Q&A for How to Make Baking Soda Crystals

You can, but it probably will not cool as well; this will result in poor-quality or malformed crystals.

Some can, but it depends on the amount of water and the quality of the baking soda.

Baking soda crystals can keep growing for weeks.

Keep adding baking soda until the water no longer dissolves it.

No, you will not be able to make stalactites or stalagmites if you try growing them in a cup.

Cups are just an example. Any item can be used as long as it's small but has enough space for the baking soda crystals to grow. Consider using objects such as containers, jars, or glass bottles if you don't have or don't want to use cups.

Yes, you could. You may need to use more solution to get a sponge that is fully covered with crystals, because it has a larger surface area than string. Don't squeeze the sponge after you have grown the crystals, because they will fall off and break.

Calcium chloride and baking soda make a chemical reaction, not crystals. Just using baking soda works. If you want different crystals, try using sugar, salt, alum and Epsom salts.