% 0.0203212

Red 27 4% 0.0204384

Red 19 20% 0.0199236

Black 1% 0.023062

None 100% 0.0192417

Time Uncertainty

To find the uncertainties I will multiply the value of the ranges by one half: e.g.,

(0.020406 s) (0.020240 s) = 0.000166 s

0.000166 s 0.5 = 0.000083 s

Transmission Uncertainty

There is no uncertainty for the transmission because it was taken from a literature value.

Filters Transmission Average Time (s)

Yellow .85 0.02032 0.00008

Red 27 .04 0.02044 0.00002

Red 19 .20 0.01990 0.0001

Black .01 0.02310 0.0001

None 1 0.01924 0.00007

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Control Variables

Distance from lamp to panel = 0.10 m

Light Bulb = 60 W

Distance from fan to Photogate = 0.10 m

Graph of Data:

Conclusion:

The purpose of my experiment was to research the relationship between the

transmission of light and the average time for one cycle of the fan. Even though my

method was clear by using control variables, independent and dependant variables, there

was still no relationship. Because this graph does not have a linear, or curve to it we can

concur from this experiment that there is not a mathematical relationship between the

average time of one cycle and the percentage of light transmitted from the filters.

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Evaluation:

Because there was no mathematical model to base a hypothesis on, it was difficult

to see if there would be a mathematical relationship in this experiment. Therefore I

cannot derive an equation based on my data because it has no relationship. Perhaps there

was a systematic error, but I believe it was because there was no original mathematical

model to base my relationship off of. My data was very accurate because I used a

Photogate, which gave me accurate results with the computer software. I was able to keep

my control variables constant because I did not have to move the lamp or fan when taking

my data. I was not rushed when taking or processing my data so I do not believe there

would be an error there either.

Improvements:

One way to see if there was any potential relationship for my experiment would

be to take more data, and process it to see if a wide range of values had an effect on the

graph of the data. Or perhaps using even more different filters to find if there would be a

wider range of values.

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