Science Projects & Models

COLORED SMOKE BOMB

The classic smoke bomb is a great project for the home or lab, producing lots of safe smoke, with purple flames. If you get dye and consider the shape of your creation, you can make a smoke bomb that billows clouds of brightly-colored smoke. This project is easy and safe enough to at home. Adult supervision is required

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Colored Smoke Bomb Materials

• 60 g (3 tablespoons) potassium nitrate (sold as saltpeter in garden supply shops)
• 40 g (2 tablespoons) sugar
• 1 teaspoon baking soda
• 60 g (3 tablespoons) powdered organic dye (such as synthetic indigo or an aniline-based dye, found in some craft & hobby shops; not common water-based dye)
• cardboard tube (best is an iced push-pop tube (eat the treat first), or you could use a toilet paper roll or section of paper towel tube, or even a rolled/taped paper tube)
• duct tape
• pen or pencil
• firework fuse (hardware, rocketry, construction, or hobby shops, or scavenge it from a firework)
• cotton balls
• saucepan

Make the Colored Smoke Bomb Mixture

1. Mix 60 g potassium nitrate with 40 g sugar in a saucepan over low heat. It's a 3:2 ratio, so if you don't have grams, use three large spoonfuls of potassium nitrate and two large spoonfuls of sugar (3 tablespoons and 2 tablespoons, if you feel the need to be precise).
2. The sugar will carmelize and brown. Stir the mixture continuously until it resembles smooth peanut butter.
3. Remove the mixture from heat.
4. Stir in a spoonful of baking soda (rounded teaspoon is fine). The baking soda is added to slow down the combustion when the smoke bomb is ignited.
5. Add three large spoonfuls (3 tablespoons) of powdered organic dye. Blue dye and orange dye are said to produce better results than the other colors. Stir to mix well.
6. Construct the smoke bomb while the mixture is still hot and pliable.

Assemble the Smoke Bomb

1. Fill a cardboard tube with the warm smoke bomb mixture.
2. Push a pen or pencil down into the center of the mix (doesn't have to be all the way to the bottom but should be enough that the pen stands in the mixture). You could use a different shape, but the cylinder works really well.
3. Let the mixture harden (about an hour).
4. Remove the pen.
5. Insert a firework fuse. Push pieces of cotton balls into the hole to tamp the fuse securely inside the smoke bomb. Be sure there is fuse left outside of the tube so that you will be able to light your smoke bomb.
6. Wrap the smoke bomb with duct tape. Cover the top and bottom of the tube, too, but leave the hole area with the cotton and fuse uncovered.
7. Go outside and light your smoke bomb!

Science Projects & Models

CHALK CHROMATOGRAPHY

Chromatography is a technique used to separate components of a mixture. There are many different types of chromatography. While some forms of chromatography require expensive lab equipment, others can be performed using common household materials. For example, you can use chalk and alcohol to perfom chromatography to separate the pigments in food colorings or inks. It's a safe project and also a very quick project, since you can see bands of color forming within minutes. After you've finished making your chromatogram, you'll have colored chalk. Unless you use a lot of ink or dye, the chalk won't be colored all the way through, but it will still have an interesting appearance.

Chalk Chromatography Materials

• chalk
• alcohol (isopropyl alcohol or rubbing alcohol seems to work best)
• ink, dye, or food coloring
• small jar or cup
• plastic wrap

1. Apply your ink, dye or food coloring to a piece of chalk about 1 cm from the end of the chalk. You can place a dot of color or stripe a band of color all the way around the chalk. If you are mainly interested in getting bands of pretty colors rather than separating individual pigments in the dye, then feel free to dot multiple colors, all in the same place.
2. Pour enough rubbing alcohol into the bottom of a far or cup so that the liquid level is about half a centimeter. You want the liquid level to be below the dot or line on your piece of chalk.
3. Place the chalk in the cup so that the dot or line is about half a centimeter higher than the liquid line.
4. Seal the jar or put a piece of plastic wrap over the cup to prevent evaporation. You can probably get away with not-covering the container.
5. You should be able to observe the color rising up the chalk within a few minutes. You can remove the chalk whenever you are satisfied with your chromatogram.
6. Let the chalk dry before using it for writing.

Science Projects & Models

FIRE BREATHING

Firebreathing involves breathing a fine mist of fuel over an open flame to form a fireball. It's playing with fire in a big way, so there are obvious risks involved. It's adult-supervision-only time here, okay? I strongly advise you never to attempt fire breathing with a flammable fuel because this carries a risk of the fire traveling back to you and setting you on fire. Additionally, most of the traditional flammable fuels are toxic. Here's how to breathe fire with a non-toxic, non-flammable fuel. You probably ought to try this project outdoors, not because of the risk of a fire, but because you're going to make a big mess with the fuel, which is corn starch.

Firebreathing Materials

• big container of corn starch
• big spoon
• big glass of water
• big flame

How to Breathe Fire

1. Fill your mouth with a big scoop of corn starch. Do not breathe in any of the corn starch! The biggest risk from this project is inhaling corn starch, which could damage your lungs (like any fine powder). Laughing is your biggest threat here. The corn starch doesn't have a bad taste, but the texture is every bit as nasty as whatever you're imagining.
2. Blow the corn starch out over a large flame. There is some skill to this: try to whistle out the corn starch. It's easy to blow out a candle or lighter, plus it puts your hand in harm's way, so I used a big burning piece of cardboard. You could blow the starch over a campfire or whatever, just be careful not to blow it toward anyone or anything that might catch fire.
3. Repeat as desired and then swish the water around in your mouth. Spit it out and repeat to clean your mouth. The big advantage of using corn starch over flour (which would also work) is that the corn starch rinses out pretty easily.

How It Works

A mass of corn starch will not easily burn (try it), but when you disperse the starch into a fine powder you can ignite it as a fuel. Starch, like sugar or flour, is a carbohydrate and can be burned. In fact, the dust burns instantly. If you've heard of a grain elevator explosion, this is the most common cause. A much smaller quantity of starch is used for this firebreathing trick.