Tag Archives: Light

Can you change the color of oudin coil sparks?

An Oudin coil can take the energy out of your outlet and create sparks you can see! It’s sometimes called a mini tesla coil. The sparks on them usually look violet.

Oudin Coil spark

If you know the visible light spectrum, you might know that violet light is the most energetic color of light. 

Oudin Coil light

The oudin coil looks like it’s putting out a lot of energy, but there’s a different reason for the violet sparks. In fact, the color of the sparks don’t always have to be violet like most people see. To demonstrate, check out the oudin coil when it sparks in something else, like carbon dioxide. An easy way to get a bunch of carbon dioxide in one place is with its solid form — dry ice!


When surrounded by CO2, the sparks from this oudin coil are clearly a different color!

Oudin Coil ice sparks

The reason for the color shift is because of what is surrounding the oudin coil. Our air is less than 1% carbon dioxide. When sparking in air, the coil surrounded mostly by different gases (mainly nitrogen and oxygen). The answer to why that makes a difference is the same answer as to why different gases glow different colors when you put a lot of energy into them. 


light colors

If you split apart this light, with something like diffraction glasses, you’ll see each type of gas has a unique spectrum of light. The study and use of this phenomenon is called spectroscopy.

Lights and glasses

Spectroscopy is a way of identifying gases, and it’s how we know what far away things like stars are made out of! On a tiny molecular scale, CO2 and what makes up our air are fundamentally different, and will create differences we can see… if we are clever enough to notice. By playing with this oudin coil and looking at colors, we’re revealing secrets about a seemingly invisible world.

Written By: Amanda Williams


To Infinity Table and Beyond

Light, it’s properties, and the ways it can be manipulated are as fascinating as they are beautiful. It can be bent, slowed down, absorbed, and reflected. It turns out that the study of optics looks into all of these different interactions. But what happens when you want to mix the science of optics with a bit of real-world fun? You get an infinity table!

Infinity tables are named as such due to the illusion that the lights go on forever down into the depths of the table. But how can that be?

Infinity Table

To answer this, you not only need to know how the table was made, but also what optical properties those materials have. The three materials that makes these tables unique are LED lights, a normal mirror, and a two way mirror. The LEDs of course provide the visually pleasing light source. The normal mirror on the bottom of the table allows for the light to be completed reflected back up. And finally, the two way mirror allows for half of the light to escape the box of the table, and the other half to be reflected back down.

Because half of the light can escape through the two way mirror, with each bounce, half of the light is lost from the box. This is how the light appears to grow dimmer as you look down further into the apparent depths of the table.

Infinity Table 1

These tables are not the easiest to make at home, however it is not impossible. A simple home goods store may have all of the supplies needed. Just be sure to have adult help and supervision if you are to attempt this, given that glass is involved.

Written By: Mimi Garai

Fiber Optics: Continuing the Light Discussion


fiber optics


fiber optics 1


fiber optics light


fiber optics light 1



Written by: Mimi Garai

Light: Just Flip It and Look You Will See

It is no surprise that we experience and use scientific phenomenons every day. But, did you know that our eyes do that too? At camp, we have a science experiment that demonstrates how our eyes take in light. This hole in the wall is a great model for an eye. Your eye has a few major components: cornea, lens, iris, pupil, retina, and macula, to name a few. For our purposes, let us focus on the iris and pupil. The pupil in an eye is basically just a hole. The iris is a muscle that can expand and contract to change the size of the pupil. The purpose of the pupil is to allow light to enter your eye.


light eyeLight, on Earth’s scale, travels in straight lines. So how does any of that light ever make it into your eyes for you to see the world around you? The key is reflection. Light bounces off of objects, and if it bounces just right, that information will make it all the way to you. However, the only light you will ever see are the rays that make it all the way through those tiny holes.

So why is the image that is formed upside down? Due to light traveling in straight lines, when the light that bounces off of someone’s head, that same information makes it through the hole. Any other reflection of light will slam into the wall, unable to pass along the data. Same thing goes for light bouncing off of someone’s feet. Because the light is entering through the small hole, it must intersect and thus the image is inverted. However, we don’t see the world upside down. Our brains have adapted to this phenomenon, and flips the images automatically! Our brains are amazing!

light more

Written By: Mimi Garai

Look up and Constellations

A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere. They typically represent animals, mythological people, gods or creatures. There are 88 modern constellations, but just because those are the ones that are recognized doesn’t mean that one you make up is less valid.

The stars that constellations are comprised of are not necessarily stars that are near each other. So how do they appear that way? It’s all about perspective.


