Making Your Own Bath Bombs

Bath bombs add a lot of fun to bath-time, and kids especially enjoy them. Most people make them in spheres, or half-spheres, but you can use candy and soap molds to make them in any shape you'd like. When you drop the bombs in water, they erupt into a cloud of tiny bubbles!
The ingredients that go into bath bombs give them effervescent properties, meaning that when the bombs are dropped into the bath water they react with it to release fizz. Bath bombs contain a bicarbonate (baking soda) and an organic acid (citric acid); the water suspends the two compounds and allows them to mix, and carbon dioxide gas is released as a result, which forms the bubbles. Bath bombs are always solid because if they were in a liquid form, there would be no way to prevent the bicarbonate and organic acid from reacting immediately. The fizz created by bath bombs won't sit on top of the water, like the foam created with bubble bath; instead it mixes with the water.
This recipe will make basic bath bombs, to which you can add colorants, dried herbs, essential oils and other additives.

1 part citric acid
2 parts baking soda
Witch hazel (in a spray bottle)
Dome-shaped mold, or other mold

Mix the citric acid and the baking soda together first. They must be blended completely, and you may want to consider using a mixer to ensure that they are, because if they aren't blended thoroughly enough, your bath bomb mixture will be grainy and the bombs won't be as fizzy. Add any colorants or other additives during this stage; make sure you don't add too much colorant, because even if the color of the mixture is light, the color will show up when the bombs get wet. Also, be sure to use powdered colorants, like mica, instead of liquid or gel colorants, as these types can cause the dry mixture to start its reaction.
Put the dry mixture in a large bowl, and as you stir it with one hand, spray it with the witch hazel using your other hand. Keep a close eye on the consistency of your mixture, and don't add too much witch hazel, which will make the mixture fizz, or too little, which will cause the bombs to be grainy and fall apart. If you take a bit of the mixture and pinch it between your fingers and it sticks together, it is ready to be put into the molds. Do this part of the process quickly, because waiting too long will allow the mixture to dry out, and adding more witch hazel to counteract this would ruin it.
Pack the mixture into the molds as tightly as possible, as this will minimize the chance they will fall apart, and create a better reaction when they are dropped into the tub. Wait a few minutes, then tap the bombs out onto a sheet of wax paper. Using the spray bottle, mist them once more with the witch hazel to create a hard outer shell which helps to keep them together. Leave the bombs out to air dry for three to four hours, and then package them in whatever way you see fit.
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