Let there be light!

Chemiluminescence Demo Video

Read on to learn about what’s happening in the video above:

Our scientist pours two solutions, labeled Solution A and Solution B, into two separate beakers (these solutions are respectively a Luminol mixture and Hydrogen Peroxide). [NOTE: Luminol is a “versatile” chemical that happens to be very good at demonstrating the turning of chemical potential energy into radiant, or light, energy.] He empties the two beakers into the tube apparatus, turns the lights off, then the magic happens as the solutions combine to make a glowing liquid! THIS is chemical potential energy turned radiant energy.

Some glowing “stuff” gets its light by way of a reaction called chemiluminescence. Chemiluminescent reactions are chemical reactions that yield light without producing much heat, which we think is pretty amazing. What else undergoes chemiluminescent reactions? To list a couple of common occurrences: fireflies and lightsticks.

Firefly

Firefly. Photo courtesy of nativeplantwildlifegarden.com

Why are we particularly excited about glowing stuff? Because Pajama Jam is almost upon us (tomorrow night), and there’s going to be a ton of glowing stuff there – glow-in-the-dark bowling, glow-in-the-dark ring toss, glow-in-the-dark bead necklaces, and more! AND now you know why these things can glow without burning us – they are undergoing chemical reactions which yield light with the production of very little heat…unlike, say, the light produced by a conventional lightbulb.

Tickets for Pajama Jam are available online here. We hope to see you there!

 

Candy Chromatography

Turn your Halloween candy into an awesome chemistry experiment!

Materials:
Candy with colorful coating
Flat plate or piece of foil
Coffee filter
Water
Pencil
Tape
Toothpicks
Clear glass or jar

Procedure:
1. Cut your coffee filter into a square.
2. In pencil, draw a line about one inch from the bottom of the filter. Using equally spaced increments, write the color of each candy on the bottom of your coffee filter.
3. Place one drop of water on your plate or piece of foil for each colored candy you want to test.
4. Put a piece of candy on top of the water drop and allow it to sit and dissolve for about a minute.

Procedure: Place Each Candy on a Drop of Water

Procedure: Place Each Candy on a Drop of Water

5. Remove the candy.

Procedure: Place a Drop of Color on Coffee Filter

Procedure: Place a Drop of Color on Coffee Filter

6. Using a clean toothpick for each color, place a small dot of the colored water on your coffee filter about an inch from the bottom above the appropriate color label.
7. Let the drop dry and repeat 2 or 3 more times.
8. Place a small amount of water in your glass or jar.
9. Tape your coffee filter to the pencil and place it over your glass or jar so the bottom of the filter just touches the surface.
10. When the water reaches about an inch from the top of the coffee filter, remove the filter and let it dry.
11. Observe your results!

What Happened and Why?
As the water soaks into the coffee filter, different components of each colored dye are separated. As you can probably see from your results, some colors are made up of a mixture of dyes. You’ll also notice that some colors are pulled farther up your coffee filter than others.

This is all explained by the fact that various dyes have their own chemical compositions, each of which separate at varying rates. Additionally, each chemical therein absorbs different wavelengths of light and by default expresses the ones it does not absorb, meaning that those not absorbed are the colors our eyes can detect.

Results

Results

Internal Combustion

Combustion is defined as the chemical combination of two substances accompanied by the production of light and heat; simply put, to combust is to burn. Take a look at this six-second video of one of our Education staff members, Isaac, conducting an internal combustion reaction:

https://vine.co/v/hpMXAYMZqht/embed/simple

As you can see in the video, Isaac starts by placing a few drops of methanol [methanol: oxidized methane, a main component of natural gas] into an oxygenated polycarbonate plastic bottle. The bottle has been punctured by two metal conductors, carefully angled so as to avoid any dangers should they become dislodged. After dropping the methanol in, Isaac corks the bottle.

Next, he takes a Tesla coil (powered by electricity) and touches it to the tip of one of the metal conductors. Within a matter of seconds, a burst of heat and light pushes the cork out of the bottle at high speeds.

What exactly is going on here? Ultimately, this is a demonstration of how electrical energy becomes chemical, then radiant and thermal, then mechanical energy. It’s the same concept that is behind how our car engines work – to power car engines, a cycle of hundreds of these explosions must occur per minute, and they must be converted into rotational, rather than linear, motion (think in terms of pistons and crankshafts).

Four-stroke engine

Four-stroke engine; image created by Wikimedia user A7N8X.

In Isaac’s demonstration, the bottle is our closed chamber, the methanol is our fuel, and the Tesla coil serves as our initial source of energy. When Isaac puts the coil to the conductor, electrical energy is transferred to the metal. This energy wants to continue traveling along the path of least resistance, but there is a gap between our two metal conductors. The energy jumps this gap, yielding a spark which generates a chemical reaction between our oxygen and methanol. As the two react, they release light and heat; the heat causes the air in the chamber to expand. This expanding air is highly pressurized and must escape the container. Therefore, it searches for a means to do so – by way of our cork. The cork then blows off, showing us mechanical energy in action!

NOTE: In internal combustion chambers, the proper ratio of fuel to oxygen, known as the Air-fuel ratio, is crucial. This ratio determines the yield of your reaction.