Take for example, The Big Dipper, an asterism in Ursa Major. An asterism is a smaller part of a constellation, usually with more noticeable stars. The Big Dipper is composed of seven bright stars: Alkaid, Mizar, Alioth, Megrez, Phecda, Merak, and Dubhe. Together, they appear to be in the shape of a spoon (use your imagination). However, they are all different distances away from Earth as well as from each other. Their distances from Earth respectively are roughly: 104 ly, 78 ly, 82.5 ly, 80.5 ly, 83 ly, 79.5 ly, and 123.6 ly.  

constellations gif

But if you simply change your perspective, or location from which you’re looking at them, then the picture changes! Unfortunately, since we are all on Earth, our perspective can not move enough to make a big difference.

Written by: Mimi Garai

Gravitational Lensing

gravityMost of us have experienced using a lens in some way, whether it was using glasses, cameras, or our favorite, telescopes. A lens is a piece of glass or other transparent substance with curved sides for concentrating or dispersing light rays. They have the ability to bend light! Did you know that gravity can bend light in the same way? We call this gravitational lensing; when a large massive object, like a blackhole or galaxy, passes in front of our view of a distant light source and a distant galaxy. It bends the distant light in different ways, sometimes creating two or more images or creating an Einstein ring, a complete ring of the image.


gravity 1

The glass shape at the bottom of the stem of a wine glass, and looking straight through the glass has almost exactly the same optical properties as a massive galaxy or blackhole!

When you pass the glass over a light source or picture, it distorts the light into an Einstein Ring. This is one way Astronomers know about dark matter! According to Einstein’s theory of general relativity, the presence of matter (energy density) can curve spacetime, and the path of a light ray will be deflected as a result.

gravity 2

Written by: Mimi Garai

Watch what happens: LED in Liquid Nitrogen

It wouldn’t be surprising if nitrogen was your favorite elements. N2 is the most common molecule found in our atmosphere, making up roughly 78% of it. But here at camp, we have a different reason for why it is one of our favorite things to have around. We have a ton of liquid Nitrogen on camp and love using it to freeze things. We wanted to see what would happen when an LED (Light Emitting Diode) was submerged in the -321˚F liquid.

It turns out that something pretty cool happens… it changes colors! But why would cooling it down, taking energy away from the LED allow the color to change in a more energetic direction?


To answer that we need to know how LEDs work. They are two-lead semiconductor light sources that emit light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes on a positive or negative band within the device, releasing energy in the form of photons.


When an atom is at rest it’s electrons are at the lowest energy state possible. With LEDs, an electron is shot in, hits another electron which increases its energy, hopping up to the opposite band. When it starts to rest enough, it falls, giving off a photon (light particle). The bigger the hop in energy state, the greater the fall will be, and therefore the more energetic the photon will be.


The electrons start off with a bit of thermal energy, but when submerged in the liquid Nitrogen some of the thermal energy is removed. When the thermal energy is removed it allows the distance between the bands (the band gap) to physically increase which in turn will increase the fall of the electron, increasing the frequency of light!

Written by: Mimi Garai

The Cleaning Secret of Bleach


Bleach 1





More Fluorescent Bubbles!

Can’t get enough of bubbles? Here at AstroCamp we love playing with them too! This is a great DIY that you should definitely try at home. All you will need to make fluorescent bubbles is a blacklight, bowl, dish soap, ink from a highlighter, a little water, and a bubble wand. Then let the fun begin!


But what are you really seeing? We know that can have a funny way of working sometimes, and fluorescence is one of those times. Fluorescence is a property that only some materials have. It is the property of absorbing light of a short wavelength and high energy, and then emitting it at a longer wavelength and lower energy. This is a type of luminescence which is the emission of light due to a chemical reaction, electrical stimulation, or stress on crystals.

For the case of the fluorescent bubbles, the violet and ultraviolet light interacts with the highlighter fluid. Don’t worry, it is a low energy ultraviolet that will not harm you. Ultraviolet light is too high of an energy for humans to see. The highlighter fluid absorbs that high energy light, and then emits its own lower energy, visible light, which we can see as the impressive glow! Try it out with different colors to experiment which colors of highlighter fluid works best.

fluorescent flower

But where else is ultraviolet found? Did you know that the sun is the main source of ultraviolet light? There are actually some animals on Earth, like reindeer and butterflies that can see in the ultraviolet spectrum, and some flowers that have patterns in their petals that can only be seen in the the ultraviolet. So the next time you are outside on a bright sunshiny day, get your fluorescent bubble solution out and try to see the world through a new filter.

fluorescent daisy

How it works: Pyrex Glass vs. Vegetable Oil





