In this FACTivity, you will grow your own speleothem. At the end of this FACTivity, you answer the following question: What does this activity tell us about the formation of speleothems?

Materials (for each student or group of students):

• Pictures of decorated cave passages
• Epsom salts, washing soda, or baking soda (Epsom salts and washing soda are more likely to form larger formations)
• Warm water
• 2 plastic cups of the same size (preferably clear or see-through)
• 1 piece of aluminum foil to make a tray or saucer
• 1 spoon
• 1 length of cotton string or yarn (30-50 cm in length)
• 2 paper clips
• Permanent markers