What you need:
A cloth rag, two glasses, a plate, string, scissors, washing soda, hot water
What to do:
1. Fill the two glasses with hot water. Add about half a cup of washing soda into each glass. Keep the glasses on a table or on the floor.
2. Fold the rag diagonally and then roll it up tightly.
3. Cut three equal lengths of string. Tie the rolled-up rag at the centre and the sides using the string.
4. Trim off the extra length of the string.
5. Place either end of the rag into a glass. Lower the centre of the rag so that it dips downwards.
6. Place the plate underneath this dip and leave the set-up undisturbed for three to five days. Keep observing it.
What happens:
Gradually, a stalactite of washing soda is formed. It hangs from the dip in the rag and reaches the plate underneath!
Why?
First, washing soda is added to hot water which is more accepting than cold water so you can dissolve an excess of washing soda in the water while it’s hot
This washing soda solution travels up the cloth through a process called capillary action Capillary action is the movement of a liquid against gravity through narrow spaces This is the same principle that allows water to be absorbed by a tree’s roots and transported to its leaves
In this case, narrow spaces or capillanes are present in the cloth they absorb water and pull it upward
This happens until the cloth gets so full of the solution that it cannot hold any more. That’s when the extra washing soda starts dripping from the doth onto the plate As the water cools, it cannot keep the excess washing soda dissolved and deposits it on the rag or on the plate, giving you a soda pillar!
Picture Credit : Google
