Party Science, Part 2: The Lights

If you haven't already, please read Party Science, Part 1: the Beats.

So, now that we’ve got the beats, what’s next? How about we get some lights to set the mood. Today’s installment: the lights.

Again we’ll start with a simple question: what is light? Simple question, not so simple answer. To skip a lot of gritty stuff, let’s just start with the premise that light is a form of electromagnetic radiation consisting of orthogonal electric and magnetic field components and behaving as a transverse wave while also as a particle… yeah. Anyways, there are many types of light bulbs that we can use for different effects. For typical houselights, incandescent bulbs with tungsten filaments that utilize blackbody radiation were used until recent years. Currently, compact fluorescent light bulbs (CFLs) are popular for efficiency reasons with LEDs on the rise. CFLs work by ionizing argon gas and mercury vapor with tungsten filaments by thermal electron emission to produce UV radiation. The UV radiation is then converted to visible white light by phosphors either on the bulbs or on their housing [1]. LEDs utilize the junction between semiconductor material doped with electron rich or electron poor elements relative to the semiconductor valence number (p-n junction) to produce light as the electrons from the negatively-doped material fall into lower-energy electron "holes" in the positively-doped material. With these typical lights we have some basic lighting. Now what are we going to do about colorful lights for that true party feel? The college DIY option would be to put colored plastic or something over house lights to get the same effect as a colored bulb at a fraction of the cost!

Fig. 1: Procedure for colored lamp perfection (Dornob)

But how does doing this produce colored light? The first thing to notice is that the colored filter is, in fact, colored (huh, imagine that). What this indicates to us is that whatever the material is made of or coated with, it is only transmitting light that comprises the observed color. In other words, the material is absorbing a portion of the visible spectrum of light and we see a net color as a result of this absence. This could be due to a number of factors, for example the presence of transition metal compounds or conjugated organics, but the general property that allows a material to absorb light is a possible electron energy state transition corresponding to a frequency in the visible spectrum. When applied, the colored filter acts on the white light emitted from the light source, filtering out the characteristic absent spectrum and producing a net color. And with our bargain colored lights in place, how about we go for a special effect to top it all off. Let's use some blacklights. Blacklights are fluorescent lamps tubed in black-coated glass to absorb most visible light and coated in phosphors that permit only UVA light (not UVB, which causes sunburn, or UVC, which is filtered out by our atmosphere naturally and would give you super sunburn, a.k.a. cancer) to exit. The UVA radiation produced interacts with phosphors in white clothing from laundry detergents, with natural phosphors in teeth and nails and with fluorescent clothing to produce the psychedelic colors that are associated with blacklights [2]. With beats and lights, our party is going strong.

Below I’ve posted a video of Russian hip hop artist Kristina Si that depicts multiple types of lights employed at a party. Take notes people.