Hobbies And Interests
Stalactites
Stalactites, which develop as water drips from the roof of a cave, should not be confused with stalagmites, which rise up from the cave floor. These formations can take many shapes; stalactites and stalagmites often join together to form columns. Other shapes look like straws or curtains. As the water drips from the top of the cave, calcium and other mineral deposits leave behind the shapes.
Materials
Before you can begin your experiment, you must gather your materials. To make your own stalactites with baking soda, you need yarn or string, scissors, hot water, paper clips, two glass jars and a saucer in addition to the baking soda. The yarn or string is for growing stalactites. Water with dissolved minerals held inside the glass jars act as the cave̵7;s roof, and the paper clips -- metal washers can also be used -- hold the string in place. Collect all the materials and place them on a table.
Procedure
Cut three pieces of yarn about 2 feet long and braid them together. Tie paper clips or washers to each end of the braided string. Boil water and fill each glass jar about two-thirds full of the hot water. Dissolve baking soda in the water until it will not dissolve anymore. Place the glass jars a few inches apart. Put each end of the string in each glass jar; each end should be at the bottom of the jars. The string should make a ̶0;U̶1; shape between the jars. Place a saucer in between the jars and underneath the string. Wait for a few days, and you will begin to see stalactites grow on the string.
Scientific Conclusions
Stalactites grow on your string because the water solution with the baking soda is transferred through the string. The water drips from the string onto the saucer, and the baking soda mineral is left behind on the string, forming the icicle-shaped stalactites. Stalagmites also grow as the water in the saucer evaporates, leaving behind the baking soda crystals. This experiment reproduces what actually happens in caves with rainwater and mineral deposits.