By Jacob Duvall & Ryan Rice

Light is an electromagnetic wave Meaning it is made up of a changing electric field and a changing magnetic field. When these two fluctuating fields are combined they produce an electromagnetic wave.

Electromagnetic Spectrum Visible Light is just a range of frequency of electromagnetic waves. If you increase or decrease the frequency (energy of the wave) you get different colors of visible light. Go even further and at the low frequency you will have radio waves and at the high end you will have Gama waves.

Minimum credit line: Image courtesy of NRAO/AUI and Image courtesy of Stephen White, University of Maryland, and of NRAO/AUI.(for details, see Image Use Policy).Image Use Policy). Radio~ 100m – 1m

National Solar Observatory at Kitt Peak, in Arizona. infrared~.3mm - 780nm

Image credit: NASA/JPL-Caltech/GSFC xray ~ 10nm nm

Image courtesy of unawe.org Visible light ~ 780nm – 380nm

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Like Feynman we also wondered about what information we are perceiving from our environment and how our brains interpret it. By isolating certain frequencies of waves we hope to gain a better understanding of this “great choppyness of waves” we experience on a daily basis. When formulating our question we considered infrared waves, or heat. These produce a definite physiological response by our bodies, i.e. sunburns. Might there be other bodily responses to other varying wavelengths of electromagnetic waves

Will higher frequencies of light induce a more alert state in subjects, while lower frequencies induce a more relaxed state? And in general, is there a measureable physiological response by our bodies when exposed to visible light.

If the subject is exposed to higher frequencies of visible light for 60 seconds the Blood Pressure reading and EKG reading will be higher than if the subject is exposed to lower frequencies of visible light for 60 seconds.

Controlled variables: time exposed, placement of ekg, and blood pressure sensors, cuff pressure (160 mm Hg), dark room, no external stimuli. Independent variable: light source, defined in units of frequency and color temperature Dependent variable: physiological response as defined in readings of blood pressure and heart rate

- EKG probe - Blood pressure probe - Light sources: digital screens with varying frequencies of color - Computers x 2 - LoggerPro - Dark Room - Computer camera - HDMI cable

We will expose test subjects to 4 different visible light frequencies (colors) for a controlled amount of time (60 seconds). During this time we will monitor each subject’s heart rate and blood pressure in real time with an EKG sensor and a Bloodpressure sensor.

Violet 380 nm Yellow 570 nm Red 780 nm White All Wavelengths

1.Start Probeware data collection tools and LoggerPro on the laptop 2.Have test subject sit down in the testing area 3.Attach EKG and Blood pressure cuff sensor 4.Run the Control experiment a.Lights are turned off in testing area b.Pump up cuff pressure on the BP sensor to 160mmHG c.Test subject closes their eyes for 60 seconds d.Run data collection for 60 seconds e.After data collection has stopped release the remaining pressure in the BP cuff. f.Save your results.

Sample Data from LoggerPro

Subject NameViolet (mV)Yellow (mV)Red (mV)White (mV)Control (mV) Brady B Brandt H Brian F Clay G Kyle R. Meredith R Kevin M Sarah C John C Average (mv)

Subject NameViolet (mV)Yellow (mV)Red (mV)White (mV)Control Brady B Brandt H Brian F Clay G Kyle R. Meredith R Kevin M Sarah C John C Average (mv)

Test SubjectViolet BPMYellow BPMRed BPMWhite BPMControl BPM Brady B Brandt H Brian F Clay G Kyle R Meredith R Kevin M Sarah C John C Avg

Column Chart of Data from Table 1.3

First we want to emphasize that we took the utmost care to ensure each trial was run as similarly as possible without any deviation. However, there are things outside our control, For example, a dump truck driving by or neighbors making loud noises. We tried to keep these disturbances to the absolute minimum, but they were there. Ideally we would like to have a more controlled testing area for any future studies. In addition on a few readings the Blood pressure sensor lost too much pressure, this usually occurred in patients with smaller arms, in these cases the BPM was derived from their EKG by counting the discharge of electrical pulses. (This is considered a standard practice in hospitals and clinics.)

In addition, having to go out and find subjects, set up the experiment, was a major time constraint. Ideally we would have a set location and our subjects would volunteer allowing us to streamline the process. Sample size could be larger, if we were working with a research facility that had a large volunteer pool.

Again I would like to stress that our data set is indicative of this grouping only, further research is needed to make generalizations about larger groups. In this grouping a quantifiable difference is detected in the beats per minute or heart rate of the subject. In the Column Graph of the Blood Pressure Averages it becomes clear that as the wavelength of light decreases the BPM also decrease.

Another way of looking at the data would be this graph.

Subject Name Violet YellowRedWhite Control Brady B Brandt H Brian F.***** Clay Kyle R Meredith Sarah C John C Kevin M Average

Blood pressure (mm Hg) color

Blood pressure (mm Hg) color

Noticing the EKG table results we confirmed that there is only separating each result and therefore we believe this to be inconclusive, given our instrument sensitivity, to conclude anything from these results. Therefore we look specifically at the Beats Per Minute when considering this grouping. Given this data we conclude that for this group there was a noticeable, measurable, and consistent physiological response to what wavelength of light you are seeing.

Another thing that was very interesting is that white light also was higher than the control, due to its nature, and because it is a mix of all colors we did not graph this light source. Also the Control (no light) was higher than red light indicating that red light (for some people) may even have a calming effect on the heart.

We believe that this topic has vast array of future studies that would yield very interesting results. Testing more colors, and testing different light sources such as: sunlight, tungsten bulbs, fluorescent bulbs. Also testing for extended amounts of time: what about people who work in fluorescent lighting up to 8 hours a day. One study that was done recently looked at E-readers which emit a blue-violet light wave, and sleep apnea, and circadian rhythm Another study looked at light and macular degeneration