I have a secret….you would never guess….but I’m a witch! Not an ordinary witch that throws eye of newt and bat wings in a boiling cauldron, but a witch of science. I can make a stream of water bend, without magic words, but with a negatively charged spoon.
How to create magic:
Rub a plastic spoon on your hair until the spoon acquires an electric charge (you can tell an electric charge is present when your hair is attracted to a spoon). Use a knife or other tool to create a tiny hole at the bottom of a plastic cup. Fill the cup up with water and then hold the spoon very close to the stream of water coming from the hole in the cup. The stream of water should be bent towards the spoon.
To understand what’s happening you need to learn about the electrical charges present on the water molecule. A water molecule is composed of one negative oxygen atom and two positive hydrogen atoms. These molecules are oriented in random directions, when you place the spoon near the stream of water molecules, the negative charge of the spoon attracts the slight positive charge of the hydrogen atoms. The water molecules are reoriented so that the hydrogen atoms are pointed towards the spoon. This reorientation of the water molecules cause the water to bend towards the spoon.
Try this activity with vegetable oil. Did the oil bend? No. This is because vegetable oil is composed of nonpolar molecules (unlike a water molecule which is polar). A polar molecule is a asymmetrical molecule that is composed of opposite charges. In the case of a water molecule it has a slight positive charge on one side of the molecule (the two hydrogens) and a slight negative charge on the other side of the molecule (the one oxygen).