Monthly Archives: January 2014

Simple Homemade Spectroscopy

I love chemistry. I get to play with fancy instruments, do some experimenting, and act all sciencey and stuff. Next week, for example, I get to play with a nice spectrometer and do some mathjitsu on spectral stuff. Anyway, I decided to see if I could build a simple spectrometer myself. Five minutes later I learned how to build a simple device out of cardboard, some tape, and a DVD. An hour later, and here’s my spectrometer:

Homemade Spectrometer

Homemade Spectrometer

This spectrometer was designed by–a nonprofit community science organization. The kit for the spectrometer can be purchased on Amazon, but I built mine from schematics provided by

It’s really an amazing spectrometer for its simplicity. Light enters a tiny horizontal slit at the front of the box and passes through a diffraction grating made from a piece of a DVD. Essentially, the light coming through the narrow slit hits the DVD which splits the light into the wavelengths that compose it. What you see looking through the DVD lens is the line spectrum of the light source. A good explanation of the tech and the underlying science can be found here.

So let’s take a look at a few emission spectra (Note: Usually you see spectra oriented horizontally, but these are oriented vertically… same thing different perspective):

Spectrum of sunlight through clouds

Spectrum of sunlight through clouds

Spectrum of Fluorescent Lightbulb

Spectrum of fluorescent light bulb

Spectrum of Incandescent Lightbulb

Spectrum of Incandescent Light bulb

I got these photos simply by holding the little homemade spectrometer up to my phone camera. I have a rather cheap phone camera so the spectra are not as well defined in the images as they are if I look through the spectrometer with eyes only. The really neat thing is that I can upload these images to where my spectra are converted into graphs. After calibrating my spectroscope with a fluorescent light, I can compare my spectra against each other and against spectra taken by others. It should be a very useful tool for home spectroscopy.

In the image below, I’m comparing the spectrograph of a white L.E.D. light (white line and color spectrum) with the spectrograph of the same light shining through dark green glass (red line). From this comparison we can deduce the absorption spectrum of the green glass. It shows that the green glass reduces the intensity of the light across the spectrum (i.e. the red line is lower), and it shows that the glass absorbs blue and violet from the L.E.D. (i.e. red line drops at the left side).

Perhaps the most interesting spectrum I saw was that of sodium in the flame of a butane lighter. First I made a sodium chloride solution by stirring ordinary table salt into hot water. Then I dipped a cotton swab into the solution, held it over the flame of a butane lighter, and watched it through my spectroscope. At first all I saw was the full spectrum of the burning butane, but all of a sudden a yellow line much brighter than the rest of the spectrum appeared. The yellow line was the spectral signature of sodium. I’ve done this experiment in chemistry lab, but to see the same results at home with a homemade spectrometer is magical.

Getting the spectrograph of a fluorescent light.

Getting the spectrograph of a fluorescent light.

Categories: Poor Mad Science, Science | Tags: , , , , , | Leave a comment

I did the S-word

Public SpeakingI feel almost embarrassed for the lack of updates in the last several months. I’m getting married in a few weeks, and trying to juggle work, school, friends, and wedding planning leaves very little time for writing. I promise to update this blog more often in the near future, but I just wanted to pop in today and share some exciting news.

In my life I have scaled some of the tallest mountains in Montana, I’ve left the oppressive culture that is the Amish, I’ve developed computer software and Android apps, I’ve written a book, I made member of the International Society for Philosophical Enquiry (way cooler than Mensa), I landed a white-collar internet marketing job with only an eighth grade education, I convinced a beautiful girl to fall in love with me, but today… today… I stood in front of about thirty people and gave a speech.

To put this feat into context, you should know this–I suffer from debilitating social anxiety, or maybe I’ve just convinced myself of that. Years ago I quit accounting school partially because I couldn’t handle the pressure of the required speeches/presentations, but mostly because I decided I hate accounting.

Here I’ve made a cute little function that illustrates the effect of social anxiety on I.Q.:

Social Anxiety Function

Isn’t it pretty? I call it the Social Anxiety Function, where a is your anxiety factor and b is your I.Q. when you’re all alone. It gives your I.Q. as a function of the number of people that are looking at you.

Given my specific conditions, this function shows that my I.Q. hits zero when there are 5 people watching me. Any more than that, and it goes negative, which seems impossible given how I.Q. is measured, but trust me, it’s very real. If six people are looking in my direction, the speech and behavior that I manifest are not possibly the output of anything with positive intelligence.

Sometimes, when I’m walking down the aisle of a grocery store I start walking funny because I think the person I just passed has turned, and is watching me. I walk funny because I’m concentrating so hard on walking like a normal person. I don’t have any kind of physical disability–when I’m all alone I walk perfectly fine, but have someone watch me and I develop a limp because I’m trying so hard not to.

I would like to see a psychologist, but I’m deathly afraid that I wouldn’t be able to talk. I’m usually okay when it comes to answering questions, but it’s very difficult for me to initiate conversation or to say anything that’s not the answer to a question. I think I suffer from some weird form of mutism.

Hopefully, that gives you some idea of the magnitude of the accomplishment I’ve made today. I stood in front of a class of 20-30 fellow students, and I gave a speech about myself. I had no choice in the topic. But, it wasn’t as bad as I had feared it would be. I ended up with a pretty good grade, although the professor told us that she was going easy on the grading for our first speech.

I practiced my speech over and over again when I was alone at home. I actually did pretty good when it came time to speak. I forgot a few things I had planned on saying, and I fumbled my introduction, but other than that it wasn’t too bad. I attribute my success almost entirely to those rehearsals, and I really appreciate the friends that told me to practice, practice, practice! I only practiced my speech when I was alone. It would’ve helped even more if I would have rehearsed in front of my housemates, but I couldn’t do it. I couldn’t even rehearse my speech in front of my fiancee–that’s how weird it makes me feel to stand up and formally address by voice my fellow humans.

Tonight, I feel exhausted. You’d think I ran a marathon. This speech course is a required course for me, but getting through it will be worth it, I think. The sense of accomplishment I felt after the nausea had worn off was great. Now I know that I can do anything. Who knows, maybe I could even learn to function as a social animal despite my anxiety.

Categories: College, College Life | Tags: , , , , | Leave a comment

Create a free website or blog at

Sean Carroll

in truth, only atoms and the void

The Intrepid Mathematician

Reading, writing and arithmetic.

The Life of an Ex-Amish Girl

My thoughts and feelings

What's new

Updates on my research and expository papers, discussion of open problems, and other maths-related topics. By Terence Tao

Grownass Math

Bringing some fucking style to the math game.

elkemental Force

Energy, Software, and Anything in between.

a political idealist.

Lidia. 21. A college student with a blog dedicated to the thoughts and ramblings of the mind.

Many Worlds Theory

In one universe, this blog is about quantum mechanics. In another universe, it is not.

The Cheerful Chemist

Fascinating molecules and new developments in chemistry

Math with Bad Drawings

Lover of math. Bad at drawing.


Someone hire me. Please.

The Lazy College Student's Survival Guide

As a self-identified lazy college student with a High GPA. I will share my secrets to having an effective college education while not losing much sleep or life. Let's Go


Experience the joys of university life with me!

Why? Because Science.

Combating Stupidity Since 2012

My Digital Destiny

From carbon to silicon...